MASS TIMBER RESIDENTIAL BUILDINGS IN LONDON: A LOW CARBON ENVELOPE

UNIVERSITY OF WESTMINSTER COLLEGE OF DESIGN, CREATIVE AND DIGITAL INDUSTRIES

SCHOOL OF ARCHITECTURE AND CITIES

MSc ARCHITECTURE & ENVIRONMENTAL DESIGN 2018/19 Sem 2&3 Thesis Project Module

MASS TIMBER RESIDENTIAL BUILDINGS IN LONDON: A LOW CARBON ENVELOPE

JULIA PINHEIRO RIBEIRO SEPTEMBER 2019

ABSTRACT With the increase in urban population worldwide, the built floor area is also expected to grow at a fast speed. As construction and operation of buildings account for a significant percentage of the global carbon emissions, design and construction decisions should aim to reduce GHG emissions, stress and exhaustion of natural resources.

The building regulations in the UK specify targets for operational carbon emissions and building fabric performance, but not for embodied carbon. One of the leading countries to adopt cross-laminated timber, the UK has a milder and warmer climate than Canada, Scandinavian countries and Central Europe, where CLT has also been largely used.

This research investigates mass timber for multistorey residential buildings in London and its ability to deliver environmental comfort as well as a lowcarbon construction.

The analytic studies suggest that the lack of thermal mass in CLT buildings offers higher risk of overheating and reduced free running hours within comfort in summer, although solar gains and ventilation play a major role in providing thermal comfort throughout the year. Nonetheless, the annual

regulated loads are very similar in solid timber and concrete/masonry mechanically controlled buildings, resulting in similar operational carbon emissions. The embodied carbon in CLT buildings is markedly lower than in mineral constructions, even excluding wood carbon storage.

Although this research is based on a case study as a base case, the methodology seeks to expand the applicability of the findings, as the flats’ floor area and layout may be considered typical for multistorey residential buildings in London, and the analysis comprehends different solar exposures by considering four orientations. The methodology is replicable for other climates, provided that the construction scenarios are coherent to the local industry and practice, and the operational modes and adaptive comfort criteria are adequate to the environmental context.

TABLE OF CONTENTS 1.INTRODUCTION 1

1.1

The curent global contex

1

1.1.1

Urbanisation trend and housing shortage:

1

1.1.2

Climate crisis

1

1.1.3

Carbon emissions from buildings

1

1.2

Timber as a low embodied carbon material

2

1.3

Research questions and hypothesis

3

1.4

Methodology and research methods

3

1.4.1

Theoretical background

3

1.4.2

Context and precedents

3

1.4.3

Analytic studies

3

Outcomes and conclusion

5

1.4.4.

2.1 Carbon emissions and climate crisis

7

2. THEORETICAL BACKGROUND

7

9

2.2. Carbon emissions in buildings

2.2.1.

The contribution of the construction sector

2.2.2.

The UK building regulations and policies for carbon emissions

11

2.2.3.

Embodied and operational carbon

13

2.2.4.

Thermal comfort and annual loads

17

2.3.

An overview of timber constructions

9

21

2.3.1.1. Fire protection

23

2.3.1.2. Thermal properties

25

3.

CONTEXT AND PRECEDENTS

29

3.1.

London climate

29

3.2.

Built precedents

31

3.2.1.

Embodied carbon: CLT buildings in the UK

31

3.2.2.

Operational carbon:

the influence of the thermal mass and other design variables

37

3.2.3.

Thermal performance and annual loads in mid-rise CLT buildings in London

41

4.

ANALYTIC WORK

43

4.1.

Methodology

43

4.2.

The case study

45

4.4.

Construction scenarios

51

4.5.

Operation scenarios

54

4.5.1.

Free-running mode

54

4.5.2.

Mixed mode

55

4.5.3.

Mechanical mode

55

4.6.

Hypothesis for simulations

56

4.7.

Analysis overview: the influence of orientation

57

4.8.

Detailed analysis: the influence of construction in thermal comfort and annual loads

60

4.8.1. Base case / Scenario A: the existing building

60

4.8.2.

Scenario B

64

4.8.3.

Scenarios C and D – exposed thermal mass: ceiling

67

4.8.4

Scenario E - exposed thermal mass: ceiling and walls

68

4.9.

Embodied carbon

5.

RESEARCH OUTCOMES AND DESIGN APPLICABILITY

73 77

6. CONCLUSION

83

7. REFERENCES

87

8. APPENDIX

91

8.1.

Conditions for dynamic thermal simulations in EDSL TAS

91

8.2.

Construction scenarios

93

8.3.

Summer temperature profile - base case and scenario E

98

8.4.

Cold week temperature profile - base case / scenario A

102

8.5.

Cold week temperature profile - scenario B

106

8.6.

Cold week temperature profile - scenario C

111

8.7.

Cold week temperature profile - scenario D

116

8.8.

Cold week temperature profile - scenario E

121

8.9.

Warm week temperature profile - base case / scenario A

126

8.10.

Warm week temperature profile - scenario B

130

8.11.

Warm week temperature profile - scenario C

134

8.12.

Warm week temperature profile - scenario D

139

8.13.

Warm week temperature profile - scenario E

144

8.14.

Cold week temperature profile - OT - all scenarios

148

8.15.

Warm week temperature profile - OT - all scenarios

151

8.16.

Adaptive Overheating (CIBSE TM52)

154

8.17.

Domestic Overheating (CIBSE TM59)

157

8.18.

Frequency of overheating - comparison of all scenarios

160

LIST OF FIGURES Figure 2. “The existing built floor area is expected to nearly double by 2050 globally.” (GABC, 2017).

(softwood) and pores (hardwood). In red: spruce, a softwood.

In blue: ash, a hardwood (Arup, 2019).

Figure 2.1.1. Global warming potential (GWP) of greenhouse gases (GHG) (IPCC, 2007).

Figure 2.3.1.2.2. Temporary CLT structure in hardwood (tulipwood): MultiPly - London Design Festival, by Waugh Thistleton Architects (London, 2018). Available from: http:// waughthistleton.com/multiply/.

Figure 2.1.2. Observed global temperature change and modeled responses to stylised anthropogenic emission and forcing pathways - Global warming relative to 1850-1900 (oC) (IPCC, 2018)Figure 2.1.3. Breakdown of contributions to global net CO2 emissions in four illustrative model pathways (IPCC, 2018).

Figure 2.1.4. Electricity generation CO2 emission intensity (EEA, 2018).

Figure 2.2.1.1. Global share of buildings and construction final energy and emissions, 2017 (UNEP, 2018).

Figure 2.2.1.2. Global buildings sector energy use and intensity by end-use, 2000-17 (IEA, 2019).

Figure 2.2.1.3. Urban and rural world population projected to 2050 (UN, 2018).

Figure 2.2.1.4. Share of the population living in urban areas – 2018 and projected to 2050 (UN, 2018).

Figure 2.2.2.1. Hard-to-reduce sectors and the 2050 target (CCC, 2016).

Figure 2.2.2.2. Fuel factor for the Dwelling Emission Rate (DER) calculation required in the Building Regulations Part L1A (Ministry of Housing, Communities and Local Government, 2016).

Figure 2.2.2.3. Limiting fabric parameters: U-values to achieve the Target Emissions Rate (TER) and Target Fabric Energy Efficiency (TFEE) of the Building Regulations Part L1A (Ministry of Housing, Communities and Local Government, 2016).

Figure 2.2.3.1. Projected trend in life-cycle carbon in buildings in terms of scope and allocation (Zizzo et al., 2017).

Figure 2.2.3.2. End-of-life scenarios: landfill (LF), landfill with 50% of CLT panels sent for reuse (LF 50% reuse) and incineration (INC). Results are presented relative to the landfilling scenario (O'Connor et al., 2013).

Figure 2.2.3.5. Heat flow inwards through a real wall (continuous line), compared to a “zero-mass” wall of the same U-value (Szokolay, 2008).

Figure 2.3.1.1. Cross section of a solid timber beam that has been exposed to fire. The charred layer preserves the structural integrity of the centre of the timber cross section (Kaufmann et al., 2018).

Figure 2.3.1.2.1. Microscopic structure of wood: tracheids

Figure 2.3.1.2.3. Temporary CLT structure in hardwood (tulipwood): The smile - London Design Festival, by Alison Brooks (London, 2016). Available from: http://www. alisonbrooksarchitects.com/project/the-smile/.

Figure 2.3.1.2.4. Permanent CLT structure in hardwood (tupliwood): Maggie’s Oldham cancer centre, by dRMM (Oldham, UK, 2017). Available from: http://drmm.co.uk/ projects/view.php?p=maggies-oldham.

Figure 3.1.1. World map of Koppen-Geiger climate classification.

Available from: http://koeppen-geiger.vu-wien.ac.at/pics/20012025_A1FI.gif Figure 3.1.2. Monthly average climate data – projection to 2050 (medium-emissions scenario AB).

Figure 3.1.3. Monthly average global vertical radiation – projection to 2050 (medium-emissions scenario A1B).

Figure 3.2.1.1. Stadthaus, London. Construction details: lightweight cladding in wood pulp. (Waugh Thistleton Architects, 2009) Figure 3.2.1.2. Stadthaus, London. Photograph. (Waugh Thistleton Architects, 2009) Figure 3.2.1.3. Stadthaus, London. Plan and section: mass timber elements in yellow (Waugh Thistleton Architects, 2009) Figure 3.2.1.4. Bridport house, London. Plan: all walls and slabs are in CLT (Karakusevic Carson Architects, 2011).

Figure 3.2.1.5. Bridport house, London. Section: the external walls are brick-clad (Karakusevic Carson Architects, 2011).

Figure 3.2.1.6. Bridport house, London. The building’s southeast aspect is shaded with balconies (Karakusevic Carson Architects, 2011).

Figure 3.2.1.7. Whitmore Road (Waugh Thistleton Architects, 2012).

Figure 3.2.1.8. Trafalgar place (dRMM, 2015).

Figure 3.2.1.9. Cobalt Place (Allford Hall Monaghan Morris Architects, 2015).

Figure 3.2.1.10. Wenlock cross (Hawkins\Brown, 2015).

Figure 3.2.2.1. Heating demand for the whole house across different construction types (TRADA, 2015).

Figure 3.2.2.2. Percentage of occupied hours in a bedroom over a range of temperatures across different construction types (simulation projected to 2050 climate) (TRADA, 2015).

Figure 3.2.2.3. Percentage of occupied hours spent over certain temperatures across different construction types for the living room with 1990s weather (TRADA, 2015).

Figure 3.2.2.4. Temperature profile of a bedroom over a two-day period for various shading and ventilation strategies (TRADA, 2015).

Figure 3.2.2.5. Increased shading and ventilation: the response of light and heavyweight structures is similar (Ferk et al., 2016).

Figure 3.2.2.6. Reduced shading and ventilation: the amplitude of temperature swings is larger in lightweight structures (Ferk et al., 2016).

Figure 3.2.2.7. Exceedance hours above 27°C: the response of light and heavyweight structures is similar under increased ventilation and shading conditions (Ferk et al., 2016).

Figure 3.2.2.8. Number of nights above 25°C: the response of light and heavyweight structures is similar under increased ventilation and shading conditions (Ferk et al., 2016).

Figure 3.2.2.9. Energy requirement for cooling (kWh/m2): the response of light and heavyweight structures is similar under increased ventilation and shading conditions (Ferk et al., 2016).

Figure 3.2.2.10. Summer profile: the temperature swing amplitude in heavyweight structures is lower than in lightweight.

The temperatures in CLT construction may reach 1K above the concrete construction, even under increased ventilation and shading conditions (Ferk et al., 2016).

Figure 3.2.2.11. Space conditioning energy savings in a CLT twostorey single-family house in the US (Glass et al., 2013).

Figure 3.2.2.12. Space conditioning energy savings in a CLT fourstorey residential building in the US (Glass et al., 2013).

2014).

Figure 4.2.5. Flat in Dalston Works: the timber structure is concealed internal and externally (Waugh Thistleton Architects, 2014).

Figure 4.2.6. Dalston Works envelope: external materials palette (Waugh Thistleton Architects, 2014).

Figure 4.2.7. Dalston Works: site location and typical plan - 3rd floor (Waugh Thistleton Architects, 2014).

Figure 4.3.1. North flat floor plan (Waugh Thistleton Architects, 2014).

Figure 4.3.2. South flat floor plan (Waugh Thistleton Architects, 2014).

Figure 4.3.3. West flat floor plan (Waugh Thistleton Architects, 2014).

Figure 4.3.4. East flat floor plan (Waugh Thistleton Architects, 2014).

Figure 4.3.5. Dalston Works elevations (Waugh Thistleton Architects, 2014).

Figure 4.4.1. Base case (scenario A): cross-laminated timber constructions. Details developed according to Waugh Thistleton Architects’ drawings available from the Hackney Council Planning website.

Figure 4.4.2. Scenario B: reinforced concrete structure and masonry walls.

Figure 4.4.3. Scenario C: cross-laminated timber constructions; exposed CLT slab.

Figure 4.4.4. Scenario D: reinforced concrete structure and masonry walls; exposed concrete slab.

Figure 4.4.5. Scenario E: reinforced concrete structure and masonry walls; maximised exposed thermal mass.

Figure 4.7.1. Annual loads according to flat orientation.

Figure 4.2.1. Dalston Works, London. Designed in 2014 and completed in 2017 (Waugh Thistleton Architects, 2019)

Figure 4.7.2. Annual heating and cooling loads (mechanical mode) – North flat.

Figure 4.2.2. The building weight and foundations depth were limited by the Crossrail tunnel that crosses the plot underground (Waugh Thistleton Architects, 2014).

Figure 4.7.3. Annual heating and cooling loads (mechanical mode) – South flat.

Figure 4.2.3. The honeycomb structure in CLT comprises floor slabs, internal walls, stairs and external walls (Shearing, 2017).

Figure 4.2.4. Dalston Works section: the timber structure is concealed internal and externally (Waugh Thistleton Architects,

Figure 4.7.4. Annual heating and cooling loads (mechanical mode) –West flat.

Figure 4.7.5. Annual heating and cooling loads (mechanical mode) – East flat.

Figure 4.8.1.1. Frequency of operative temperature above

26oC during occupancy hours – free-running mode. Base case / Scenario A – North flat.

Figure 4.8.1.1. Cold week temperature profile – free-running mode. Base case / Scenario A – North flat - single bedroom.

Figure 4.8.1.2. Cold week temperature profile – free-running mode. Base case / Scenario A – South flat – Living room/kitchen.

Figure 4.8.1.3. Warm week temperature profile – free-running mode. Base case / Scenario A – North flat - single bedroom.

Figure 4.8.1.4. Warm week temperature profile – free-running mode. Base case / Scenario A – West flat – Single bedroom.

Figure 4.8.1.5. Warm week temperature profile – free-running mode. Base case / Scenario A – South flat – Living room/kitchen.

Figure 4.8.2.1. Cold week temperature profile – free-running mode. Scenario B – North flat - single bedroom.

Figure 4.8.2.2. Cold week temperature profile – free-running mode. Scenario B – South flat – Living room/kitchen.

Figure 4.8.2.3. Warm week temperature profile – free-running mode. Scenario B – North flat - single bedroom.

Figure 4.8.2.4. Warm week temperature profile – free-running mode. Scenario B – West flat – Single bedroom.

Figure 4.8.2.5. Warm week temperature profile – free-running mode. Scenario B – South flat – Living room/kitchen.

Figure 4.8.4.1. Cold week temperature profile – free-running mode. Base case and all hypothetical scenarios – North flat single bedroom.

Figure 4.8.4.2. Cold week temperature profile – free-running mode. Base case and all hypothetical scenarios – South flat – Living room/kitchen.

Figure 4.8.4.3. Warm week temperature profile – free-running mode. Base case and all hypothetical scenarios – North flat single bedroom.

Figure 4.8.4.4. Warm week temperature profile – free-running mode. Base case and all hypothetical scenarios – West flat – Single bedroom.

Figure 4.8.4.5. Warm week temperature profile – free-running mode. Base case and all hypothetical scenarios – South flat – Living room/kitchen.

Figure 4.8.4.6. Frequency of operative temperature above 26oC during occupancy hours – free-running mode. Base case and all hypothetical scenarios – North flat.

Figure 4.8.4.7. Frequency of operative temperature above 26oC during occupancy hours – free-running mode. Base case and all

hypothetical scenarios – South flat.

Figure 4.8.4.8. Frequency of operative temperature above 26oC during occupancy hours – free-running mode. Base case and all hypothetical scenarios – West flat.

Figure 4.8.4.9. Frequency of operative temperature above 26oC during occupancy hours – free-running mode. Base case and all hypothetical scenarios – East flat.

Figure 4.8.4.10. Annual heating and cooling loads + frequency of operative temperature above 26oC during occupancy hours – mixed mode. Base case and all hypothetical scenarios – North flat.

Figure 4.8.4.11. Annual heating and cooling loads + frequency of operative temperature above 26oC during occupancy hours – mixed mode. Base case and all hypothetical scenarios – South flat.

Figure 4.8.4.12. Annual heating and cooling loads + frequency of operative temperature above 26oC during occupancy hours – mixed mode. Base case and all hypothetical scenarios – West flat.

Figure 4.8.4.13. Annual heating and cooling loads + frequency of operative temperature above 26oC during occupancy hours – mixed mode. Base case and all hypothetical scenarios – East flat.

Figure 4.8.4.14. Annual heating and cooling loads + frequency of operative temperature above 26oC during occupancy hours – mechanical mode. Base case and all hypothetical scenarios – North flat.

Figure 4.8.4.15. Annual heating and cooling loads + frequency of operative temperature above 26oC during occupancy hours – mechanical mode. Base case and all hypothetical scenarios – South flat.

Figure 4.8.4.16. Annual heating and cooling loads + frequency of operative temperature above 26oC during occupancy hours – mechanical mode. Base case and all hypothetical scenarios – West flat.

Figure 4.8.4.17. Annual heating and cooling loads + frequency of operative temperature above 26oC during occupancy hours – mechanical mode. Base case and all hypothetical scenarios – East flat.

Figure 4.9.1. Contribution of building elements to embodied carbon (excluding carbon storage).

Figure 4.9.2. Contribution of building elements to embodied carbon (including carbon storage).

Figure 4.9.3. Embodied carbon per m2 – envelope.

Figure 4.9.4. Embodied carbon per m2 – floor/ceiling.

Figure 4.9.5. Embodied carbon per m2 – internal wall.

Figure 4.9.6. Embodied carbon per m2 – internal party wall.

Figure 4.9.7. Embodied carbon per m2 – North flat.

Figure 4.9.8. Embodied carbon per m2 – South flat.

Figure 4.9.9. Embodied carbon per m2 – West flat.

Figure 4.9.10. Embodied carbon per m2 – East flat.

Figure 5.1. Embodied carbon per m2 of building element.

Figure 5.2. Weighted average of embodied carbon in the typical floor of the case study building, considering the base case and four hypothetical scenarios.

Figure 5.3. Embodied and operational carbon – 30-year lifespan (no carbon storage).

Figure 5.4. Embodied and operational carbon – 30-year lifespan (with carbon storage).

Figure 5.5. Embodied and operational carbon – 60-year lifespan (no carbon storage).

Figure 5.6. Embodied and operational carbon – 60-year lifespan (with carbon storage).

Figure 5.7. Embodied and operational carbon – 100-year lifespan (no carbon storage).

Figure 5.8. Embodied and operational carbon – 100-year lifespan (with carbon storage).

Figure 5.9. Warm season temperature profile of the free-running mode. The lowest and highest thermal mass constructions are depicted (base case and scenario E) - East flat single bedroom (west facing room).

ACKNOWLEDGEMENTS I would like to thank my colleagues, the teaching staff, the librarians and the university academic support in this challenging year.

I am especially grateful to professor Dr. Rosa Schiano-Phan, who has shared her wide knowledge and given essential and restless guidance and assistance to all students.

I am also very pleased to have been granted an International Part Fee scholarship from the University of Westminster, which contributed to make it possible to do these postgraduate studies.

My highest gratitude to my husband, parents and siblings for their immensurable support.

“CO2 emissions resulting from material use in buildings account for 28% of the annual buildings� related CO2 emissions. Most of these emissions are a result of cement and steel manufacturing, which have high process emissions and are used in large quantities.� (IEA, 2018)

1.

INTRODUCTION

This research investigates timber structure buildings as part of the construction sector response to the

1.1

climate crisis. This section provides an overview on the study content.

The curent global contex

1.1.1 Urbanisation trend and housing shortage: The rapid and intense process of urbanisation puts the existing cities under pressure. By 2050 more than 68% of the world’s population will be living in cities. This means approximately 3.5 billion more people living in urban areas within 30 years (United Nations, Department of Economic and Social Affairs, Population Division, 2018).

Although the housing crisis in big cities is also strongly related to speculation and financialisation of properties, the shortfall of affordable dwellings is a major global urban issue.

According to the UN-habitat (2018), almost 900 million people live in overcrowded informal settlements. Big cities in Latin America, Asia and Africa are markedly affected, but urban areas of developed regions are not immune to urban disparities among the living conditions of their citizens.

1.1.2 Climate crisis The latest special report issued by IPCC (2018) brings the potential impacts and risks of the global temperature increase by 1.5°C since the pre-industrial age, which is likely to happen in 2030 if global emissions keep the current trends.

Anthropogenic action has been mostly responsible for this rapid warming, due to continuous, increasing and cumulative effect of greenhouse gas emissions.

Construction, both offsite and on-site, accounts for a significant percentage of global carbon emissions.

According to the International Energy Agency prediction (2019), the existing built floor area is

“expected to nearly double by 2050 globally”. The same report also foresees an increase by 35% in the demand for cement (and thus also sand) and steel in this period, considering them the most preferred building systems.

1.1.3 Carbon emissions from buildings Buildings operation is a major contributor of global energy demand and related CO2 emissions. In 2017, 39% of global CO2 emissions where related to buildings construction and operation (IEA and UN: 2018). Although residential buildings require less energy and emit less carbon than industrial buildings operation, dwellings represent 80% of the total floor area built in the world. Considering the increase in housing demand related to urbanisation trends, any better practice implemented for low emissions and energy consumption in residential buildings may have a huge impact on the overall emissions scenario.

Design play a significant role in determining the energy required to maintain comfortable conditions in cold and warm climates and seasons: urban context, massing, internal layout, building structure and envelope construction. According to the IEA report Perspectives for the Clean Energy Transition (2019), “delaying building envelope measures by ten years would increase expenditures by USD 2,500 billion to 2050, which is more than 2.5 times operational expenditures for heating and cooling in 2017”.

Buildings energy demand comprises operational and embodied energy. Since the UK regulations are leading to low operational energy and carbon buildings, the embodied energy is the next challenge to tackle in construction (Soulti, E., Moncaster, A., 2014).

1

1.2

Timber as a low embodied carbon material

The extraction of primary resources and manufacture of building materials is the most carbon intensive stage of buildings’ lifecycle, responding for 50% of the embodied carbon (Soulti, E., Moncaster, A., 2014). Therefore, there is an opportunity for reduction in carbon emission by improving manufacturing processes and preferably selecting less intensive energy and carbon materials.

Lightweight constructions such as timber and steel structures and lightweight partitions result in reduced concrete foundations. Since mineral materials (cement, gravel, sand) are the most carbon intensive, the use of timber is not only beneficial for the carbon storage within it, but also for the reduction in concrete demand for the foundation.

Carbon sequestration causes a positive impact to the embodied carbon calculation in timber until the end of its life, when it may be disposed in a landfill or incinerated. The emitted gases may be directly converted into energy or stored as BECCS (CCC, 2018). Nonetheless, there is controversy about whether biomass carbon storage in timber and BECCS being effectively carbon negative.

Construction disposal is an issue that concerns all building materials, though. Reusing and recycling may also involve processes that require different amounts of energy. At the end of the lifecycle, disposal of materials causes environmental impacts that should be carefully considered. In landfills, mineral and metal-based building elements do not release gases but represent a poor and potentially harmful land use. If carbon sequestration is not considered in wood EC calculations due to the end of its life, an assessment of the impact of other materials’ final stage of life must be considered to keep consistency of methodology.

Waste in construction sites also represents a significant amount of EE in the UK, mostly because

2

of overordering of on-site building systems. Offsite manufacturing produces significant less waste (Soulti, E., Moncaster, A., 2014).

The advantages of using timber structures are related to the environmental aspects described above, but also to the structural properties and dynamics of construction. Some reasons why the industry is increasingly adopting timber building systems and trying to make it feasible in high rise constructions are outlined below.

Wood is a natural carbon sink, renewable and reusable. It does not emit toxic gases to the built environment neither during construction nor during its lifetime. As it is lightweight, it requires shallow foundations, an advantage for locations with underground urban infrastructure or any limitation in building underground. It alternatively allows to build higher with a same depth/heavy foundation meant for a concrete structure.

Timber structure relies upon offsite prefabrication an on-site assembly, so the construction stage of structure is much shorter for timber than for cast-inplace concrete, requiring less workers on-site, more precision and less waste. Prefabricated systems also allow optimized transport of building material, meaning less impact on the site neighbourhood and less pollution by trucks. The fact that it is a dry and quick assembly construction makes it viable to build in any weather condition through the entire year.

Depending on the building system, timber may provide a very good insulation and air tightness.

There is extensive research proving that timber is less carbon intensive than other materials (CCC, 2018). However, keeping operational energy of timber buildings low may require construction elements that may make EC levels not lower than in mostly used building systems.

1.3

Research questions and hypothesis

The objective of this research is to discuss if mass timber multi-storey residential buildings in London are effectively low in carbon, compared to a typical concrete and masonry construction.

and internal constructions combine low and intensive-carbon materials. Moreover, other design variables may significantly influence the building performance.

The hypothesis is that buildings in CLT structure may be lower in carbon, even if the envelope

1.4

Methodology and research methods

1.4.1 Theoretical background

1.4.3 Analytic studies

The research is based on a literature review linking the built environment, carbon emissions and climate crisis. The potential of architectural design to tackle energy demand at different building life stages is discussed, including key concepts involved in passive thermal comfort, embodied and operational carbon, and design variables that influence the building response to the climate.

OBJECTIVE

1.4.2 Context and precedents This section summarizes findings from the academia and industry on the thermal performance and energy efficiency of CLT residential buildings.

It presents a panorama of existing residential buildings in CLT in the UK. The criteria for this review comprehend an overview of the climate and urban context, building typology, envelope construction and embodied carbon.

The second part presents theoretical studies comparing timber lightweight buildings and typical masonry heavyweight constructions.

The final part of this review brings detailed research published on this topic is focused on a comparison between the CLT building in the UK, Stadthaus (Waugh Thistleton Architects, 2009) and Bridport house (Karakusevic Carson Architects, 2011), both in Hackney, London.

The objective of the analytic work is to understand to what extent does CLT contribute to low carbon buildings. It aims to explore how low in embodied and operational carbon is a CLT building comparing to the typical construction, for the same architectural design.

The study is focused on assessing the embodied carbon of the building envelope only, which usually accounts for the largest embodied carbon of a building, after the structure and foundations. (RICS, 2012). These two major contributors were excluded from the calculations because the comparison between quantities of material in different structural systems requires structural calculations, which lies outside this research scope. The building envelope is the component that mediates the interaction between indoor and outdoor environment, so it is the most relevant construction that influences the annual regulated loads and, therefore, the operational carbon.

THE CASE-STUDY The research was based on computational simulation analysis of a residential building in London, considering the climate data for the medium carbon emissions scenario predicted for

3

2050. The thermal performance and annual loads were assessed against CIBSE criteria for overheating and adaptive thermal comfort, and the building regulations’ target for the fabric energy efficiency.

A recently built mid-rise residential building in CLT was chosen for the base case analysis: Dalston Lane (Waugh Thistleton Architects, 2017), in the London Borough of Hackney. It is a milestone for the CLT industry as it is the world’s largest pure CLT-structure building, reaching up to 10-storey.

Mass timber is used for the external, party and core walls, floors and stairs. However, there is no exposed timber neither external nor internally. The facades are brick-clad, and the interior walls are encapsulated in plasterboard for fire safety and finishing.

METHODOLOGY OF ANALYSIS The analytical studies consisted in a sequence of computational dynamic thermal simulations using TAS Engineering EDSL to obtain the annual heating and cooling loads, the operational energy (OE).

The embodied carbon (EC) of each scenario was calculated according to a recognized cradle-togate database reviewed from literature (Jones, C., Hammond, G., 2019).

The simulations were carried out for flats facing four building aspects – north, south, east and west - enabling the study to explore the effect of different conditions for solar radiation. The purpose of covering representative building orientations is to expand the applicability of the findings. The thermal analysis is focused on the rooms that are occupied for longer periods: living room/kitchens (the combined space) and bedrooms.

The outputs from the simulations in TAS used to assess the operational energy are the annual heating and cooling loads, frequency of adaptive thermal comfort and potential overheating within the assessed residential units. The cold and warm seasons were analysed by a week temperature

4

profile in January and July.

The energy demand for lighting and appliances will not be considered in the OE calculations. This research will briefly assess the daylight availability within the selected units, but further reduction in energy demand for artificial lighting is not part of the study scope. Despite the increasing number of domestic electric appliances, the plug loads are a topic for an expanded research field that includes but is not restricted to behaviour, social development trends, technology development and affordability.

The energy and carbon involved in the building’s end of life is not included in the comparison.

Exploring this life stage would require an analysis of the current and projected technologies for recycling and disposing of the studied envelope materials, which would expand the research beyond the technical field of this study.

The objective of the analysis is to compare the EC and OE of different options of constructions for the same architectural design, rather than focusing on the post-occupancy evaluation of the existing building. Since the study is based on hypothetical construction scenarios, fieldwork is not a priority to achieve the research goal. Limitations in time and access to occupied residential units and time constraints also contributed to frame the research scope.

The first step of analysis is the calculation of embodied carbon within the building envelope and the simulation of annual operational energy demand of an existing mid-rise residential building in London, considering the existing building in CLT as a base case scenario. Another four scenarios were simulated, considering mass timber and concretebased constructions, as well as encapsulated and exposed thermal mass.

Although the computational analysis will not expand to this step, the benefits of manipulating other design variables.

1.4.4. Outcomes and conclusion The final results combine the operational carbon emissions from regulated loads in mechanical mode and the embodied carbon. The building lifespan influences the ratio between embodied and operational emissions, but either options result in timber as a lower in carbon. The presence of thermal mass in the construction provides improvements in thermal comfort during the warm season, but the control of solar gains and heat dissipation is way more relevant to maximise the free running mode and reduce operational carbon emissions.

5

OVERVIEW OVERVIEW GLOBAL CONTEXT GLOBAL CONTEXT URBANISATION URBANISATION TREND TREND HOUSING CRISIS HOUSING CRISIS

“THE EXISTING BUILT FLOOR AREA IS FLOOR EXPECTED TOISNEARLY DOUBLE BY 2050 GLOBALLY” “THE EXISTING BUILT AREA EXPECTED TO NEARLY DOUBLE BY 2050 GLOBALL (IEA, 2019) (IEA, 2019)

1X JAPAN FLOOR 1XAREA JAPAN FLOOR AREA EVERY SINGLE YEAR EVERY SINGLE YEAR Source: GABC, 2017 Source: GABC, (GABC, 2017) 2017

1X PARIS FLOOR1X AREA PARIS FLOOR AREA EVERY SINGLE WEEK EVERY SINGLE WEEK Source study-t Source: GABC, 2017 Source: GABC, 2017

“The existing built floor area is expected to double by 2050 globally” (IEA, 2018) 6

MASS

2. THEORETICAL BACKGROUND

2.1 Carbon emissions and climate crisis “Carbon emissions” refers to fuel and processrelated greenhouse gases (GHG) emissions.

High concentrations of them in the atmosphere interfere in the global heat exchanges, causing the greenhouse effect, and consequently the global warming and climate change. The GWP (global warming potential) of different gases is expressed as CO2 equivalent (CO2e) for a given time horizon (usually 100 years), so that their harmful effect is normalized and comparable (Figure 2.1.1).

The concentration of CO2 in the atmosphere was 407.4ppm in 2018, increasing by 0.6% compared to 2017 and far above the pre-industrial levels (180 – 280ppm). According to the latest IPCC Climate change and land report (2019), the 1.5oC

limit (Figure 2.1.2) defined in the Conference of Paris is only feasible with carbon sequestration and by cutting GHG emissions from change in land - such as deforestation, livestock and agricultural practices – and fossil fuel burning to provide energy for all sectors of the global economy (Figure 2.1.3).

Tackling the energy demand and shifting to low carbon energy generation is urgent and possible.

The European Environment Agency has published the CO2 intensity of electricity generation in the European Union since 1990 and there is a reduction trend. However, there is a huge disparity between countries. France and Sweden lead the low carbon generation, more than five-fold lower than the most carbon intensive energy generator, Bulgaria (Figure 2.1.4).

Figure 2.1.1. Global warming potential (GWP) of greenhouse gases (GHG) (IPCC, 2007).

Figure 2.1.2. Observed global temperature change and modeled responses to stylised anthropogenic emission and forcing pathways - Global warming relative to 1850-1900 (oC) (IPCC, 2007).

7

Characteristics of four illustrative model pathways Different mitigation strategies can achieve the net emissions reductions that would be required to follow a pathway that limits global warming to 1.5°C with no or limited overshoot. All pathways use Carbon Dioxide Removal (CDR), but the amount varies across pathways, as do the relative contributions of Bioenergy with Carbon Capture and Storage (BECCS) and removals in the Agriculture, Forestry and Other Land Use (AFOLU) sector. This has implications for emissions and several other pathway characteristics.

Breakdown of contributions to global net CO2 emissions in four illustrative model pathways Fossil fuel and industry

AFOLU

Billion tonnes CO₂ per year (GtCO2/yr) 40

BECCS

Billion tonnes CO₂ per year (GtCO2/yr) 40

P1

Billion tonnes CO₂ per year (GtCO2/yr) 40

P2

Billion tonnes CO₂ per year (GtCO2/yr) 40

P3

20

20

20

20

0

0

0

0

-20

-20 2020

2060

2100

2060

2100

P4

-20

-20 2020

2020

2060

2020

2100

2060

2100

P3: new energy generation technologies but small

P1: low energy with downsized A scenario in which social, demand scenario, P2: A scenario with a a broad focus on P3: A middle-of-the-road scenario in P4: A resource- and energy-intensive businessenergy and technological innovations sustainability including energy which societalin asdemand. well as technological scenario in which economic growth and reductions system. result in lower energy demand up to intensity, human development, follows historical globalization lead to widespread high economic growth and globalization based P2: sustainable but energy intensive scenario, with P4:development 2050 while living standards rise, economic convergence and patterns. Emissions reductions are adoption of greenhouse-gas-intensive onmainly resource, andthe energy-intensive especiallyinternational in the global South.cooperation A international cooperation, as well as achievedGHG by changing way in lifestyles, lifestyles including high demand for downsized energy system enables shifts towards sustainable and healthy which energy and products are transportation fuels and livestock rapid decarbonization of energy supply. consumption patterns, low-carbon produced, and to a lesser degree by products. Emissions reductions are Figure of contributions to global net CO emissions in four illustrativemainly model pathways.

Afforestation is the 2.1.3. only CDR Breakdown option technology innovation, and reductions in demand. achieved through technological 2 considered; neither fossil fuels with CCS Forestry well-managed land systems withUse; BECCS: Bioenergy with Carbon Capture means, making strong use of CDR AFOLU: Agriculture, and Other Land and Storage nor BECCS are used. limited societal acceptability for BECCS. through the deployment of BECCS. P1:

(IPCC, 2018).

Interquartile range

Global indicators

P1

Pathway classification

No or limited overshoot

No or limited overshoot

No or limited overshoot

-58

-47

-41

4

(-58,-40)

-93

-95

-91

-97

(-107,-94)

-50

-49

-35

-2

(-51,-39)

-82

-89

-78

-80

(-93,-81)

-15

-5

17

39

(-12,7)

-32

2

21

44

(-11,22)

60

58

48

25

(47,65)

77

81

63

70

(69,86)

-78

-61

-75

-59

(-78, -59)

in 2050 (% rel to 2010)

-97

-77

-73

-97

(-95, -74)

from oil in 2030 (% rel to 2010)

-37

-13

-3

86

(-34,3)

in 2050 (% rel to 2010)

-87

-50

-81

-32

(-78,-31)

from gas in 2030 (% rel to 2010)

-25

-20

33

37

(-26,21)

in 2050 (% rel to 2010)

-74

-53

21

-48

(-56,6)

59

83

98

106

(44,102)

150

98

501

468

(91,190)

-11

0

36

-1

(29,80)

-16

49

121

418

(123,261)

430

470

315

110

(245,436)

833

1327

878

1137

(576,1299)

0

348

687

1218

(550,1017)

0

151

414

1191

(364,662)

0.2

0.9

2.8

7.2

(1.5,3.2)

1

14

(-30,-11)

CO2 emission change in 2030 (% rel to 2010) in 2050 (% rel to 2010) Kyoto-GHG emissions* in 2030 (% rel to 2010) in 2050 (% rel to 2010) Final energy demand** in 2030 (% rel to 2010) in 2050 (% rel to 2010) Renewable share in electricity in 2030 (%) in 2050 (%) Primary energy from coal in 2030 (% rel to 2010)

gCO2/kWh

M

Summary for Policymakers

from nuclear in 2030 (% rel to 2010) in 2050 (% rel to 2010) from biomass in 2030 (% rel to 2010) in 2050 (% rel to 2010) from non-biomass renewables in 2030 (% rel to 2010) in 2050 (% rel to 2010) Cumulative CCS until 2100 (GtCO2) of which BECCS (GtCO2) Land area of bioenergy crops in 2050 (million km2)

Agricultural CH4 emissions in 2030 (% rel to 2010)generation Figure 2.1.4.

Electricity in 2050 (% rel to 2010) Agricultural N2O emissions in 2030 (% rel to 2010) in 2050 8 (% rel to 2010)

P2

P3

-48 (EEA, 2018).

-24 emission intensity CO 2

P4 Higher overshoot

No or limited overshoot

-33

-69

-23

2

(-47,-24)

5

-26

15

3

(-21,3)

6

-26

0

39

(-26,1)

NOTE: Indicators have been selected to show global trends identified by the Chapter 2 assessment.

National and sectoral characteristics can differ substantially from the global trends shown above.

* Kyoto-gas emissions are based on IPCC Second Assessment Report GWP-100 ** Changes in energy demand are associated with improvements in energy efficiency and behaviour change

2.2. Carbon emissions in buildings 2.2.1. The contribution of the construction sector Global energy-related carbon emissions have risen since 2017, after a short period of stable levels.

In 2018 there was an increase of 1.7%, reaching the mark of 33.1 GtCO2 (gigatons of CO2). The buildings sector responds for almost a third of it – or 3,000 Mtoe (million tonnes of equivalent oil) (Figure 2.2.1.1), and the major contributions to the increase in electricity demand are the cooling and heating needs (Figure 2.2.1.2), exacerbated by the extreme weather conditions that have happened more frequently every year. If energyrelated embodied carbon is considered, buildings and construction respond for roughly 40% of the global the CO2 emissions, or more than 11 GtCO2 (IEA, 2019).

According to the UN (2018), the world’s urban population has recently surpassed the rural agglomerations, and the projection for 2050 is that 68% of people will be living in cities (Figure 2.2.1.3).

In the same period, the built floor area is expected to double globally. These intertwined global trends are markedly more intense in developing countries, most of them in hot climate zones, where the global warming accentuates the cooling needs and peak

loads (Figures 2.2.1.4). In many of those countries, building regulations are incipient or completely absent, which often leads to poor thermal response and energy performance in buildings (UNEP, 2018).

Moreover, the rise in peak loads causes instability in the power system and raise the demand for additional capacity in energy generation, another driver to scale greenhouse gas emissions up.

The increase in global built floor area and energy demand has not been followed by significant reductions in the average carbon intensity of energy sources. If the peak values predicted to 2020 are registered before it, the transition to lower energy demand and carbon emissions will need to be even more abrupt to keep the rise in global temperature within 1.5oC by 2050. Despite any endeavours by the buildings and construction sector, the achievements will not be enough if decarbonisation in the power generation remains limited as it currently is. In the IPCC Faster Transition Scenario, CO2 emissions should drop by 3.6% yearly for the next 30 years, reaching 10 GtCO2 per year in 2050.

If the current emissions rate is not reduced, a mark of 36 GtCO2 will be registered instead, and it is very unlikely that the global mean surface temperature will be limited to 1.5oC above pre-industrial levels (IPCC, 2018).

Figure 2.2.1.1. Global share of buildings and construction final energy and emissions, 2017 (UNEP, 2018).

9

Figure 2.2.1.2. Global buildings sector energy use and intensity by end-use, 2000-17 (IEA, 2019).

Urban

6 4

1800

1500

2

2000 2050 Rural

billion

8

Figure 2.2.1.3. Urban and rural world population projected to 2050 (UN, 2018).

Figure 2.2.2.1. Hard-to-reduce sectors and the 2050 target (CCC, 2016).

10

The International Energy Agency (2019) estimates that the energy use in buildings should be drastically reduced by 30% in the Faster Transition Scenario.

Delaying actions by 10 years will cost 2 GtCO2 emissions and 3,500 Mtoe additional energy use, whereas improvements in the buildings’ envelope have a direct impact on the energy demand for space thermal comfort and may save 500 Mtoe per year from 2020 to 2050.

of natural resources is not necessarily carbonintensive, it may be predatory in other aspects. The thorough analysis of the environmental impact of buildings and construction is known as life cycle assessment, LCA, a methodology that expands beyond greenhouse gas emissions and is not limited to design and build stages. Quantifying the equivalent carbon emissions of a building during its life-time is part of it.

The Faster Transition Scenario projected to 2050 (UN, 2018) considers that improvements in the building fabrics have the potential to reduce energy demand for space heating and cooling by 40%.

Architectural design choices can contribute to lower it further, by controlling thermal losses, heat gains and heat flow.

2.2.2. The UK building regulations and policies for carbon emissions

In the current building stock in cold and mixed climate regions, a “typical performance building” consumes 120-200 kWh/m2 and a “poor performance building” uses approximately 200300 kWh/m2 for space heating (IEA, 2019). The target for new constructions should be around 1530 kWh/m2.

Besides the energy and emissions from operation, the contribution of material, processes and transport involved in construction is not negligible: in 2017 it represented more than 10% of the global emissions, with steel and cement contributing to more than half of this number (UN, 2018).

Aluminium, glass and insulation materials are the second major contributors.

The residential buildings subsector accounts for 80% of the global built floor area, 70% of the buildings’ energy consumption and 60% of the buildingsrelated carbon emissions. However, roughly a third of the residential energy is generated from biomass, that is considered carbon neutral despite being strongly connected to deforestation, land erosion and air pollution. Although the exploitation

2018

In the UK, building-related carbon emissions rose by 3% in 2018, although the residential subsector recorded a drop of 2% (CCC, 2019). In 2016, the Committee on Climate Change published a report on the UK heat policy where it analyses the potential for reduction in emissions to meet the UK Government’s target for 2050, which is 80% of the emissions in 1990. Some sectors are considered “hard-to-reduce”, whereas some others, like buildings, will need to target zero emissions (Figure 2.2.2.1).

The Government’s carbon reduction strategy sets the maximum CO2 emissions from regulated loads (kgCO2(eq)/m2/year), which must be achieved regardless of the space conditioning system and fuel types used. The non-profit organisation Zero Carbon Hub (2011) recommended a national minimum standard for a “Carbon compliance”, based on the building regulations available at that time. The recommended level for on-site low/zero carbon heat and power in low rise apartment blocks is 14 kg CO2e/m2/year. The fabric energy efficiency for the same building typology is 39kWh/m2/year (Zero Carbon Hub. 2016).

The Building Regulations Part L1A (2010) – Conservation of fuel and power for new dwellings, revised in 2016, sets performance requirements for

2050

Figure 2.2.1.4. Share of the population living in urban areas – 2018 and projected to 2050 (UN, 2018).

11

Figure 2.2.2.2. Fuel factor for the Dwelling Emission Rate (DER) calculation required in the Building Regulations Part L1A (Ministry of Housing, Communities and Local Government, 2016).

Figure 2.2.2.3. Limiting fabric parameters: U-values to achieve the Target Emissions Rate (TER) and Target Fabric Energy Efficiency (TFEE) of the Building Regulations Part L1A (Ministry of Housing, Communities and Local Government, 2016).

12

residential buildings. The document sets targets for the Dwelling CO2 Emission Rate (DER, in kgCO2/ m2 per year) and Dwelling Fabric Energy Efficiency (DFEE, in kWh/m2 per year). The calculations include the energy loads from the space conditioning and hot water, pumps and fans, and internal lighting.

A factor is applied to the calculation depending on the carbon-intensity of the fuel used to power those systems (Figure 2.2.2.2).

The compliance with the Building Regulations Part L is verified through the SAP 2012 version 9.93 (Standard Assessment Procedure, 2017), demonstrating that the new building meets the limiting system efficiency and fabric parameters (Figure 2.2.2.3), reasonable fabric air tightness, maximum acceptable solar gains in summer, and heat losses and gains from circulation pipes. The specification of construction types must include not only the U-values, but also the thermal mass parameter (250kJ/m2.K).

The Mayor has set an ambition for London to be a zero-carbon city by 2050 and, for that, buildings should be designed to keep their CO2e emissions below the targets defined by the Building regulations Part L (Mayor of London, 2018). If the development fails to achieve net zero carbon, it must contribute to the local planning authority carbon offset fund at the current reference price of ÂŁ60 per tCO2 over the assumed lifetime of 30 years. This value is under constant review to meet the Spatial Development Strategy for the Greater London. According to the Circular Ecology (Jones, C., Hammond, G.,2019), the embodied carbon involved in the construction of each m2 Gross Internal Area (GIA) in the UK is roughly 0.5 to 1.0 tCO2.

2.2.3. Embodied and operational carbon Carbon emissions happen at all stages of a building existence. The Embodied carbon working group of the Royal Institute of Chartered Surveyors (2019) divides buildings lifetime in the following stages: product, construction process, use, and end of life.

Embodied carbon is the CO2 equivalent greenhouse gases emissions resultant from all activities involved in the creation and dismantling or demolition of a building. It may either include the whole life cycle of a material or only parts of it, such as extraction of natural resources, manufacturing, use and re-use or disposal. There is a specific terminology for each of those different approaches: - Cradle-to-gate: it is limited to the product stage, and involves extracting, refining, transporting, and processing it to a finish product.

- Cradle-to-site: besides the product stage, it additionally includes transporting the product to the construction site.

- Cradle-to-end of construction: comprehends all processes from extraction to the final works, when the building is ready to be used.

- Cradle-to-grave: the demolition and disposal of materials are included in the assessment.

- Cradle-to-cradle: from the extraction of natural resources to the end of the building lifecycle, including the demolition or disassemble, reuse, recycle and disposal.

Embodied carbon calculations involve the knowledge of industrial and commercial processes

13

Figure 2.2.3.1. Projected trend in life-cycle carbon in buildings in terms of scope and allocation (Zizzo et al., 2017).

14

behind all phases of production, construction and disposal or recycling. The Inventory of Carbon and Energy (ICE) created a UK-based database of cradleto-gate embodied carbon. It considers a broad range of GHG and is measured in kgCO2e per kg of material.

materials to replace carbon-intensive ones.

Sathre and O’Connor’s (2010) analysis of GHG displacement factors of wood product substitution shows that every ton of dry wood used avoids, roughly, 3.9 tCO2e that would be emitted by using typical carbon intensive materials.

According to the ICE (2019), the embodied carbon accounts for 20-50% of the whole-life carbon in new buildings in the UK. As the sector adapts to increasingly tight regulations on thermal performance and energy efficiency aiming to zerocarbon, the hotspot for reductions will be embodied carbon (Figure 2.2.3.1).

The embodied carbon is usually calculated to define mitigating strategies and assess carbon emission savings against the equivalent operational carbon calculated for the building. It should be used to inform design decisions at early design stages, when there is still a certain flexibility to improve the building mass and choose the most appropriated construction systems.

There is a number of variables that apply specifically to timber: the ability of sequestering carbon, the sustainability of wood sources, the variable moisture content, the variety of wood species and density. This complexity shall be considered while calculating the embodied carbon in timber constructions. The carbon content in spruce CLT is 215.12kg/m³, which corresponds to a GWP (global warming potential) of -632 kgCO₂e (Kaufmann et al., 2018). The ICE database divides the timber section into “excluding” and “including carbon storage”.

The reason behind it is the carbon release at its end of life, although ICE is a cradle-to-gate database.

Wood end of life scenarios result in very different emissions (Figure 2.2.3.2). Landfilling it produces a slower GHG emission than incinerating, but the methane released is more harmful than CO2. If wood is used as biomass, it may be considered a net-zero carbon emission energy source, or at least replace the use of fossil fuel (O’Connor et al., 2013).

Despite the controversy about the effectiveness of timber as a carbon sink, there is a consensus about the benefits of using low embodied carbon

Strategies to achieve low embodied carbon should focus first on the most carbon-intensive building elements: the substructure and superstructure.

The specification of materials has a clear impact on it, and the building system and construction methods may influence the building’s geometry and subsequent design decisions. Early design stages are, therefore, the best moment to plan and minimize emissions from products, construction and even end of life. Although the emissions calculation is more precise at later stages, mitigation measures are more difficult to implement in detailed design.

Operational carbon is the CO2 equivalent emissions from the use of a building, including regulated (for heating, cooling, ventilation and lighting) and plug loads (appliances and equipment). However, maintenance, refurbishments and replacements at this stage incorporate additional elements to the construction and, therefore, involve embodied carbon emissions while extending the building’s lifetime.

15

Figure 2.2.3.2. End-of-life scenarios: landfill (LF), landfill with 50% of CLT panels sent for reuse (LF 50% reuse) and incineration (INC). Results are presented relative to the landfilling scenario (O’Connor et al., 2013).

16

The operational carbon should also be a concern at early stages. The design brief, site and climate analysis influence the environmental strategies and inform the concept design. Decisions on the building’s orientation, shape, and constructions have an impact on the control of the climate influence in the building, and therefore in the energy required to provide indoor thermal comfort when it cannot be achieved passively.

A comprehensive design concept should consider the building life-cycle, comprehending embodied and operational carbon emission, rather than looking at each of them separately.

2.2.4. Thermal comfort and annual loads The energy needed to power space conditioning is referred to as “regulated loads” in mechanically controlled buildings. Free-running buildings, in contrast, rely on the sun as a major heat source, and differences in the air pressure for air movement to dissipate excessive heat. Depending on the climate, it is not possible to provide thermal comfort passively during the whole year, but the building design and constructions should minimise the demand for heating, cooling and ventilation. The humans’ adaptability to a wide range of environmental conditions should be also considered as an opportunity to expand the freerunning period in mixed mode buildings.

The thermal experience in buildings is affected by the external and internal conditions. Heat exchange between those two environments is affected not only by differences in the air temperature, but also by the radiation from the sun and other bodies that generate heat indoors and outdoors.

The human body is sensible to the effect of both convective and radiative heat exchanges, which makes the resultant or operative temperature (OT)

more relevant to understand the thermal comfort than the dry bulb temperature (DBT) only, as it is the weighted average of the DBT and mean radiant temperature (MRT). The building shape, orientation and the fabric’s properties have a direct influence in the passive control of indoor thermal comfort, and therefore, in the amount of energy required to manipulate the temperature to acceptable levels throughout the year. The embodied carbon and operational energy of a building are strongly affected by the architectural design, specification of structural systems, constructions and envelopes.

Each orientation offers different conditions of exposure to solar radiation. Solar gains are the global irradiance (W/m2) incident on the surface, comprising the direct and diffuse components.

The building envelope response to radiant heat input is affected by the opaque surface absorptance, which varies depending on the surface material and colour. The heat release to the environment depends on the surface conductance, which is the combination of convective and radiative components.

Additionally, the heat flow rate through the envelope depends on the fabric’s resistance (R) – or its reciprocal, transmittance (U-value) - defined by the conductivity and thickness of all construction layers, and the internal and external surfaces conductance (Szokolay, 2014).

The first measure to control fluctuations in indoor temperatures is controlling the façade exposure to global radiation, as to allow or prevent solar gains according to the exterior temperatures throughout the year and the environmental requirements for indoor activities. The building’s shape and orientation, and also the urban microclimate have a major impact not only on the exposure to radiation, but also to wind, that may offer passive cooling. The potential for heat release through

17

Figure 2.2.3.5. Heat flow inwards through a real wall (continuous line), compared to a “zero-mass� wall of the same U-value (Szokolay, 2008).

18

natural ventilation during the night may be reduced by the urban heat island effect from GHG emissions and the radiation from the surrounding surfaces that heated up during the sun hours. The design of effective shading is markedly important in case the opportunities for ventilation are limited.

The second action to ensure indoor thermal comfort is controlling the heat flow through the fabric. It is influenced by the building compactness, and largely by the envelope properties.

Resistive insulation relies on the still air low conductivity, offering an immediate response to temperature changes. Insulating materials are lightweight porous structures to keep air trapped and still, so that convection doesn’t happen through the construction cavity.

Capacitive insulating materials, in contrast, delay the heat flow and potentially reduce the magnitude of heat transfer through the construction. The material absorbs part of the heat and increase its own temperature before transmitting it to the next layer in the construction. The thermal capacity of massive constructions causes a time lag between the heat input at one face and the heat output on the other face of the envelope (Figure 2.2.3.5). This delay is important to prevent from excessive heat gains during day-time in summer, provided that there is opportunity for night-time heat dissipation.

Otherwise, overheating may occur during sleeping hours and even continuously, if there is a cumulative build-up of heat storage in a sequence of hot days (Rüdisser, 2018).

The physics involved in the dynamic thermal performance are the admittance and the heat capacity. The thermal mass effect is ruled by the thermal admittance, surface factor and decrement factor (CIBSE, 2015).

The specific heat capacity (J/kg.K) is the energy required to increase by 1K the temperature of 1 kg of a given material.

The thermal admittance (W/m²K) refers to the material’s ability to store heat upon variations in the temperature in either sides of a construction. It describes the amplitude of the heat flow caused by a 1K temperature swing. This property is defined by the material heat capacity, density and conductivity.

It is relevant for the layers closer to the internal surface of a construction, so there is less or no significance for thermal mass inner layers or very thick surface layers: only the first 100mm after the exposed surface have an effective role in controlling overheating. However, the thermal mass effect is reduced if the high-capacity material is decoupled from the room hot air (Orme and Palmer, 2003).

Surface factor is the ratio of the rate of heat flow release to the rate of heat flow absorption by a surface. It is associated with the material thermal conductivity and the time lag involved in the heat transfer.

Decrement factor is the ratio between the heat flow through a material and a hypothetical “zero mass” material with the same U-value.

The presence of thermal mass changes the reaction time of the building to temperature fluctuations, so it may influence the thermal comfort, and space heating and cooling loads. For this reason, the thermal mass parameter is part of SAP environmental impact assessment.

The annual regulated loads in a building is dependent on the needs for active heating and cooling, which may be provided through a variety of systems and powered by different possible energy sources and fuels. The conversion between energy and CO2 depends on those mentioned factors.

19

Planted forest, Dorset, UK

20

2.3. An overview of timber constructions Wood contributes to both reducing CO2 emissions – because it replaces carbon-intensive materials - and temporarily capturing carbon (C) from the atmosphere, delaying its release in the form of CO2. If wood is burnt or disposed in landfill, the stored carbon is released, and the sequestration effect is lost. For this reason, the sequestration factor is often excluded from embodied carbon calculations (ICE, 2019) and timber is considered “climate neutral” (IPCC, 2019).

Wood’s end of life can be delayed by reusing the material with few processing steps. It should be first used for structure and designed and built to be dismantled and reused for non-structural purposes.

It can be then reprocessed into smaller pieces and shavings to be used as a raw material for products other than construction. Only as a last option, it should be used as biomass for thermal energy recovery.

This life-cycle expansion delays the release of sequestered carbon. However, if treated with chemical preservatives, wood cannot be reused.

The conditions of wood exposure to weather and xylophages must be considered in the selection of timber species and design of construction details, in order to avoid the use of such hazardous substances that may reduce the environmental advantages of using wood.

Sathre, R. and O’Connor, J. (2010) compared the use of wood and non-wood materials in buildings with the same energy consumption, to estimate the potential GHG savings. They identified that every ton of timber used prevents the emission of 3.9tCO2e from carbon-intensive materials.

2.3.1. Timber building systems: advantages, potentialities and constraints Timber structures are lightweight, compared to concrete frame. It allows for shallower and reduced foundations, meaning less concrete and steel in the building. Replacing carbon intensive materials with wood reduces the building embodied carbon in the production stage and the generation of particulate matters in the construction stage, causing less impact to the site neighbourhood.

The development of engineered wood components minimised the limitation in sawn wood sizes, and the lack of homogeneity and anisotropy - the structural dependency on the wood grain direction.

The use of glue in timber structural elements expanded the potential applicability of this material, as small section elements and species with low mechanical properties can be processed into large structural components. In the end of the 1990’s cross laminated timber panels started to be used for slabs and bearing walls, launching new building typologies in timber structure. Prefabrication technologies integrating building information modelling (BIM), computer aided manufacture (CAM), computer numerical control machines (CNC) and robotics allowed more precision and growth in scale production, making timber more competitive with steel and concrete for the contemporary needs in construction. Research on high-performance connectors and hybrid structures is a key factor to build economically, take advantage of each material’s best properties and make constructions comply with building codes and regulations.

21

y and a strucnot directly g this fact

material – ected by fireection coatg capacity contrast, a will burn on ctural intega fire without ng or coating. ble, but mediately. nel will rom passing

Protective functions

C 1.6 Figure 2.3.1.1. Cross section of a solid timber beam that has been exposed to fire. The charred layer preserves the structural integrity of the centre of the timber cross section (Kaufmann et al., burn 2018).

Material One-dimensional burn Nominal rate ßn rate ß0 [mm/min]

[mm/min]

0.65

0.7

0.65

0.8

0.65

0.7

0.50

0.55

Laminated veneer lumber with a characteristic density of ≥ 480 kg/m3

0.65

0.7

Panels Wood panelling

0.9 1)

Softwood and beech Glued laminated timber with a characteristic density of ≥ 290 kg/m3 Solid wood with a characteristic density of ≥ 290 kg/m3 Hardwood Solid wood or glued laminated timber with a characteristic density of ≥ 290 kg/m3 Solid wood or glued laminated timber with a characteristic density of ≥ 450 kg/m3

22

1)

2.3.1.1. Fire protection The risk of fire is a concern in all types of construction.

Fire safety involves materials combustibility and the fire resistance of building elements.

Fire ignites in buildings due to either failure in technical installations or errors in human activities involving fire, such as cooking, smoking, lighting candles. Combustible materials – not only wood, but other fibres, plastic, insulation, carpets and other textiles – contribute to the fire spread when it breaks out. Although furniture and fittings may be very combustible and have a major impact in early stages of a fire spread, it is not possible to control them through building regulations. It is, therefore, recommended by fire safety codes that emergency escape routes and facades do not have combustible exposed surfaces, unless there is an incombustible layer behind it, such as plasterboards.

Although combustible, wood has a good fire resistance. Timber structural elements can remain stable and prevent the spread of smoke and heat through them. Laboratorial tests proved that the charred surface of wood prevents the element from burning completely and transferring heat through, depending on the surface-to-cross section ratio (Figure 2.3.1.1). Structure international codes recommend, therefore, that exposed timber structure elements be oversized, as to comply with the building regulations requirement that structures must keep the building stability and allow occupants to escape or be rescued.

In contrast, non-combustible materials such as concrete and steel have a poor fire resistance, as their collapse is unpredictable when submitted to such high temperatures.

The 2019 edition of the UK’s Building Regulations – Part B was issued in the light of the Grenfell tower tragedy. It specifies that the building fabric should make a limited contribution to fire growth, including a low rate of heat release, but does not ban claddings or any specific material. It defines a minimum thickness not only for timber (9mm), but also steel claddings (0.5mm) (Ministry of Housing, Communities and Local Government, 2019).

Fire resistance of mass timber panels’ adhesive is currently limited. Exposed CLT panels risk to have their first layer detached because of glue melting during a fire event. While further research is being developed, the industry practice is minimising the exposed CLT surfaces in a room by encapsulating it with non-combustible materials such as plasterboards. According to empirical knowledge from the industry, exposed wood in a room should be limited to two surfaces (Kaufmann et al., 2018).

For instance, if the ceiling is an exposed CLT slab and the floor finish is wood, any timber walls should be encapsulated. This requirement has an impact on the use of wood’s thermal capacity for thermal comfort. Even if its thermal mass is much lower than in mineral materials like concrete, it is higher than lightweight cladding such as plasterboards.

Moreover, the addition of a non-combustible finish layer will also increase the embodied carbon of the construction.

The use of fire-resistant coatings instead does not bring the same safety benefits as the physical barrier of a cladding and their performance may be affected by weathering. Timber structure manufacturers and contractors avoid using them as they don’t improve wood’s combustibility significantly. From an environmental perspective,

23

33% SteelSteel 33%

Textiles 4% Textiles

Cement 26%

Food 3%

Plastics 17%

Paper 2%

Cement 26%

Plastics 17% Metal manufacturing 7%

Wood 1%

Aluminium 6% Metal manufacturing 7%

Other 1% Wood

Aluminium 6%

4%

Food 3% Paper 2%

The iron and steel industry has made big strides to improve energy efficiency but still accounts for between 6–7% of global CO2 emissions.16 Its best promise lies with increasing the extent of recycling, which some studies show as low as 35–40% of steel globally.17 These figures are likely to increase as we transition into a low carbon ‘circular economy,’ in which high-embodied energy materials like steel are repurposed indefinitely, and to ensure we meet global emission-reduction targets.

1%

Other 1%

Figure 2 The above chart shows relative percentages of CO 2 emissions by material in China, home to the world’s largest construction and manufacturing markets.18

Given the high carbon footprint of cement and steel production and the challenges these industries face transitioning, timber is becoming a compelling third option. Timber is one of the few renewable construction materials and, by its very nature, the production of wood via photosynthesis removes CO2 from the atmosphere. Depending on the end-of-life disposal scenario for the wood product, most of this captured carbon can also be sequestered or result in net-zero carbon emissions if burned for biomass energy (assuming a fossil fuel offset).

Figure 2.3.1.2.1. Microscopic structure of wood: tracheids (softwood) and pores (hardwood). In red: spruce, a softwood.

In blue: ash, hardwood 2019).

Trees absorb about two tonnes of aCO to create(Arup, one tonne of their own (dry) mass. In the spring, softwoods 2

like spruce (left) add large cells to carry water up the trunk for quick growth. In the summer, the cells become smaller as the emphasis changes to producing wood for strength. Hardwoods like ash (right) start off in spring with a ring of even larger diameter vessels.19

16

24

Rethinking Timber Buildings

the addition of such chemical components is not a good practice, as it makes reusing and recycling unfeasible, besides adding intensive-embodied carbon substances to wood.

The requirements of building regulations Part B for fire protection involve the control of flame propagation and heat emission, as described below: Requirement B1: when there is a fire, ensure satisfactory means of escape for people.

Requirement B2: inhibit the spread of fire over internal linings of buildings.

Requirement B3: The building must be built such that the premature collapse of the building is avoided and an unseen spread of fire or smoke through cavities is restricted.

Requirement B4: restrict the potential for fire to spread over external walls and roofs.

2.3.1.2. Thermal properties Timber properties vary considerably according to the wood species. Most hardwoods are denser than softwoods. Differences in the trees growth pattern and time is have an impact on the characteristics of the fibre structure.

Softwood species grow faster and conduct water and sap through linear vessels (tracheids), whereas hardwood have a slow growth and pores instead of linear tracheids (Figure 2.3.1.2.1).

Wood is an anisotropic material, which means that its properties vary according to the grain direction.

This characteristic affects not only the mechanical performance, but the moisture absorption and, therefore, heat conduction. The tracheids in softwoods have more capacity to absorb moisture, glue and chemical treatment than the hardwood pores. Engineered wood such as glued laminated timber and cross laminated timber are usually made of softwood as spruce.

Softwoods have lower heat capacity and is lighter.

It is better insulating material, whereas hardwoods have a slightly higher thermal mass.

Some manufacturers claim that mass timber panels have enough thermal mass to provide comfort in summer and classify solid timber buildings as medium-weight constructions. However, they recognize that the high-capacity material should be exposed to provide the thermal mass effect, which is often not possible due to fire safety requirements.

Mass timber structures are mostly made of softwood. Hardwood may provide a larger amount of thermal mass, but the manufacturers are still testing the feasibility of glued laminated hardwood.

Experimental projects in tulipwood, a hardwood, have been built in the UK in the last 3 years (Figures 2.3.1.2.2 to 2.3.1.2.4). One of them is a permanent building, but it is a hybrid structure, and the CLT is limited to the slabs, so it is still not a case study to assess the thermal mass parameter.

25

Figure 2.3.1.2.2. Temporary CLT structure in hardwood (tulipwood): MultiPly - London Design Festival, by Waugh Thistleton Architects (London, 2018). Available from: http://waughthistleton.com/multiply/.

Figure 2.3.1.2.3. Temporary CLT structure in hardwood (tulipwood): The smile - London Design Festival,

by Alison Brooks (London, 2016). Available from: http://www.alisonbrooksarchitects.com/project/thesmile/.

26

Mass timber components exported to the UK are mostly made of spruce, a softwood.

Spruce at 12% moisture content (Bindeholz, 2019) Thermal conductivity:

0.12 W/m.K

Density:

470 kg/m3

Specific heat capacity:

1600 J/kg.K

The disadvantages of doing so are the increase in embodied carbon and potential overweight loads, despite the reduced thickness required to add effective thermal mass. The use of phase change materials embedded in plasterboards may be a mitigating strategy to provide thermal mass and avoid mineral-based materials (Rodrigues, 2009).

Hardwood (CIBSE, 2015) Thermal conductivity:

0.17 W/m.K

Density:

700 kg/m3

Specific heat capacity:

1880 J/kg.K

Architects use to adjust the thermal mass content in a timber building by using a minimum surface of exposed heavyweight materials, usually attached to the ceiling.

Figure 2.3.1.2.4. Permanent CLT structure in hardwood (tupliwood): Maggie’s Oldham cancer centre, by dRMM (Oldham, UK, 2017). Available from: http://drmm.co.uk/projects/view.php?p=maggies-oldham.

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Figure 3.1.1. World map of 90Koppen-Geiger −160 −140 −120 −100climate −80 −60 classification. −40 −20 0 20 Available 40 60 80 from: 100 120http://koeppen-geiger.

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3.

CONTEXT AND PRECEDENTS

3.1. London climate This research investigates the use of mass timber in mid-rise residential buildings in London, United Kingdom (51° 30’ N, 0° 7’ W).

The city is located in a temperate climate zone and, according to Koppen-Geiger classification, it is a warm temperate, fully humid and hot summer climate (Cfb) (Figure 3.1.1).

The temperatures are mostly below the adaptive comfort band, indicating that heating degree days are predominant. In summer, high mean temperatures reach the adaptive comfort band in July and August (Figure 3.1.2). The mostly overcast sky reduces the incidence of direct solar radiation.

Therefore, the diffuse radiation is proportionally important in this climate. The south aspect receives the highest amount of it throughout the year, but the west and east have a larger vertical radiation incidence during summer, because of a larger amplitude in the solar azimuth and lower frequency of cloudy skies in this season.

However, the precipitation patterns are likely to change, with stronger rains in summer.

The sky will be 18% less cloudy, increasing the shortwave radiation in summer (Figure 3.1.3).

A bioclimatic architectural design should consider the climate context, the solar geometry and properties of the building materials to take advantage of the opportunities passive thermal comfort strategies.

During the cold months in London, the combination of high internal heat gains and solar radiation may raise the risk of overheating. However, external temperatures are low enough to remove heat excess through natural ventilation, if needed. The use of thermal mass may increase the heating loads. As the time lag for temperature changes in high heat capacity materials is larger, the heating system will take longer to provide the intended room temperature.

Night-time temperatures in London are low even in summer - except for heatwaves or very few days in the year - so heavy constructions may bring thermal comfort during the warm season. In this period of the year, massive elements behave as a heat sink, absorbing solar radiation during daytime Monthly Average Global Vertical Radiation Monthly Average Global Vertical Radiation Winters will be wetter, and summers will be drier. and releasing it during night-time.

The IPCC and UKCP18 projections for London climate in the medium emissions scenario (A1B) indicate a warmer climate in both summer and winter in 2050. Despite the increase in colder hours, the warmer hours will exceed them by 18%.

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29

Stadthaus stairwell in CLT. Waugh Thistleton Architects, 2009.

30

3.2. Built precedents Hundreds of mass timber exemplars have been built in the UK in the last decade, most of them residential buildings. As low carbon emissions in the timber product stage have been an incentive to the use of wood in construction, publications often include structure embodied carbon data about the projects, comparing it to mostly used and carbonintensive structural systems.

This is explained by the relevance of foundations and structure to the overall embodied carbon calculation in buildings. There are, however, few researches on the overall carbon emissions of timber buildings. The frequency within thermal comfort in free running mode, occurrence of overheating and the operational energy for heating and cooling affect the operational carbon emissions. Reducing operational emissions require improvements in the building design that may include or not more carbon-intensive constructions.

London, simulating four construction scenarios: lightweight, mediumweight, heavyweight and very heavyweight. In the second one, researchers at the Graz University of Technology, in Austria, compared the contribution of four construction methods with distinct thermal mass and other design variables (Ferk et al., 2016). The third study explored two residential typologies, simulating them to different climate zones in the United States. It aimed to assess the energy savings from the CLT thermal mass compared to timber frame typical constructions, considering the same U-values and compliance with ASHRAE (Glass et al., 2013).

The final part of this review summarizes the most detailed research available to date about the thermal performance and annual loads in CLT midrise residential buildings in the UK.

3.2.1. Embodied carbon: CLT buildings in The first part of this review of built precedents aims the UK to provide a background of the carbon emissions related to this building system. It lists representative residential buildings in the UK, their envelope construction and embodied carbon.

The second part presents three theoretical studies. The first one was published by the Timber Research and Development Association (TRADA, 2015) and studies a typical 3-storey house in

The construction industry in the UK has started to explore mass timber structures in mid-rise buildings as it recognizes a range of advantages in the construction stage - for project scale - compared to cast-in-place concrete. The built exemplars below are a selection of representative cases to illustrate the state-of-the-art of CLT residential buildings in the UK.

31

Floor: 15mm Wood Flooring 55mm Screed rior Wall: 25mm Insulation ternit Tile 146mm CLT Floor Panel m Air Gap 75mm Void nsulation 50mm Insulation Wall Panel 1 Layer Gypsum Board sum Wall Floor: Floor: Board 15mm Wood Flooring15mm Wood Flooring 55mm Screed 55mm Screed Exterior Wall: Exterior Wall: 25mm Insulation 25mm Insulation Eternit Tile Eternit Tile 146mm CLT Floor Panel 146mm CLT Floor Panel 50mm Air Gap 50mm Air Gap 75mm Void 75mm Void 70mm Insulation 70mm Insulation 50mm Insulation 50mm Insulation 128mm CLT Wall Panel 128mm CLT Wall Panel 1 Layer Gypsum Board 1 Layer Gypsum Board 2 Layers Gypsum Wall 2 Layers Gypsum Wall Board Board

Section At Exterior Wall

Core: 117mm CLT Wall Panel 40mm Insulation 128mm CLT Wall Panel 50mm Insulation 2 Layers Gypsum Wall Board

Core: Core: 117mm CLT Wall Panel 117mm CLT Wall Pan 40mm Insulation 40mm Insulation 128mm CLT Wall Panel 128mm CLT Wall Pan 50mm Insulation 50mm Insulation 2 Layers Gypsum Wall 2 Layers Board Gypsum Wa

Section At Core

ite Apartments architectural details. Source: Waugh Thistleton Architects

Figure 3.2.1.1. Stadthaus, London. Construction details: lightweight cladding in wood pulp. (Waugh Section At Exterior Wall Section At Core Section At Core Thistleton Architects,Section 2009)At Exterior Wall

5.2.9 Graphite Apartments 5.2.9 architectural Graphite Apartments details. Source: architectural Waughdetails.

Thistleton Source: Architects Waugh Thistleton Architects

55

55

-505 tCO2e

55

Figure 3.2.1.2. (left). Stadthaus, London. Photograph. (Waugh Thistleton Architects, 2009) Figure 3.2.1.3 (right). Stadthaus, London. Plan and section: mass timber elements in yellow (Waugh Thistleton Architects, 2009)

32

CASE STUDIES IN SOLID WOOD ARCHITECTURE

Brick Exterior Wall Brickwork Setback for Shadow Gap Prefabricated Concrete Lintel Matching Brick Brick Soffit with Matching Brickwork

Flat Steel Galvanized and Pre-coated Balustrade

Thermal Insulation

Main Structure of Cross Laminated Timber

Composite Timber

/ Aluminum Figure 3.2.1.4 (left) and 3.2.1.5 (right). Frame Bridport house, London. Plan and Section: the Window System external walls are brick-clad (Karakusevic Carson Architects, 2011).

Composite Timber Frame / Aluminum Door System

Ground Level Access

-896 tCO2e Figure 3.2.1.6. Bridport house, London. building’s southeast aspect is shaded with 5.4.9The Detail wall section and elevation.

Source: Karakusevic Carson Architects balconies (Karakusevic Carson Architects, 2011).

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33

-281 tCO2e Figure 3.2.1.7. Whitmore Road (Waugh Thistleton Architects, 2012).

-424 tCO2e Figure 3.2.1.8. Trafalgar place (dRMM, 2015).

34

-1458 tCO2e Figure 3.2.1.9. Cobalt Place (Allford Hall Monaghan Morris Architects, 2015).

-715 tCO2e Figure 3.2.1.10. Wenlock cross (Hawkins\Brown, 2015).

35

Research Summary Thermal mass in lightweight domestic construction

Research Summary Thermal mass in lightweight domestic construction Research Summary Thermal mass in lightweight domestic construction

Importance of ventilation and shading

The results of this study show that thermal mass in domestic buildings has a negligible effect on overheating during occupied 6 Results hours. However it has also highlighted that if the climate warms Heating demand 6 Results in the future, the risk of overheating may well increase. For this Figure 2 shows annual heating loads for current weather and for reason it is sensible to consider strategies that will mitigate this Heating demand predicted 2050 weather.

It is clear that the warming assumed Figure 2 shows annual heating loads for current weather and for risk and hopefully avoid the need for air conditioning. for 2050 to a Itsignificant reduction in heating demand. predicted 2050leads weather. is clear that the warming assumed Across typesreduction there is very little difference, for 2050 leadsconstruction to a significant in heating demand. with One of the difficulties of naturally cooling a domestic dwelling heavyweight construction tending to have slightly higher heat is in providing secure ventilation. When residents are in the Across construction types there is very little difference, with demand.

This is because thermally construction building this can be achieved through window opening but it heavyweight construction tending to havelightweight slightly higher heat responds more quickly to the intermittent heating schedule is unlikely that windows can be left open while the building demand. This is because thermally lightweight construction Figure 5 Temperature profiles summer forheat bedroom 1 In other (morning afternoon), leading to days lower demand. is unoccupied. Also, this strategy relies on natural ventilation, responds more and quickly toover the two intermittent heating schedule across construction typesthe heating switches on it initially needs to supply words, when only 3achieve so many air changes hour. A1 spent over a Figure Percentage of occupied hours inper bedroom (morning and afternoon), leading to lower heat demand. In other which can range of temperatures across different construction types to the switches heavier-weight cases needs to bringtothe thermallypossible alternative is to include some mechanical ventilation words,more whenenergy the heating on it initially supply Figure 3 Percentage of occupied hours in bedroom 1 spent over a heavy construction elements cases up to temperature than it does inwhich, low fan power, willdifferent be substantially less energy rangewith of temperatures across construction types more energy to the heavier-weight to bring the thermally lightweightelements case. up to temperature than it does in intensive than air conditioning but can make an impact on high heavythe construction temperatures. the lightweight case.

Another strategy is to provide solar shading. For example this could be in the form of overhangs or brise soleil, which will cut down heat gains from the sun. This has the benefit of requiring no operational energy and prevents heat from entering the building, rather than trying to remove it later.

Figure 6 Overheating risk for bedroom 1 and living room across different construction types for current weather

To investigate these strategies, increased ventilation and solar shading were applied to the domestic dwelling used in this Figure 4 Percentage of occupied hours in bedroom 1 spent over a study (Figure 8).

range of temperatures across different construction types for 2050

Figureclimate 4 Percentage of occupied hours in bedroom 1 spent over a This finding is demonstrated in Figure 7 which shows a very range8 of temperatures across different construction types for 2050 Figure shows that both strategies lead to a significant Research Summary small increase in percentage of occupied hours between Figure 3.2.2.1 (left). demand the whole house Figure 2 Heating demand for the Heating whole house across for different climateacross different construction types (TRADA, 2015). reduction in internal temperatures. It is interesting to note that The risk of overheating in the bedroom is identical for 22–25°Cconstruction (lightweight and mediumweight Thermal types mass in lightweightcompared domestictoconstruction Figure 2 Heating demand for the whole house across different solar shadingover tends reduce the temperatures duringdifferent the day Figure 3.2.2.2.

Percentage of occupied hours in a bedroom a to range of temperatures across lightweight, mediumweight and heavyweight constructions heavyweight), which all but disappears when considering construction types The risk of overheating in the bedroom is identical for it reduces the solar gain during daytime), whereas increased construction types (simulation projected to 2050 (as climate) (TRADA, 2015). because although the and lightweight bedroom experiences slightly temperatures above 25°C. lightweight, heavyweight Overheating ventilation givesmediumweight a more marked reduction duringconstructions the night higher peak temperatures during the day, it cools down because although lightweight bedroom experiences slightlyfar more There are many definitions of overheating. The approach takenwhen cooler ambientthe air is Overheating Importance ofavailable. ventilation and shading quickly in the evening.

This is demonstrated by Figure 5, which higher peak temperatures during the day, it cools down far more study was to consider temperatures during occupied There by arethis many definitions of overheating.

The approach taken The results of this study show that thermal mass inreaching domestic lightweight mediumweight buildings quicklyshows in thethe evening.

This isand demonstrated

by Figure 5, which assumed to be 23:00–07:00 daily for by thishours, studywhich was towere consider temperatures during occupied buildings hasthat a negligible effect onthan overheating during occupied a temperature is slightly higher the heavyweight shows the lightweight and mediumweight buildings reaching andassumed 17:00–23:00 weekdays, 07:00–23:00 hours,bedrooms which were to be 23:00–07:00 daily for weekends hours. it has alsoinhighlighted thatThe if the climate warms case butHowever cooling off quickly the overnight a temperature that is slightly higher thanevening. the heavyweight for living rooms. bedrooms and 17:00–23:00 weekdays, 07:00–23:00 weekends in the future,are thevery risk similar, of overheating may well increase.

For this temperatures with the lightweight case but cooling off quickly in the evening. The overnightcase for living rooms. reason itinisthe sensible totemperature consider strategies thatofwill mitigate this resulting at the end One way to consider overheating is to look at a frequency plot of temperatures are verycoolest similar, with the lightweight casethe night. risk and hopefully avoid the need for air conditioning. exceeded temperature for aiscertain Figure 3 below in the coolest temperature at the end of the night.

One way to consider overheating to lookroom. at a frequency plot ofshows resulting The ability of the lightweight construction to lose heat at night the percentage of occupied hours for which certain temperatures exceeded temperature for a certain room. Figure 3 below shows Onethese of the difficulties ofso naturally cooling a domestic dwelling over periods is effective considered The ability of the hot lightweight construction tothat, losewhen heat at night are exceeded for the master bedroom (bedroom 1). the percentage of occupied hours for which certain temperatures is in providing ventilation. When are in the across wholesecure overheating the residents lightweight over these hotthe periods isyear, so effective that,inwhen consideredbedroom is are exceeded for the master bedroom (bedroom 1). building this can be achieved through window opening but it than the heavyweight Findings indicate that there is very little difference acrosslower the whole year, overheatingconstructions. in the lightweight bedroom is is unlikely that windows can be left open while the building Figure 7 Percentage of occupied hours spent over certain in overheating in this caselittle between lightweight, lower than the heavyweight constructions.

Findings indicate thatrisk there is very difference temperatures across different construction types for the living room Figure 5Figure Temperature profiles over two summer days for bedroom 1 Figure 6 alsocertain demonstrates that therelies risk of in the is unoccupied. this strategy onoverheating natural ventilation, 3.2.2.3 (left). construction Percentagesolutions. of occupied over temperatures across different Figure spent 8 Temperature profileAlso, of bedroom 1 over a two-day period for mediumweight or heavyweight This hours within1990s weather across construction types overheating risk in this case between lightweight, living (fraction ofthat occupied above 27°C) is very construction types for the living room with 1990svarious weather (TRADA, 2015). can only achieve sothemany air changes perinhour.

A low shading and ventilation strategies Figure 6which alsoroom demonstrates riskhours of overheating the pattern is or maintained when consideringsolutions. the predicted mediumweight heavyweight construction This 2050 (less than 1%) for all forms of construction.

In the lightweight possible alternative is to include some mechanical ventilation living room (fraction of occupied hours above 27°C) is very low albeit with a slightly higher temperature distribution Figure 3.2.2.4 (right).

Temperature of a bedroomcase over for various shading andenergy patternclimate, is maintained when considering the predicted profile 2050 thisawith istwo-day primarily because lightweight construction responds which, fanperiod power, will be substantially less (less than 1%) for alllow forms of construction.

In the lightweight across board (Figure 4). temperature ventilation strategies (TRADA, 2015). climate, albeitthe with a slightly higher distribution very well to window opening, allowing cooling. intensive than air conditioning but can make an impact case this is primarily because lightweight construction respondson high across the board (Figure 4). © TRADA Technology Ltd 2013 5 temperatures. very well to window opening, allowing cooling.

36 Another strategy is to provide solar shading. For example this © TRADA Technology Ltd 2013 4 could be in the form of overhangs or brise soleil, which will cut © TRADA Technology Ltd 2013 4 down heat gains from the sun. This has the benefit of requiring

3.2.2. Operational carbon: the influence of the thermal mass and other design variables The Timber Research and Development Association studies the thermal mass in lightweight domestic constructions, compared to London typical masonry constructions (TRADA, 2015). The analysis investigated the risk of overheating, and heating and cooling demands using EDSL TAS. The analysed typology is a typical semi-detached two-storey house with an envelope thermal transmittance of 0.28W/m2.K. The thermal mass parameter varied according to the following construction scenarios. The lightweight construction is timber frame. The heavyweight is a typical brick and block insulated cavity wall, internally rendered with wet plaster over mediumweight concrete block.

The mediumweight construction is also a typical cavity wall, but with plasterboard over lightweight concrete blocks internally. The annual heating loads to keep the living room temperature at 22oC and bedrooms at 18oC in the different construction scenarios is very similar (Figures 3.2.2.1 and 3.2.2.2). Despite presenting roughly the same risk of overheating, the lightweight construction shows more frequent operative temperatures above 22oC, a larger variation in temperatures, with higher peaks, and cools down quicker than the massive ones (Figure 3.2.2.3). The research finishes by investigating the impact of increased ventilation and shading, concluding that those measures provide more significant improvements in the operative temperatures than offered by the increase in thermal mass (Figure 3.2.2.4).

The Laboratory for Building Science at Graz University of Technology studied the influence of the structural type, natural ventilation and shading in the thermal response of a theoretical residential building in Graz, Austria, during summer. They ran dynamic thermal simulations in DesignBuilder 4.2 with EnergyPlus 8.1, and compared solid steelreinforced concrete, solid brick, cross laminated timber and timber frame panels. Those four construction base scenarios were then combined

with changes in other design variables - shading and natural ventilation – by testing both increasing and reducing them. The analysed outputs were: average operative temperatures, number of hours in which the temperature exceeded 27oC, number of nights in which the temperature exceeded 25oC, and average operative temperatures during night-time. The main finding is that the thermal comfort in the different constructions is very similar if shading and ventilation are adequately provided (Figure 3.2.2.5). The difference between the constructions’ response is more significant if shading and ventilation are reduced (Figure 3.2.2.6).

In this case, constructions with lower thermal mass are prone to higher risk of overheating the massive ones (Figures 3.2.2.7 and 3.2.2.8). It indicates that the thermal comfort in summer, in the studied climate, is more affected by the control of solar gains and heat dissipation than by the building fabric properties (Figure 3.2.2.9). The operative temperatures in a warm week temperature profile indicate that the lighter the structure, the larger the fluctuation in temperature. Nonetheless, the temperatures in the simulated construction scenarios differ by only decimals, provided that the external temperature is below 25oC. If it raises above 25oC, the temperature difference between the concrete and CLT constructions may reach 1K, even with increased shading and ventilation (Figure 3.2.2.10).

The research concluded that, considering the low U-values required by the current building regulations, the envelope mass has a negligible influence of decimal degrees in the variation of indoor OT during the warm season compared to the impact of heat dissipation through natural ventilation and heat gains through solar radiation (Ferk et al., 2016).

The heat storage and transfer in CLT buildings is also explored in the “CLT Handbook”, published in 2013 by Canadian and American institutions involved in research and development of the forest and timber construction sector. The study simulates and compares the annual energy required for space conditioning in two residential building typologies:

37

26 Abb. 13: 30 °CTemperaturverlauf 30 °Cim heißesten Raum für den Fall „erhöhte 28 Beschattung, er28 27 °C-Kriterium höhter Luftwechsel“ 27 °C-Kriterium 26 26 Abb. 11: Temperaturverlauf Abb. 11: im heißesten Raum Temperaturverlauf für den Ausgangsfall im heißesten Raum „base case“ für den Ausgangsfall „base case“

24 24

24 22 20 25.7.2003

22 außen external temperature 22 Massivbau – Stahlbeton reinforced concrete structure 20 Massivbau – Ziegel brick construction 20 Holzbau – Brettsperrholz cross-laminated timber 25.7.2003 26.7.

Holzrahmenbau timber frame 25.7.2003 26.7.

30 °C 30 °C 29 °C 28 28 27 °C-Kriterium 27 27 °C-Kriterium 26 26 25 Abb. 12: 24 Temperaturverlauf im Abb. 12: 24 heißesten Raum für Temperaturverlauf im 23 22 den Fall „verringerte heißesten Raum für 22 Beschattung, verrinden Fall „verringerte 21 gerter Luftwechsel“ Beschattung, verrin20 gerter Luftwechsel“ 20 1925.7.2003 25.7.2003 15.6.2003

26.7.

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Tagesverläufen. Wiederum liegen die höchsten und 27.7.

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30.7. die niedrigsten Werte auf der Temperaturverlaufs27.7.

28.7.

29.7.

30.7. kurve der leichtesten Bauweise. Sehr gut zu sehen sind die raschere Abkühlung der leichteren Konstruktionen infolge einer Wetteränderung Anfang Juli und die darauf folgende raschere Erwärmung in der zweiten Monatshälfte.

Interessant ist auch eine Gegenüberstellung der Mittelwerte der Temperaturen über den gesamten dargestellten Zeitraum (zwei Monate). Diese liegen beim „base case“-Szenario für alle Bauweisen im Bereich z wischen 23,1 und 23,2 °C und damit wieder bemerkenswert eng beieinander. Hinsichtlich der

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zeitli chen Verteilung zeigt sich im betrachteten 31.7.

1.8.

Zeitraum eine leichte Asymmetrie, weil die Tempe31.7.

1.8. raturen des Holzleichtbaus sogar während 55 Prozent der Zeit unter jenen der Stahlbeton-Konstruktion liegen.

Temperaturstatistik Um eine Vergleichbarkeit der zeitlichen Ausdehnung der einzelnen Temperaturniveaus zu ermöglichen, wurde eine sogenannte Boxplot-Auswertung durchgeführt. Bei dieser werden die stündlichen Abb. 14: Temperaturwerte sortiert und anschließend so Gleitende 24-Stun unterteilt, dass jeweils vier zeitlich gleich große

30.7.

30.7.

31.7.

31.7.

1.8.

1.8.

14.8.

den-Temperaturmittel im heißesten Raum für den Ausgangsfall „base case“

4.8.

Figure 3.2.2.5. Increased shading and ventilation: 15.7. the response of25.7. light and heavyweight structures is similar (Ferk et al., 2016).

30 °C

30 °C 29 °C 28 28 27 °C-Kriterium 27 27 °C-Kriterium 26 26 25 Abb. 13: 24 Temperaturverlauf Abb. 13: 24 im heißesten Raum Temperaturverlauf 23 22 für den Fall „erhöhte im heißesten Raum 22 Beschattung, erfür den Fall „erhöhte 21 höhter Luftwechsel“ Beschattung, er20 höhter Luftwechsel“ 20 1925.7.2003 25.7.2003 15.6.2003

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14.8.

Abb. 15: Gleitende 24-Stunden-Temperaturmittel im heißesten Raum für den Fall „verringerte Beschattung, verringerter Luftwechsel“

Figure 3.2.2.6. Reduced shading and ventilation: the amplitude of temperature swings is larger in außen außen Massivbau – Stahlbeton lightweight structures (Ferk et al., 2016).

Massivbau – Stahlbeton Massivbau – Ziegel 29 °C Massivbau – Ziegel Holzbau – Brettsperrholz 27 Holzbau – Brettsperrholz Holzrahmenbau Holzrahmenbau 25

Tagesverläufen. Wiederum liegen die höchsten und zeitli chen Verteilung zeigt sich im betrachteten Tagesverläufen. Wiederum liegen die höchsten und zeitli chen Verteilung zeigt sich im betrachteten die niedrigsten Werte auf der TemperaturverlaufsZeitraum eine leichte Asymmetrie, weil die Tempedie niedrigsten Werte auf der TemperaturverlaufsZeitraum eine leichte Asymmetrie, weil die Tempekurve der leichtesten Bauweise. Sehr gut zu sehen raturen des Holzleichtbaus sogar während 55 Prokurve der leichtesten Bauweise. Sehr gut zu sehen raturen des Holzleichtbaus sogar während 55 Prosind die raschere Abkühlung der leichteren Konzent der Zeit unter jenen der Stahlbeton-Konstruksind die raschere Abkühlung der leichteren Konzent der Zeit unter jenen der Stahlbeton-Konstrukstruktionen infolge einer Wetteränderung Anfang tion liegen.

23 struktionen infolge einer Wetteränderung Anfang Juli und die darauf folgende raschere Erwärmung in tion liegen.

Juli und die darauf folgende raschere Erwärmung in der zweiten Monatshälfte.

Temperaturstatistik 21 der zweiten Monatshälfte.

Temperaturstatistik Interessant ist auch eine Gegenüberstellung der Um eine Vergleichbarkeit der zeitlichen AusdehInteressant ist auch eine Gegenüberstellung der Um eine Vergleichbarkeit der zeitlichen AusdehMittelwerte der Temperaturen über den gesamten nung der einzelnen Temperaturniveaus zu ermögli19 Mittelwerte der Temperaturen über den gesamten dargestellten Zeitraum (zwei Monate). Diese liegen nung der einzelnen Temperaturniveaus zu ermöglichen, wurde eine sogenannte Boxplot-Auswertung dargestellten Zeitraum (zwei Monate). Diese liegen chen, wurde eine sogenannte Boxplot-Auswertung beim „base case“-Szenario für alle Bauweisen im durchgeführt. Bei dieser werden die stündlichen 15.6.2003 25.6.

5.7.

15.7.

25.7.

4.8.

14.8. beim „base case“-Szenario für alle Bauweisen im Bereich z wischen 23,1 und 23,2 °C und damit wieder durchgeführt. Bei dieser werden die stündlichen Temperaturwerte sortiert und anschließend so ereich z wischen 23,1 und 23,2 °C und damit wieder Temperaturwerte sortiert und anschließend so unterteilt, dass jeweils vier zeitlich gleich große Figure Bbemerkenswert eng beieinander. Hinsichtlich der 3.2.2.10.

Summer profile: the temperature swing amplitude in heavyweight structures is lower than bemerkenswert eng beieinander. Hinsichtlich der u

in lightweight. The temperatures in CLT construction may nterteilt, dass jeweils vier zeitlich gleich große reach 1K above the concrete construction, even

under increased ventilation and shading conditions (Ferk et al., 2016).

Abschnitte entstehen. Die hierbei entstehende zen38 trale Linie zeigt damit den Median-Temperaturwert an. Dieser markiert jene Temperatur, die jeweils in der Hälfte der Zeit unter- bzw. überschritten wird.

Der zentrale breite Streifen markiert damit wiede-

1.

zeigt die Temperaturstatistik der Mittelwerte aller Räume an, das zweite in Abbildung 18 stellt die Temperaturen des heißesten Raums statistisch dar.

Sehr gut zu sehen ist, dass ebenso wie die Temperaturmittelwerte auch die Temperaturmedianwerte,

Abb. 16: Gleitende 24-Stun den-Temperaturmittel im heißesten Raum für den Fall „erhöhte Beschattung, erhöhter Luftwechsel“

überstellung der speicherwirksamen Masse unterschiedlicher Bauweisen

Massivbau desimulationen von einer Vielzahl von RandbedinZiegel

gungen und komplexen Zusammenhängen abhängig sind, wurden zusätzlich Berechnungen der sogenannten speicherwirksamen Massen anhand der Normenverfahren durchgeführt. Ausgehend von den vier Bauweisen der Gebäudesimulationen wura den jeweils drei Untertypen definiert. Die speichertwo-storey single family house and a four-storey multi-unit building. To identify the impact of wirksame Masse eines Modellraums dieser zwölf Vathe solid wood thermal mass in the heating and rianten wurden mit unterschiedlichen Methoden cooling loads in different climates, each building berechnet und einander gegenübergestellt.

uweise praktisch unab0). Der Energiebedarf durch günstige Benkriterien wurden die aßgeblich beeinflusst nen Simulationen sich die Fallunteraturmarken hin untererhöhter Luftwechsel“ ssere Aussage zu erlüftung bezieht. zahl der Stunden ll angenommen, dass tive Temperatur über en „Raumtemperahlere Außenluft“ und Überschreitungsstune Fensterlüftung zur uweise abhängigen Folglich ergeben sich nehmbar als bei den increased shading energiebedarf. and ventilation e Abbildung 7). Gut nnen, dass die Bauincreased ventilation ser Betrachtungsweise matisierung praktisch en und die B e s chatincreased shading nergiebedarf zeigt. markanteren Einfluss base case ergieeinträge durch erschiede. Bei funkwerden unmittelbar reduced ventilation nzept und effektiver siert. Die speicherreduced shading len Bauweisen, die es wird deshalb nicht reduced shading unter 27 °C zu halten. h nachts auch nicht and ventilation d auch hier wieder r Bauweise abhängige e unter den vier Baudeshalb nicht relevant.

Wärmeaufnahme 1 Y11 = –––– 2

T1

14 15

Da die Ergebnisse der hier durchgeführten Gebäu-

Klimaanlagen erfolgen speicherwirksamen ritt werden die beiden Rolle. Allenfalls kann nkerten Kriterien peicherwirksame Masse er Anwendung eines il nach Zeiten reduziergigen TemperaturB. während Wochenenden Tagestemperatur) eine höhere Leistung eine maximale Raumphase notwendig erschritten werden. her, reak tionsschneller rd zusätzlich geforstechnisch geringere r in der Zeit von 22 icherwirksame Massen C unterschreiten muss. ere etwa bei einem ert, dass bereits eine eitig für eine langhreitung oder Übernnen. peraturmarken für die matisierten Geschosng des Kriteriums h demgemäß, dass der

T2

1

zuschnitt attachment

e mit hohem Fenster Erwähnenswert ist llem die west- und erhitzung neigen, weil nfalls der solare Einite geringer ist als auf auch Abbildung 26).

en sich durch die ge e sich im Zusammenrgetisch günstig oder

Simulationsergebnis Büronutzun zuschnitt Exkurs: Normenberechnung

Exkurs: Normenberechnung und GegenMassivbau Stahlbeton

mperaturen bezüglich sen, so sind kaum

Dynamische Wärmeaufnahme for the two-storey and 5% for the four-storey

T1 predominantly T2 building. In hot or cold climates, the CLT thermal mass provided less savings than in the 2 temperate 1regions (Figures 3.2.2.11 and 3.2.2.12).

The study attributed the smaller savings in the fourFlächenbezogene storey building to its higher internal heat gains and wirksame compactness (Glass et al., 2013).

1 Y12 = ––––

was simulated in two construction versions, timber Holzbau frame and CLT, and in nine different locations in Brettsperrholz Theorie the United States. Both constructions followed the In der Bauphysik werden die dynamisch-thermi schen Wärmekapazität U-value recommended by ASHRAE. Eigenschaften von Bauteilen insbesondere mittels The three studies lead to the conclusion that the der nebenstehenden Kenngrößen beschrieben 1 The warm temperate climate cities (Atlanta building shape and orientation has a major impact = ––– | Y11 – Y12 | (siehe en 13786 [9]).recorded the most significant 1on and Sacramento) the energy required for space conditioning in Diese werden aus den Wärmeströmen abgeleitet, energy savings in space conditioning related to T1 response T 2 to the climate. The control of heat gains die durch einen im 24-Stunden-Intervall periodisch the introduction of CLT thermal mass. In those and losses Abb. 6: through solar radiation and natural schwankenden, sinusförmigen Temperaturverlauf Temperaturlocations, diurnal temperatures are higher 1ventilation were identified as major concerns to hervorgerufen werden. Die Kenngrößen der Wärmemittelwerte der throughout the year and there is a significant provide thermal comfort passively or at low energy aufnahme werden üblicherweise mittels komplexeinzelnen Zonen number of heating and cooling design days. The 22,5demand, as long as the building envelope complies 20 20,5 21 21,5 22 Flächenbezogene Holzbei den vier wertiger Zahlen angegeben. Dies gestattet es, magnitude of energy savings in heating was similar with the transmittance and air tightness specified speicherwirksame Masse Gemittelte operative Temperatur [°C] rahmenbau Bauweisen neben der Amplitude auch die Phasenverschiebung todes Wärmestroms zu beschreiben. Die dynamische the energy reductions for cooling, around 10% (önorm in building regulations. b 8110-3)

Wärmeaufnahme beschreibt jenen Wärmestrom, der m = –––– durch eine Temperaturschwankung an der gegenc0 der Ziegelbauweise jene der Stahlbetonbauweise w,B,AAbb. 9: Anzahl an Überschreitungsnächten >25 °C – Wohnnutzung Abb. 7: Anzahl der Überschreitungsstunden > 27 °C – Wohnnutzung überliegenden Seite des Bauteils hervorgerufen wird. übertrifft. Dies lässt sich mit dem konkreten Wetterc 0 = 1046,7 J⁄ (kg.K) Die flächenbezogene wirksame Wärmekapazität verlauf des Simulationsjahrs erklären und ist nicht verr. Beschattung u. Luftw verr. Beschattung u. Luftwechsel ergibt sich durch Integration der Wärmeströme von bezogen auf Normalbeton zu verallgemeinern. Die „Reaktionszeit“ des Ge- verringerter Luftwechsel verringerter Luftwechsel beiden Seiten des Bauteils und beschreibt somit das bäudes in Ziegelbauweise, auf die wir später noch verringerte Beschattung verringerte Beschattung Vermögen des Bauteils, bei einer schwankenden eingehen werden, war hier in einer entscheidenden, base case base case Umgebungstemperatur Wärme aufzunehmen und spezifischen Hitzephase offenbar ungünstig. wieder abzugeben. Je höher dieses ist, desto mehr erhöhte Beschattung erhöhter Luftwechsel ist das Bauteil in der Lage, Schwankungen der InnenSchlaftemperaturen erhöhter Luftwechsel erhöhte Beschattung raumtemperatur zu reduzieren. Wesentlich ist jedoch, Die Intention des 25 °C-Unterschreitungskriteriums erh. Beschattung u. Luftwechsel erh. Beschattung u. Luftwe dass hierzu auch ausreichend kühlungswirksame Luft der önorm b 8110-3 ist es, eine Aussage über die 0 5 10 15 20 25 30 35 d 0 50 100 150 200 250 300 350 400 450 500 h an das Bauteil gelangt. Das Bauteil wirkt als Wärme„Schlafqualität“ im betrachteten Raum zu treffen. puffer: Bei Temperaturen über der Durch s chnittsDas Kriterium ist aber sehr spezifisch, weil zum Be- Massivbau – Stahlbeton Figure 3.2.2.7.

Exceedance hours above 27°C: the response of light and heavyweight structures is similar Massivbau – Stahlbeton Massivbau – Ziegel Holzbau – Brettsperrholz Holzrahmenbau tempe r atur wird dem Innenraum Wärme ent zogen, spiel ein Temperaturverlauf, der lediglich um 5 Uhr Abb. 10: Mittlere operative Temperatur im Zeitraum von 22 bis 6 Uhr Massivbau – Ziegel under increased ventilation and shading conditions (Ferk et al., 2016). bei Temperaturen darunter wird die Wärme wieder früh eine operative Temperatur von 24,9 °C aufweist, zu dessen Erfüllung bereits ausreicht. Wie hoch die

Holzbau – Brettsperrholz

FigureTemperaturen im Rest der Nacht waren, spielt in 3.2.2.8. Number of nights above 25°C: the response of light and heavyweight structures is similar Holzrahmenbau underdiesem Fall keine Rolle. Um auch hier eine etwas increased ventilation and shading conditions (Ferk et al., 2016).

verr. Beschattung u. Luftw verringerter Luftwechsel

Optimierung ist es verringerte Beschattung nschutz sowie eine objektivere Darstellung zu finden, wurden für die increased ventilation verringerte Beschattung base case chanische Kühlung sieben Simulationsfälle zusätzlich die Mittelwerte Fällen möglich, eine increased shading erhöhte Beschattung der operativen Temperaturen in der von der Norm verringerter Luftwechsel reinforced concrete structure und einbruchssichere vorgegebenen Zeit von 22 bis 6 Uhr gebildet (siehe base case base case brick construction erhöhter Luftwechsel o sollte die kühlungsAbbildung 10). cross-laminated timber reduced ventilation erhöhte Beschattung erh. Beschattung u. Luftwe ktion des EnergieDas Bild ähnelt jenem der bereits präsentierten timber frame 18,5 19 19,5 20 20,5 21 21,5 22 22,5 23 23,5 °C erhöhter Luftwechsel reduced shading In Ballungszentren Temperaturmittel, jedoch sind Unterschiede bezüg als außerhalb, da 27 kWh⁄ m 2 15 lich der Bauweisen kaum vorhanden. Am deutlichs17 19 21 23 25 gen der zu erwartenten wahrnehmbar sind sie im eben besprochenen Massivbau – Stahlbeton nnächten weniger Abb. 20: Kühlenergiebedarf der einzelnen Bauweisen bei Überhitzungsfall, bei welchem die leichteste BauFigure 3.2.2.9. Energy requirement for cooling (kWh/m2): the response of light and heavyweight structures weise tendenziell die geringsten Temperaturen zwar in spezifischen Tagesperioden die höchsten is den Simulationsfällen mit Klimaanlage in kWh⁄ m similar under increased ventilation and shading conditions (Ferk et al., 2016).

2

zeigt. Dies erklärt sich durch die schnellere Reaktion der leichteren Bauweise auf den nächtlichen, kühlenden Luftwechsel.

Temperaturverläufe Die Zusammenhänge, die zum eben dargelegten Verhalten der Temperaturmittelwerte und Über-

Tagestemperaturen erreicht, ebenso aber meist auch die tiefsten Temperaturen der Nacht erzielt.

Der dominierende Effekt, der von der speicherwirk- 39 samen Masse hervorgerufen wird, ist somit eine „geänderte Reaktionszeit“ des Gebäudes auf Wärmeeintrag durch solare Einstrahlung oder äußere Temperaturschwankungen. Bei der Erwärmung über

Massivbau – Ziegel

Holzbau – Brettsperrhol Holzrahmenbau

Figure 3.2.2.11. Space conditioning energy savings in a CLT two-storey single-family house in the US (Glass et al., 2013).

40

3.2.3. Thermal performance and annual loads in mid-rise CLT buildings in London Adekunle, Holmes and Nikolopoulou published “A comparative simulation of thermal performance in high-rise structural timber buildings”, where two buildings in the London Borough Hackney are analysed: Stadthaus and Bridport House. An overview on this projects can be found in section 3.2.1 of this reserach. Their thermal performance was analysed considering the hottest summer months, July and August.

The research’s outcome is that a variety of aspects influences the thermal comfort, despite the proven contribution of low mass external walls in CLT buildings. The studied cases have a similar CLT wall core, but differences in urban context and other design aspects led to distinct indoor thermal conditions. Factors that interfere in the units’ exposure to solar heat gains are: -Building geometry: typologies and orientation -Urban context: buildings and other elements in the surroundings -Presence or absence of balconies that perform as shading devices

Factors that interfere in the heat exchange are: -Units geometry: floor area, floor-to-ceiling height, window-to-wall ratio -Building envelope properties: fabrics construction, window properties -Natural ventilation potential: aperture size The study simulations predict overheating at daytime in hottest days and cold discomfort in coldest summer nights. However, the difference between the results of the two buildings suggest that the latter mentioned factors shall be considered to achieve a lower OE, if the timber structure is to be used as a low EC structural solution. The introduction of thermal mass elements is a key design decision to provide adequate thermal comfort passively.

The researchers also conducted a post-occupancy evaluation of both buildings during summer and winter, including comfort surveys and monitoring of the internal environment. There was an expressive majority of occupants reporting that they feel too warm or hot in summer 81% in Bridport and 70% in Stadthaus - whereas in winter, most responded they feel neutral.

Figure 3.2.2.12. Space conditioning energy savings in a CLT four-storey residential building in the US (Glass et al., 2013).

41

42

4.

ANALYTIC WORK

4.1. Methodology In the last fifteen years dozens of multi-storey timber constructions have been built in London, making the UK one of the leading countries to adopt cross-laminated timber. The country is committed to reduce its carbon emissions in the building sector, and as the Building Regulations Part L become stricter, the embodied carbon accounts for a greater proportion in buildings emissions.

This analytic study consists in the assessment of embodied carbon and operational energy for space conditioning in a CLT mid-rise residential building. It is, then, compared to typical concrete and masonry constructions with the same U-value as the base case. An existing building in mass timber was selected as a base case, and four other construction scenarios were simulated.

The embodied carbon of each scenario was calculated according to a recognized cradle-togate database developed for the construction of new buildings in the UK, the Inventory of Carbon & Energy, ICE (Jones, C., Hammond, G., 2019). The construction stage was excluded from the analysis, as it requires assumptions on the construction methods, site logistics, resources and waste management. The end of life stage was also excluded, as there is a wide range of possibilities for each material. A comprehensive analysis of this stage requires a research about current and projected technologies for recycling, disposing, and energy recovery. Including it would expand the study beyond its technical field.

The ICE database contains two sections for timber emissions: including carbon storage or excluding it. This is because of the considerations about the end of life stage. This research explored both possibilities.

The study analyses the embodied and operational carbon in a typical floor of the CLT mid-rise residential building. The envelope is analysed

separately, as it mediates the indoor and outdoor environments, and therefore have a major impact on the energy demand. Although foundations account for a fair volume of concrete, this structural element is excluded from this research, as a proper comparison would require structural calculation.

The operational carbon corresponds to emissions from the use stage. This study is focused on the energy demand for space conditioning, the regulated loads. Artificial lighting and plug loads were not included, as they are topics for an expanded research field that comprises behaviour, social development trends, technology development and affordability.

The analysis was based on the energy modelling in EDSL TAS Engineering. Three building operation modes were simulated for each construction scenario: free-running, mechanical and mixed mode. The relevant outputs are the annual loads, frequency of adaptive thermal comfort and risk of overheating. The radiant component in each construction was assessed through the temperature profile of a cold week of January and a warm week in July.

The simulations were carried out for four flats to study the effect of different conditions of solar radiation in the north, south, west and east aspects.

The thermal analysis is focused on the rooms that are occupied for longer periods: combined living room/kitchens, and bedrooms.

The internal gains profile, temperatures for aperture control and thermostat set points were based on CIBSE Guide A (2015) and CIBSE TM59 (2017).

The analytic work finishes by comparing the results for embodied carbon and operational energy of the hypothetical scenarios against the base case, indicating the advantages and disadvantages of each construction.

43

Figure 4.2.1. Dalston Works, London. Designed in 2014 and completed in 2017 (Waugh Thistleton Architects, 2019) 44

4.2. The case study This research analyses an emblematic example of mass timber building in London, recently built and a milestone for the CLT industry.

The case study is Dalston Works (Waugh Thistleton Architects), in the London Borough of Hackney (Figure 4.2.1). Completed in 2017, it is currently the world’s largest pure CLT-structure, in terms of wood volume. This building system has been adopted by the architects and developers in many projects, as the construction process is faster than typical works, produces less waste on site and requires less workers, electricity, and water.

According to the architects, 2,325 trees and a wood volume of 4,649m³ were used to complete the 14,500m² building. Considering the renovation rate of a temperate climate forest, it takes three hours to regrow this number of trees. The architects also estimate that this number is equivalent to less than three trees per occupant.

Despite Hackney’s incentives to reduce carbon emissions in new developments, the reasons

behind the choice of building system are not only environmental. The Elizabeth Line crosses the plot’s underground, limiting the type and depth of foundations, and the weight above it.

The lightweight timber structure allowed to build as high as five to ten stories above a raft foundation, making it possible to deliver 40% more units 121 apartments, instead of 86 (Figure 4.2.2), plus 2,500m² of commercial spaces in the ground floor.

Besides complying with the Crossrail safeguard zone requirements, the shallow foundation required significantly less concrete, reducing the number of deliveries during construction by 80 per cent.

Although there is no exposed timber either external or internally, the external walls, party walls between flats, floor slabs and stairs are made of CLT (Figure 4.2.3). The facades are externally insulated and brick-clad, and the interior walls and ceiling are encapsulated in plasterboard (Figures 4.2.4 to 4.2.6).

Figure 4.2.2. The building weight and foundations depth were limited by the Crossrail tunnel that crosses the plot underground. The lightweight structure allowed to deliver 42% more units (Waugh Thistleton Architects, 2014).

45

Figure 4.2.3. The honeycomb structure in CLT comprises floor slabs, internal walls, stairs and external walls (Shearing, 2017).

46

Figure 4.2.4 (left). Dalston Works section: the timber structure is concealed internal and externally Figure 4.2.5 (right above). Flat in Dalston Works: the timber structure is concealed internal and externally Figure 4.2.6 (right below). Dalston Works envelope: external materials palette Source: Waugh Thistleton Architects, 2014.

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The plot is in the junction of Dalston Lane and Martel Place. The surrounding buildings are four or five stories high, and up to eight stories in the west portion of the block (Figure 4.2.7).

Dalston Works is a stepped volume which tallest part is built against the vertical neighbours, reaching 10 storeys. The lowest volume follows Dalston Lane street elevation. Most flats have dual aspect, looking both outwards and to a courtyard.

All units have a balcony connected to the combined living room / kitchen.

Place

Dalst on La

ne

Martel

According to the energy strategy report by the sustainability consultants, Dalston Works’ regulated energy loads were calculated 1.9% below the target defined by the Building Regulations Part L, considering the architecture design and fabric energy efficiency. By adopting a centralized combined heat pump, air source heat pumps and photovoltaic panels improved this number dropped to 51% lower than Part L compliance. Considering the energy sources, it corresponds to a baseline of 210 tCO2 per annum, that was improved to 121 tCO2 per annum, in a 14,500m² GIA.

Figure 4.2.7. Dalston Works: site location and typical plan - 3rd floor (Waugh Thistleton Architects, 2014).

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4.3. Selection of units The selected units are on the third floor and were named according to the living room / kitchen orientation: the north flat’s living room/kitchen faces north, whereas its bedrooms face south, looking at the courtyard; the east flat’s living room / kitchen faces east, and its bedrooms face west, looking at the courtyard, and so on.

The flats are similar in floor area (60m2), except for the south unit (88m2) (Figures 4.3.1 to 4.3.4). In all units the floor-to-ceiling height is 2.55m and the floor-to-floor height is 3.00m.

N

3

2

S

1

1. Living room/kitchen 2. Single bedroom 3. Double bedroom 4. Double deroom 2

4 2

E

W

1

3

Figure 4.3.1 (left). North flat - floor plan Figure 4.3.2.(right). South flat - floor plan Source: Waugh Thistleton Architects, 2014.

3 1 2

2 3

1

Figure 4.3.3 (left). West flat - floor plan Figure 4.3.4.(right). East flat - floor plan Source: Waugh Thistleton Architects, 2014.

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a. b. c. d.

e. f. g. h. i. j. k. l. m.

50

wood flooring cement screed footfalll insulation CLT / cross-laminated timber/ mass timber ceiling void fibre insulation plasterboard rigid insulation brick air cavity reinforced concrete cement block cement render

4.4. Construction scenarios Scenario A is the base case and corresponds to the existing building. The construction materials and thicknesses were obtained from the architect’s technical drawings in the planning permission available from the Hackney Council planning website. Despite the external brickwork, the CLT wall core and slabs have low thermal mass compared to typical masonry constructions in concrete structure buildings. The CLT slab is concealed by an insulated false ceiling and the CLT walls are encapsulated with plasterboards (Figure 4.4.1).

concrete block wall core instead of mass timber. The internal finishes are in plasterboard. The insulation thicknesses were adapted to preserve the same U-values as the base case (Figure 4.4.2)

The hypothetical construction scenarios B, C, D and E vary in terms of embodied carbon and thermal mass, but U-values are constant.

Scenarios C and D are variations of A and B, as they repeat those constructions, but eliminate the false ceiling to increase the exposed thermal mass.

The ceiling is the most unobstructed surface in a room, providing a good opportunity to radiant heat storage. This is a strategy to improve the thermal comfort during warm periods. The insulation thickness in the floor construction was increased to compensate the elimination of insulation in the ceiling void (Figures 4.4.3 and 4.4.4).

Scenario B simulates the use of concrete slabs and a

In scenario E, the wall constructions were adapted

a b c d

e f g FLOOR/CEILING

g

g

g

i

d

d

d

j

h

h

INTERNAL PARTY WALL

INTERNAL WALL

EXTERNAL WALL / ENVELOPE

Figure 4.4.1. Base case (scenario A): cross-laminated timber constructions. Details developed according to Waugh Thistleton Architects’ drawings available from the Hackney Council Planning website.

51

a b c k

e f g

FLOOR/CEILING

g

g

g

l

l

i

h

i

h

INTERNAL PARTY WALL INTERNAL WALL EXTERNAL WALL / ENVELOPE Figure 4.4.2. Scenario B: reinforced concrete structure and masonry walls. a b c d FLOOR/CEILING

g

g

g

i

d

d

d

j

h

h

INTERNAL PARTY WALL

INTERNAL WALL

EXTERNAL WALL / ENVELOPE

Figure 4.4.3. Scenario C: cross-laminated timber constructions; exposed CLT slab.

52

to increase the exposed thermal mass. This is the highest thermal mass scenario explored, as opposed to the lightest construction analysed in the base case (Figure 4.4.5).

Because of the fire safety constraints explored in section 2, this research does not simulate the exposed CLT walls and ceiling.

a b c k FLOOR/CEILING

g

g

g

l

l

i

h

i

h

INTERNAL PARTY WALL INTERNAL WALL EXTERNAL WALL / ENVELOPE Figure 4.4.4. Scenario D: reinforced concrete structure and masonry walls; exposed concrete slab. a b c k FLOOR/CEILING

m l

m

m

l

i

h

i

h

INTERNAL PARTY WALL

INTERNAL WALL

EXTERNAL WALL / ENVELOPE

Figure 4.4.5. Scenario E: reinforced concrete structure and masonry walls; maximised exposed thermal mass.

53

4.5. Operation scenarios Three building operation modes were simulated to verify the required annual heating and cooling loads under different thermal comfort conditions.

The free running mode was simulated to analyse the building’s passive response to the climate, explore its potential to provide adaptive thermal comfort, and identify the critical periods in which either heating or cooling is needed.

The subsequent simulations introduce the mechanical systems for heating and cooling, according to different set points depending on the target temperatures for comfort.

The mixed mode combines heating and cooling with a dead band in between, when thermal comfort is passively achieved and the occupants practice adaptive strategies, such as natural ventilation. The aim of environmental design is to maximise the dead band and avoid unnecessary energy demand considering the climate context.

The mechanical mode is the most energy-intensive operation scenario, as it introduces heating and cooling, and mechanical ventilation. The systems are controlled by a thermostat that sets fixed air temperatures and the mechanical ventilation system provides fresh air permanently.

temperature changes steadily according to variations in the external environment and the radiant heat exchange should be limited to avoid radiant temperature asymmetry, an imbalance in the surrounding surfaces temperatures as this may cause discomfort in both cold and warm conditions (CIBSE, 2015). The operative temperature is a more comprehensive measure to assess thermal comfort, as it combines the air (DBT) and surface temperatures (MRT). International standards as the American ASHRAE-55 and the British standard BS EN 15251 refer to resultant or operative temperature.

The frequency of operative temperature within adaptive comfort limits may vary depending on the adopted comfort band. This study adopted CIBSE Guide A recommendation and the British standard BS EN 15251:2007 adaptive comfort band, based on the occupants’ adaptability according to fluctuations in the running mean temperature (Equations 4.5.1.1 and 4.5.1.2).

Comfort temperature (Θcom ) for free-running operation (CIBSE, 2015): (a) upper margin: Θcom = 0.33 Θrm + 20.8

(Equation 4.5.1.1)

(b) lower margin:

4.5.1. Free-running mode, adaptive Θcom = 0.33 Θrm + 16.8 (Equation 4.5.1.2) thermal comfort and overheating The flats’ temperature profiles of a cold and warm In passively controlled buildings, the occupants respond actively to the environment to avoid thermal stress. It includes actions to change the comfort of individuals, such as changing the body insulation level (clothes), the activity, or the position, as well as initiatives that change the indoor temperature, such as controlling operable shading and openings’ aperture. Those are adaptive thermal comfort measures (Nicol et al., 2012).

In successful free-running buildings the indoor

54

week (January 1st to 7th and July 21st to 27th) in the free running mode was analysed to verify the influence of the radiant component in the operative temperature, considering the building fabric’s properties and the rooms exposure to solar gains, depending on their orientation.

According to the weather data used in the analysis, during this cold week in January the external temperature varies between 4 and 12ºC, with the running mean fluctuating between 1.9 and 5.4ºC.

In summer, the external temperature ranges from 15 to 31ºC, and the running mean temperature from 18.3 to 21.1ºC.

4.5.2. Mixed mode

static comfortable temperature in mechanically controlled and hybrid buildings, but a comfort band which upper and lower margins vary according to fluctuations in the running mean temperature (Equations 4.5.2.1 to 4.5.2.3).

Buildings operating in mixed mode rely on passive strategies to achieve thermal comfort in a freerunning mode but are also provided with heating and cooling systems. In hybrid mode, the indoor climate is controlled by a thermostat set to provide heating, cooling and a dead band in between. The latter is the range of temperatures in which the building operates in the free-running mode, using internal and external heat gains to cope with low temperatures, and natural ventilation as a passive cooling strategy.

Running mean temperature

The mixed mode provides the occupant with control of passive strategies to improve the thermal conditions when the temperature is mild, but still offers a heating and cooling if needed. This operation mode gives the opportunity to adapt to a wider range of temperatures in free-running mode, which results in a lower energy demand. An increase by 1K in the range of acceptable temperatures may result in important energy savings (Nicol et al., 2012).

Θcom = 0.09 Θrm + 20.6

In this analytic study the set point is 20°C for heating and 26°C for cooling. When the indoor dry bulb temperature is between those values, the assumption for natural ventilation is that the aperture will begin to open if the indoor dry bulb temperature exceeds 21°C. It will be fully open if the temperature reaches 23°C. If the external temperature exceeds the indoor temperature, the windows should be closed to not bring hot air in.

If the indoor DBT reaches 26°C, the mechanical system replaces the natural ventilation as a cooling measure.

CIBSE Guide A (2015) does not recommend a

Θrm= (Tod–1 + 0.8 Tod–2 + 0.6 Tod–3 + 0.5 Tod–4 + 0.4 Tod–5 + 0.3 Tod–6 + 0.2 Tod–7) / 3.8 (Equation 4.5.2.1) Comfort temperature (Θcom ) for heated or cooled operation (CIBSE, 2015): (a) upper margin: Θcom = 0.09 Θrm + 24.6

(Equation 4.5.2.2)

(b) lower margin: (Equation 4.5.2.3)

4.5.3. Mechanical mode Buildings operating in mechanical mode rely on active systems to provide permanent ventilation, and heating or cooling according to the indoor air temperature measured by the thermostat.

The energy loads to provide comfortable conditions in this mode is strongly affected by the building’s orientation and other design variables, including the constructions’ properties.

The intention of this simulation is to calculate the loads to keep the indoor temperatures within a stricter temperature band, that does not rely on the occupants’ adaptability.

In this analytic study the set point is 20°C for heating and 24°C for cooling during occupancy hours. A mechanical ventilation system provides fresh air permanently and according to the number of occupants and rooms’ air volume. There is no natural ventilation.

55

4.6. Hypothesis for simulations Heavyweight constructions provide more thermal stability than lightweight, as the heat flow is slower through high thermal mass materials. In a free running mode, it is expected, therefore, that lightweight constructions register higher operative temperatures during summertime and lower temperatures in winter than in heavyweight buildings.

The buildings’ constructions not only influence the environment in the free running mode, but also have an impact on the energy required to operate mechanical systems satisfactorily.

Considering the above concepts, the free running mode simulations are expected to show that heavyweight construction scenarios offer more stable operative temperatures, a higher frequency of thermal comfort hours, and no overheating. The fabrics efficient thermal response should result in lower heating and cooling annual loads when the mixed or mechanical mode are simulated.

56

As mass timber buildings are lightweight, it is expected that the fluctuation in indoor temperatures has a high correlation with the external environment, which increases the energy loads for heating and cooling.

The orientation is also a major factor of influence in the rooms’ thermal conditions. The solar gains in different aspects may vary considerably. Southfacing rooms are exposed to higher levels of solar radiation, requiring lower heating but greater annual cooling loads and risk of overheating than units in other building aspects.

The analysis of materials’ properties and application of environmental principles allow to predict the behaviour of different constructions. This analytic study provided the magnitude of the difference between the thermal comfort and energy loads in existing and hypothetical building envelope constructions.

4.7. Analysis overview: the influence of orientation The annual heat gains are similar in the north, west and east units: solar gains are approximately 40kWh/m² and internal gains, 80kWh/m². In the south flat, the annual solar gains are 55kWh/m² and internal gains, 86kWh/m². The mechanical mode simulations show that annual loads for space conditioning are also higher in the south unit and lower in the other flats, regardless of the construction scenario (Figure 4.7.1 to 4.7.5). This pattern in the building response indicates that solar gains are a driving factor for the heating and cooling needs in the analysed building. The annual loads breakdown into heating and cooling confirms the influence of orientation, as the south flat annual demand for cooling is markedly higher (Figures 4.7.6 to 4.7.9).

accounts for the most intense solar gains.

Bedrooms in the North flat have the highest occurrence of operative temperature above 26°C, followed by the East flat bedrooms. It is explained by the orientation of these rooms to south and west, that receive the largest amount of solar radiation.

Despite the highest equipment heat gains, living room / kitchens in this building suffer less from overheating than bedrooms in the north, west and east flats. Although heat gains are intense in the occupancy hours, with high peak loads, the intermittent occupancy hours allow heat losses during night-time. Those rooms are also less compact than the bedrooms, which possibly affects the time to heat their air volume, so the overheating occurrence is reduced.

The south flat presented the highest percentage of overheating hours, followed by the north flat. The exposure of the living room/kitchen (south flat) and the bedrooms (northAnnual flat) to the southaccording aspect loads to flat orientation 90

kWh/m2

80 70

60 50 40 30

North

South

West

East

solar gains

internal gains

annual loads - base case

annual loads - scenario B

annual loads - scenario C

annual loads - scenario D

annual loads - scenario E Figure 4.7.1. Annual loads according to flat orientation.

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Annual heat/cooling loads per m2 GIA

Annual heat/cooling loads per m2 GIA

North Flat - mechanical mode

South Flat - mechanical mode

70

50

-1.3

-1.2

-1.7

40 30

60

-1.5

-2.9

C

D

E

30 20

10

10 0

B

C

D

B

E

annual heating + cooling loads annual heating loads annual cooling loads base case - annual heating loads base case - annual cooling loads base case - annual heating + cooling loads

annual heating + cooling loads annual heating loads annual cooling loads base case - annual heating loads base case - annual cooling loads base case - annual heating + cooling loads

Figure 4.7.2.

Figure 4.7.3.

Annual heat/cooling loads per m2 GIA

Annual heat/cooling loads per m2 GIA

West Flat - mechanical mode

East Flat - mechanical mode

70

70 60

-1.2

50

-1.2

-1.6

56.7 -1.7

kWh/m2

kWh/m2

-2.7

40

20

0

56.8

-1.7

50

-1.6

kWh/m2

kWh/m2

55.5

66.9

60

70

40 30

60 50

-1.4

-1.7

-2.0

-2.2

C

D

E

40 30

20

20

10

10 0

0

B

C

D

E

B

annual heating + cooling loads annual heating loads annual cooling loads base case - annual heating loads base case - annual cooling loads base case - annual heating + cooling loads

Figure 4.7.4.

58

annual heating + cooling loads annual heating loads annual cooling loads base case - annual heating loads base case - annual cooling loads base case - annual heating + cooling loads

Figure 4.7.5.

Annual heat/cooling loads per m2 GIA

Annual heat/cooling loads per m2 GIA

North Flat - mechanical mode

South Flat - mechanical mode

0

C

annual heating loads base case - annual heating loads

D

B

E

annual cooling loads base case - annual cooling loads

Figure 4.7.6.

-0.6

-2.3

-2.0

D

E

annual cooling loads base case - annual cooling loads

Figure 4.7.7.

Annual heat/cooling loads per m2 GIA

West Flat - mechanical mode

East Flat - mechanical mode

40

10

-1.6

-0.6

-1.3

-0.7

-0.4

-1.3

-0.8

30 20

kWh/m2

-0.3

27.6 -1.4

-0.4

-1.2

-0.9

-0.3

-0.4

29.2

-0.8

30 27.1

-0.5

40

kWh/m2

C

annual heating loads base case - annual heating loads

Annual heat/cooling loads per m2 GIA

20

-0.5

10 0

B

29.8

-0.7

-0.5

-0.1

-1.5

-0.4

-1.3

-0.3

-0.9

10

30 20

kWh/m2

kWh/m2

20

-0.9

29.8

-1.2

30 27.3

-0.5

28.2

37.1

40

-1.0

40

10 0

0

B

C

annual heating loads base case - annual heating loads

Figure 4.7.8.

D

E

annual cooling loads base case - annual cooling loads

B

C

annual heating loads base case - annual heating loads

D

E

annual cooling loads base case - annual cooling loads

Figure 4.7.9.

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4.8. Detailed analysis: the influence of construction in thermal comfort and annual loads 4.8.1. Base case / Scenario A: the existing adaptive comfort conditions, whereas in the living room / kitchens, it drops below comfortable values building during a significant number of occupancy hours.

FREE RUNNING Annual and summer frequency of overheating In the free running dynamic thermal simulation, the frequency of operative temperatures above 26ºC during occupancy hours exceeds the 3% threshold (CIBSE, 2015) in all the flats, except for the north flat’s living room / kitchen.

Although CIBSE TM52 and ASHRAE criteria for adaptive comfort do not consider a fixed temperature and admit higher values, CIBSE TM59 (2017), recommends that bedrooms do not exceed 26ºC during night-time for more than 1% of annual hours. Only one bedroom fails this criterion (East flat - Double bedroom, facing west).

The seasonal operative temperature profile demonstrates that all the assessed rooms experience multiple occurrences of temperatures exceeding the maximum recommended by CIBSE TM52 (2013) during at least three weeks in summer.

All flats partly fail the adaptive overheating assessment according to CIBSE TM52 criteria: only 5 out of 13 analysed rooms passed it. Although they comply with criterion 1 (number of hours exceeding the comfort range during the occupied hours over the summer period), all rooms fail in the daily limit of severity of the overheating (criterion 2) and most exceed the absolute maximum daily temperature (criterion 3). (see Appendix tables 4.8.1) Cold week temperature profile During the analysed cold week, the operative temperatures in the bedrooms fluctuate within

60

The south living room / kitchen’s frequency within BS EN 15251 adaptive comfort band is 82%, but in the north and east units it is lower than 50% of occupancy hours.

The difference between DBT and MRT in bedrooms oscillates between 0 and 1.9K. The lowest values are recorded during night-time, when solar and internal gains are null or very low (Figures 4.8.1.1 and 4.8.1.2).

Warm week temperature profile

The dry bulb and mean radiant temperatures fluctuate according to a similar pattern (Figures 4.8.1.3 and 4.8.1.4) . When the external temperature is equal or above 24ºC, there is a stronger correlation between the dry bulb and the mean radiant temperature: the difference between them is smaller than 2K, remaining close to 1K most of the time. When the external temperature is lower than 24ºC this difference rises up to 3K, indicating that the operative temperature in these rooms remains more stable in cooler weather conditions. This is critical in the South flat’s living room / kitchen, where the difference between MRT and DBT exceeds 3K for 16 hours during the assessed week, reaching 4.3K on July 25th, at 2pm (Figure 4.8.1.5).

Differences of 3K or higher indicate asymmetrical thermal radiation, an evidence of probable thermal discomfort. This is usually attributed to large glazing areas, but opaque constructions may also provide high radiant heat transfer.

The capacitive insulation property of the lightweight timber construction is limited, and so is its potential to store heat from solar gains and release during cooler hours. However, the mass timber and

Cold week temperature profile Free running mode - Scenario A North flat - Single Bedroom

temperature (⁰C)

23

18

13

8

Cold week temperature profile

ture profile

Scenario A m / kitchen

Free running mode - Scenario A Cold room week/ kitchen temperature profile South flat - Living 02-Jantemperature 03-Jan 04-JanFree running05-Jan 07-Jan mode - Scenario06-Jan A Cold week profile South flat - Base Livingcase room / kitchen A – North flat - single bedroom.

Figure 4.8.1.1.Free Coldrunning week temperature profile mode. / Scenario mode - Scenario A – free-running BS EN South 15251 adaptive comfort External temperature DBT MRT OT flat - Living roomband / kitchen 3 01-Jan

23

18

temperature (⁰C)

temperature (⁰C)

23

13

8

18

13

8 3 01-Jan

05-Jan

02-Jan 03-Jan 04-Jan 05-Jan 06-Jan 07-Jan 3 Figure 4.8.1.2.

Cold week07-Jan temperature mode.

Base case / Scenario flat – Living room/ 01-Jan 02-Jan profile – free-running 03-Jan 04-Jan 05-Jan A – South06-Jan 07-Jan 06-Jan BS EN 15251 adaptive comfort band External temperature DBT MRT OT kitchen.

03-Jan 04-Jan 05-Jan 06-Jan 07-Jan 07-Jan BS EN 15251 adaptive External temperature DBT MRT DBT MRT OTcomfort band

02-Jan 06-Jan perature 07-Jan 251 DBT adaptive comfort band MRT MRT

External temperature OT

DBT

MRT

OT

OT

61

OT

Warm week temperature profile Free running mode - Scenario A North flat - Single Bedroom

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-JulWarm week 24-Jul temperature25-Jul profile

26-Jul

27-Jul

Free running modemode.

- Scenario Figure 4.8.1.3. Warm week temperature profile – free-running BaseAcase / Scenario A – North flat - single bedroom.

temperature (⁰C)

35 30

BS EN 15251 adaptive comfort band

West flat -temperature Single bedroom External

MRT

OT

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

DBT

TM59 - overheating threshold

25 20 15 21-Jul

22-Jul

temperature25-Jul profile 23-JulWarm week 24-Jul

26-Jul

27-Jul

temperature temperature (⁰C) (⁰C)

Free running mode - Scenario A Figure 4.8.1.4. Warm week temperature profile – week free-running mode.

Base case / Scenario A – West flat – Single bedroom.

Warm temperature profile South flat - Living room / kitchen DBT Free External runningtemperature mode - Scenario A 35 BS EN 15251 adaptive comfort band SouthOT flat - Living room / kitchen MRT TM59 - overheating threshold 35 30

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

30 25

25 20

20 15 21-Jul 22-Jul 23-Jul 24-Jul 25-Jul 26-Jul 27-Jul 15 Figure 4.8.1.5. Warm week temperature profile – free-running mode. Base case / Scenario A – South flat – Living room/ 21-Jul 22-Jul 23-Jul 24-Jul 25-Jul 26-Jul 27-Jul kitchen.

BS EN 15251 adaptive comfort band External temperature DBT MRT BS EN 15251 adaptive comfort band CIBSE TM52 - Tmax MRT

OT External temperature CIBSE TM52 - Tupp OT

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

62

TM59 - overheating threshold DBT TM59 - overheating threshold

insulation layers’ resistivity prevent heat losses and keeps the operative temperature above 23ºC despite the external temperature drop to 17ºC. The operative temperature in the modelled rooms may exceed the threshold of 26ºC even when the external temperature is as low as 20ºC. However, considering adaptive thermal comfort criteria, the maximum comfort temperature varies according to the running mean temperature and temperatures above 26ºC may be tolerated.

In the assessed week the comfort limit goes beyond this absolute threshold, reaching 27.8 to 28.8ºC. Despite the acceptable high values, all bedrooms may experience overheating for at least 4 days in this period (see graphs for all rooms in the Appendix images, section 4.8.1).

On July 21st, when the external temperature peaks at 31ºC, the simulations register a 14-hour long period of overheating, when the operative temperatures exceed CIBSE TM52 absolute upper limit and get close to 34ºC. In a milder day of this week (July 23rd), when the external temperature ranges from 20 to 25ºC, overheating is still registered for at least 5 hours in all bedrooms, except for the only room that is shaded by the overhang of a balcony (South flat Double bedroom 2).

In north-facing rooms, the diffuse radiation is notably more representative than the direct, therefore, the solar gains are significantly lower than in the other façades. The temperature profiles indicate that the radiant component is as important in these rooms as in the south aspect, and the milder temperatures are attributed to lower solar gains.

MIXED MODE Annual heating and cooling loads Considering the dead band between 20 to 26ºC, the annual heating loads are slightly greater than 3kWh/m² for the north, west and east flats, whereas the south unit demands only 2.5kWh/m².

The annual cooling loads in the south flat are the

highest, 3.6kWh/m², whereas the west flat requires only 2.4kWh/m².

Despite the minor difference described above, the magnitude of annual loads for thermal control is roughly 6kWh/m² for all flats. Since the mechanical systems are activated by a thermostat, during the free running mode period the dry bulb temperature remains within the set points for heating and cooling. However, the operative temperature is influenced by the radiant component and the occupants may experience discomfort despite the registered DBT. Thermal comfort conditions - frequency of OT The frequency of operative temperatures greater than or equal to 26ºC is above CIBSE Guide A’s recommendation of a maximum 3% of occupancy hours in all flats. Although it is a south-facing room, the shaded south flat bedroom is the only zone with acceptable frequency of operative temperatures above the 26ºC threshold.

Nonetheless, the maximum temperature for adaptive comfort is exceeded solely in the south flat’s living room / kitchen, for 6 hours during occupancy throughout the assessed summer week.

MECHANICAL MODE Annual heating and cooling loads The fully mechanical mode ensures a comfortable range of operative temperatures to all rooms in the assessed units, throughout the entire year.

However, the occurrence of OT above 26ºC is not negligible, despite the energy loads for cooling.

The annual heating loads in the north and east units, are approximately 27.5kWh/m², while the south and west flats require 29.8kWh/m². Regarding cooling, the south flat’s loads are 37.1kWh/m², roughly 30% above the other units, where cooling and heating loads have similar values.

The overall annual loads in the analysed flats range from 55.5kWh/m² (north unit) to 66kWh/m² (south unit).

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4.8.2. Scenario B

comfort upper limit for 5 hours during summer.

FREE RUNNING

In the west flat, the number of overheating hours in summer decreased by half and all rooms comply with CIBSE TM52 overheating assessment criteria.

Annual and summer frequency of overheating There is a very small reduction in the frequency of operative temperatures above 26ยบC, compared to scenario A, such as a decrease from 6% to 4.5% of occupancy hours. The only rooms in which this value drops below the limit of 3% of occupancy hours are the north and west living room / kitchens.

The east flat recorded a reduction of roughly 45% in the number of overheating hours in summer. Its west-facing bedrooms still experience overheating in summer, despite the improvement in hours exceeding the absolute limit.

Considering CIBSE TM52 adaptive overheating criteria for scenario A, 8 among the 13 analysed rooms failed in at least 2 criteria. The increase in thermal mass in scenario B had impacting improvements in only 3 rooms but caused an important drop in the number of hours exceeding the comfort range and absolute limit in all flats.

During the cold week of January, the difference between the base case and scenario B operative temperatures is negligible too. It rarely reaches 0.5K and is insufficient to provide a significant increase in hours within the adaptive comfort band. (Figures 2.8.2.1 and 2.8.2.2).

The occurrence of temperatures above 26ยบC in bedrooms during night-time was already acceptable in scenario A, but there was a slight reduction in this number, improving the comfort frequency in all bedrooms. In this scenario, all double bedrooms have acceptable comfortable conditions, except for the west-facing double bedroom in the east flat. Nonetheless, there is only one single bedroom passing CIBSE TM52 overheating assessment: the east-facing single bedroom in the west flat.

Concerning the living room / kitchens, there was an important thermal improvement in the west unit, whereas the south flat still records overheating in this scenario.

In the north unit, the number of overheating hours in summer was reduced by half in all rooms. The only bedroom that exceeded the limit of night hours above 26ยบC had a small reduction in nighttime overheating, enough to make it comply with CIBSE TM59 criterion 2.

In the south flat, the overheating hours in summer were reduced by at least 20%, and up to 35%.

However, the changes in constructions were not sufficient to cope with overheating in the southfacing living room / kitchen, where the operative temperature still exceeds CIBSE TM52 absolute 64

Cold week temperature profile

Warm week temperature profile During the warm week of 21st to 27th July, the MRT in construction scenario B oscillates slightly less than in the base case (Figures 2.8.2.3 to 2.8.2.5).

In most rooms the change in construction reduced the OT by more than 1K at the hottest hour of the week, when the external temperature reaches 25oC to 31 oC. If the external temperature is milder, construction B contributes to decreasing the internal temperature by less than 0.5K. Nonetheless, the reduction is insufficient to avoid overheating and provide a relevant number of additional hours within comfort.

The temperatures drop more significantly in single bedrooms, which are more compact than double bedrooms. In the only shaded room, south facing double bedroom, there is a smaller amplitude of MRT, making the OT more stable as well.

Nonetheless, the absolute difference in the OT values is negligible.

MIXED MODE Annual heating and cooling loads The annual loads for space conditioning are 15% lower than in the base case, and the reduction in

Cold week temperature profile Free running mode - Scenario B North flat - Single Bedroom

temperature (⁰C)

23

18

13

8

Cold week temperature profile

ture profile

Scenario A m / kitchen

Free running mode - Scenario B Cold room week/ kitchen temperature profile South flat - Living 02-Jantemperature 03-Jan 04-JanFree running05-Jan 07-Jan mode - Scenario06-Jan A Cold week profile South flat - Scenario Living room kitchenflat - single bedroom.

Figure 4.8.2.1.Free Coldrunning week temperature profile mode.

B –/North mode - Scenario A – free-running BS EN South 15251 adaptive comfort External temperature DBT MRT flat - Living roomband / kitchen 3 01-Jan

OT

23

18

temperature (⁰C)

temperature (⁰C)

23

13

8

18

13

8 3 01-Jan

05-Jan

02-Jan 03-Jan 04-Jan 05-Jan 06-Jan 07-Jan 3 Figure 4.8.2.2.

Cold week 07-Jan temperature mode.04-Jan Scenario B – South flat – Living room/kitchen.

01-Jan 02-Janprofile – free-running 03-Jan 05-Jan 06-Jan 07-Jan 06-Jan BS EN 15251 adaptive comfort band External temperature DBT MRT OT 03-Jan 04-Jan 05-Jan 06-Jan 07-Jan 07-Jan BS EN 15251 adaptive External temperature DBT MRT DBT MRT OTcomfort band

02-Jan 06-Jan perature 07-Jan 251 DBT adaptive comfort band MRT MRT

External temperature OT

DBT

MRT

OT

OT

65

OT

Warm week temperature profile Free running mode - Scenario B North flat - Single Bedroom

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-JulWarm week 24-Jul temperature25-Jul profile

26-Jul

27-Jul

Free running modemode.

- Scenario B Figure 4.8.2.3. Warm week temperature profile – free-running Scenario B – North flat - single bedroom.

temperature (⁰C)

35 30

West flat -temperature Single bedroom External

BS EN 15251 adaptive comfort band MRT

OT

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

DBT

TM59 - overheating threshold

25 20 15 21-Jul

22-Jul

Warm week temperature25-Jul profile 24-Jul

23-Jul

26-Jul

27-Jul

26-Jul

27-Jul

temperature temperature (⁰C) (⁰C)

Free running mode - Scenario B Figure 4.8.2.4. Warm week temperature profile – week free-running mode.

Scenario South flat - Living room / kitchen Warm temperature profile B – West flat – Single bedroom.

35 BS EN 15251 adaptive comfort band DBT Free External runningtemperature mode - Scenario A SouthOT flat - Living room / kitchen MRT TM59 - overheating threshold 35 30

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

30 25

25 20 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

15 Figure 4.8.2.5. Warm week temperature profile – free-running mode. Scenario B – South flat – Living room/kitchen.

21-Jul 22-Jul 23-Jul 24-Jul 25-Jul 26-Jul 27-Jul BS EN 15251 adaptive comfort band External temperature DBT

MRT BS EN TM52 15251-adaptive CIBSE Tmax comfort band

OT External temperature CIBSE TM52 - Tupp

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

MRT

66

OT

TM59 - overheating threshold DBT TM59 - overheating threshold

cooling loads represents more than two thirds of this improvement. However, the absolute difference is not significant, as the absolute values for both scenarios are quite low.

Thermal comfort conditions - frequency of OT The frequency of OT above the absolute threshold of 26oC dropped by third or even half in some cases, but it is still above 3% for all rooms except for the shaded south bedroom and the west flat living room.

MECHANICAL MODE Annual heating and cooling loads The mechanical mode loads decreased by 2%.

Despite the full mechanical control, the south living room/kitchen still records operative temperatures above 26 oC during 10% of the occupancy hours.

Warm week temperature profile The exposed concrete slab (scenario D) contributes to reduce the amplitude in indoor temperatures. It improves the thermal comfort during the hottest hours, when the OT in all rooms is roughly 2K below the temperatures simulated for the base case.

When the external temperature is below 23oC the indoor temperatures in scenarios A, B, C and D are quite similar, varying by few decimals.

The response of construction C is equivalent to the base case. In the hottest periods of the year, exposing the CLT slab was not effective to improve the thermal comfort.

In scenario D there was an improvement in the frequency within the adaptive comfort band by 10 to 20% above the base case frequency. The only room that had a very small increase in thermal comfort hours is the South flat living room/kitchen, which receives the most intense solar radiation.

4.8.3 Scenarios C and D – exposed thermal Cold week temperature profile In the cold season the exposed slabs do not provide mass: ceiling FREE RUNNING Annual and summer frequency of overheating Eliminating the plasterboard ceiling from the base case (scenario C) had markedly less impact than adding thermal mass to the constructions’ core (scenario B and D).

There is no significant difference between the base case and the exposed CLT slab (scenario C), whereas there was an improvement in thermal comfort in scenario D. Even so, the frequency of OT above 26oC remains above 3% of occupancy hours in most rooms with exposed concrete ceiling. The only rooms with OT frequency below this threshold are the double bedrooms in the South flat and the East living room/kitchen, and the living room/kitchen in the North and West flats, that were already below this threshold in the base case scenario.

significant improvements in thermal comfort. The OT for scenarios A, B, C and D is almost the same.

Besides negligible differences in the absolute values, the frequency within adaptive comfort is roughly the same for all construction scenarios.

MIXED MODE Annual heating and cooling loads The annual loads for the mixed mode decreased slightly in scenario C, but more expressively in scenario D, due to a reduction in cooling loads. The absolute difference is negligible, though.

Thermal comfort conditions - frequency of OT The frequency of OT above 26oC in scenario C is higher than in B, despite the slight reduction compared with the base case. In scenario D almost all rooms recorded less than 3% of occupancy hours above 26oC.

67

This improvement indicates that the thermal mass contributes not only to maximising the dead band, but also provides effective thermal comfort when the cooling system is on.

MECHANICAL MODE Annual heating and cooling loads In the mechanical mode, scenarios B, C and D annual loads are roughly the same. The frequency of OT>26oC in the South flat living room/kitchen had a marked reduction, from 10% in the base case to 3.8% of the occupancy hours.

The operative temperatures remain more stable despite the fluctuation in external temperatures.

There is a longer time lag between the exposure to radiation and the heat transfer through the construction. The heat flow through the fabric occurs at a slower pace and the ceiling and walls behave as a heat sink because of the exposed thermal mass.

Warm week temperature profile The frequency within adaptive comfort increased significantly compared to the base case, despite the insignificant difference from scenario D. Cold week temperature profile

4.8.4 Scenario E - exposed thermal mass: ceiling and walls

In the cold season the temperature profile was barely affected by the changes in construction.

Despite a four-fold increase in the surface area MIXED MODE AND MECHANICAL MODE of exposed thermal mass, this scenario does not The addition of exposed thermal mass in the walls provide relevant improvements compared to was not effective to improve the annual loads nor scenario D, where the only exposed is the the OTprofile Coldsurface week temperature simulated in scenario D, where the exposed concrete slab.

Free running mode - Operative temperature thermal mass surface is limited to the ceiling.

North flat - Single Bedroom

temperature (⁰C)

25 20

15 10 5 01-Jan

02-Jan

03-Jan

04-Jan

05-Jan

Cold week temperature profile

06-Jan

07-Jan

running mode - Operative temperature Figure 4.8.4.1. Cold week temperature Free profile – free-running mode. Base case and all hypothetical scenarios – North flat BS EN 15251 adaptive comfort band External OT - scenario A South flat -temperature Living room/kitchen - single bedroom.

25 OT - scenario E

OT - scenario B

OT - scenario C

temperature (⁰C)

OT - scenario D 20

15 10 5 01-Jan

02-Jan

03-Jan

04-Jan

05-Jan

06-Jan

07-Jan

Figure 4.8.4.2. Cold week temperature profile – free-running mode. Base case and all hypothetical scenarios – South flat – Living room/kitchen.

BS EN 15251 adaptive comfort band External temperature OT - scenario A OT - scenario E OT - scenario D

68

OT - scenario B

OT - scenario C

Warm week temperature profile

Free running mode - Operative temperature North flat - Single Bedroom

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

Warm week24-Jul temperature profile 23-Jul 25-Jul

26-Jul

27-Jul

Figure 4.8.4.3. Warm week temperature profile – free-running mode.

Base case and all hypothetical scenarios – North flat Free running mode - Operative temperature - single bedroom.

West flat - Single Bedroom

temperature (⁰C)

35 30

BS EN 15251 adaptive comfort band OT - scenario E CIBSE TM52 - Tupp OT - scenario D

External temperature TM59 - overheating threshold OT - scenario B

OT - scenario A CIBSE TM52 - Tmax OT - scenario C

25 20 15 21-Jul

22-Jul

Warm week24-Jul temperature profile 23-Jul 25-Jul

26-Jul

27-Jul

Warm temperature profile Figure 4.8.4.4. Warm week temperature profile –week free-running mode.

Base case and all hypothetical scenarios – West flat Free running mode - Operative temperature Free running mode - Operative temperature – Single bedroom.

South flat - Living room/kitchen

temperature temperature (⁰C) (⁰C)

35 35 30 30

BS EN 15251 adaptive comfort band OT - scenario E CIBSE TM52 - Tupp OT - scenario D

temperature SouthExternal flat - Living room/kitchen

TM59 - overheating threshold OT - scenario B

OT - scenario A CIBSE TM52 - Tmax OT - scenario C

25 25 20 20

15 1521-Jul 22-Jul 23-Jul 24-Jul 25-Jul 26-Jul 27-Jul 21-Jul 23-Jul 24-Jul 25-Julcase and all 26-Jul 27-Jul – South flat Figure 4.8.4.5. Warm22-Jul week temperature profile – free-running mode. Base hypothetical scenarios

– Living BSroom/kitchen.

EN 15251 adaptive comfort band BS 15251 adaptive comfort band OT EN - scenario E OT - scenario CIBSE TM52 - ETupp CIBSE TM52 - D Tupp OT - scenario OT - scenario D

External temperature External temperature TM59 - overheating threshold TM59 - overheating threshold OT - scenario B OT - scenario B

OT - scenario A OT - scenario CIBSE TM52 - A Tmax CIBSE TM52 - CTmax OT - scenario OT - scenario C

69

Frequency of OT >26℃ (%) Free running mode

Frequency of OT >26℃ (%) Free running mode

North flat

B

South flat

C

D

Single bedroom (%)

E

9%

9%

6%

6%

3%

3%

0%

0% B C D E Single bedroom (%) Double bedroom (%) Figure 4.8.4.7.

Frequency of operative CIBSE temperature above Living room/kitchen (%) Guide A overheating limit (%) Frequency (%) bedroom - base case (%) Single bedroom - base case (%) of OT >26℃ Double 26oC during occupancy hours – free-running mode.

Base case Living room/kitchen - base caserunning (%) Free mode Double bedroom 2 Double bedroom 2 - base case and all scenarios – South flat.(%)

Double bedroom (%)

FigureLiving 4.8.4.6.

Frequency of operative CIBSE temperature above room/kitchen (%) Guide A overheating limit 26oC (%) Frequency of OT >26℃Double (%) bedroom - base case (%) bedroom - base case (%) duringSingle occupancy hours – free-running mode. Base case and all Free mode Living room/kitchen - base caserunning (%) scenarios – North flat.

West flat Frequency of OT >26℃ (%) Free running mode South flat

B

C

D

9%

9%

6%

6%

9% 3%

3%

6% 0%

E

3%

bedroom (%) bedroom (%) Figure Single 4.8.4.8 Frequency of operative Double temperature above Living room/kitchen (%) CIBSE Guide A overheating limit 26oC (%) bedroom - base case (%) bedroom - base case (%) duringSingle occupancy hours – free-runningDouble mode.

Base case and all Living room/kitchen - base case (%) 0% scenarios – West flat.

B C Single bedroom (%) Living room/kitchen (%) Single bedroom - base case (%) Living room/kitchen - base case (%) Double bedroomloads 2 - base case (%) 2) & Annual (kWh/m

D

East flat

E Double bedroom (%) CIBSE Guide A overheating limit (%) Double bedroom - base case (%) Double bedroom 2

B

4

8.0%

2

4.0% 3.…

D

E

0.0%

loads (kWh/m2) Heating loads (kWh/m2) FigureCooling 4.8.4.10.

Annual heating and cooling loads + frequency Double bedroom 1 (%) Double 2(%) (%) Annual loads (kWh/m2above ) & Frequency of OTbedroom >26℃ of operative temperature 26oC during occupancy hours Living room/kitchen (%) Mixed mode CIBSE Guide A overheating limit (%) Single bedroomBase - base case (%)and all hypothetical Double bedroom - base case–(%) – mixed mode. case scenarios North West flat flat. Living room/kitchen - base case (%)

kWh/m2

6

kWh/m2

6

4

4

Annual loads (kWh/m2) & Frequency of OT >26℃ (%) Mixed mode South flat

2 0

B

C

D

E

8% 4% 3% 12.0% 0% 8.0%

70

Heating loads (kWh/m2) Double bedroom 2 (%) CIBSE Guide A overheating limit (%) Double bedroom - base case (%)

6

12.0%

4

8.0%

2

4.0% 3.…

0

B

C

D

0.0%

E

Cooling loads (kWh/m2) Heating loads (kWh/m2) Figure 4.8.4.11.

Annual heating and cooling loads + frequency Double bedroom 1 (%) Double (%) Annual loads (kWh/m2) &above Frequency of OTbedroom >26℃2(%) of operative temperature 26oC during occupancy Living room/kitchen (%) CIBSE Guide A overheating limit (%) Mixed mode hoursSingle – mixed mode.

Base case and all hypothetical scenarios bedroom - base case (%) Double bedroom - base case (%) East flat Living room/kitchen - base case (%) – South flat.

12%

loads (kWh/m2) Heating loads (kWh/m2) FigureCooling 4.8.4.12.

Annual heating and cooling loads + frequency Single bedroom (%) Double bedroom (%) 4.0% of2 operative temperature above 26oC during occupancy hours Living room/kitchen (%) CIBSE Guide A overheating limit 3.… (%) Single bedroomBase - base case (%) and all hypothetical Double bedroom - base case – (%)West – mixed mode. case scenarios 0 0.0% - base case (%) flat. Living room/kitchen B C D E Cooling loads (kWh/m2) Double bedroom 1 (%) Living room/kitchen (%) Single bedroom - base case (%) Living room/kitchen - base case (%)

kWh/m2

12.0%

kWh/m2

kWh/m2

South flat

6

C

0%

E

Annual loads (kWh/m2) & Frequency of OT >26℃ (%) Mixed mode

South flat

B

D

Single bedroom (%) bedroom (%) Figure 4.8.4.9.

Frequency of operative Double temperature above Living room/kitchen (%) CIBSE Guide A overheating limit (%) Singleoccupancy bedroom - base case (%) – free-running Double bedroomBase - base case (%) 26oC during hours mode. case Living room/kitchen - base case (%) and all scenarios – East flat.

Frequency of OT >26℃ (%) Mixed mode

0

C

6

12%

4

8%

2 0

3% B

C

D

E

4% 0%

Cooling loads (kWh/m2) Heating loads (kWh/m2) Figure 4.8.4.13.

Annual heating and cooling loads + frequency Single bedroom (%) Double bedroom (%) of operative temperature above 26oC during occupancy Living room/kitchen (%) CIBSE Guide A overheating limit (%) hoursSingle – mixed Base hypothetical scenarios bedroommode.

- base case (%) case and all Double bedroom - base case (%) room/kitchen - base case (%) – EastLiving flat.

Annual loads (kWh/m2) & Frequency of OT >26℃ (%) Mechanical mode

Annual loads (kWh/m2) & Frequency of OT >26℃ (%) Mechanical mode South flat

75

15.0%

60

12%

60

12.0%

45

9%

45

9.0%

30

6%

30

6.0%

15

3%

15

3.0%

0

0%

0

B

C

D

E

loads (kWh/m2) Heating loads (kWh/m2) FigureCooling 4.8.4.14.

Annual heating and cooling loads + frequency Single bedroom (%) (kWh/m2) & Frequency Double (%) Annual loads of OTbedroom >26℃ (%) of operative temperature above 26oC during occupancy Living room/kitchen (%) CIBSE Guide A overheating limithours (%) Mechanical mode Single bedroom - base case (%) case and Double bedroom - basescenarios case (%) – mechanical mode.

Base all hypothetical – Living room/kitchen - base case (%) West flat North flat.

75

kWh/m2

60

kWh/m2

6

Annual loads

45

& Frequency of OT >26℃ (%) Mixed mode South flat

30

B

C

9%

D

E

3% 12.0% 0%

8.0%

loads (kWh/m2) Heating loads (kWh/m2) FigureCooling 4.8.4.16.

Annual heating and cooling loads + frequency Single bedroom (%) Double bedroom (%) 4.0% of2 operative temperature above 26oCCIBSE during hours Living room/kitchen (%) Guide Aoccupancy overheating limit (%) 3.…

Single bedroom - base case (%) Double bedroom - base case (%) – mechanical mode.

Base case and all hypothetical scenarios – Living room/kitchen - base case (%) 0 0.0% West flat. B C D E

Cooling loads (kWh/m2) Double bedroom 1 (%) Living room/kitchen (%) Single bedroom - base case (%) Living room/kitchen - base case (%)

B

C

D

E

0.0%

Figure 4.8.4.15.

Annual heating and cooling loads + frequency Cooling loads (kWh/m2) Heating loads (kWh/m2) Double bedroom 1 (%) Double (%) Annual loads (kWh/m2) &above Frequency of OTbedroom >26℃2(%) of operative temperature 26oC during occupancy Living room/kitchen (%) CIBSE Guide A overheating limit (%) Mechanical mode bedroom - base case (%) Double bedroom base case (%) hoursSingle – mechanical mode.

Base case and all -hypothetical Living room/kitchen - base case (%) East flat scenarios – South flat.

12%

6%

15 0

4

15%

(kWh/m2)

kWh/m2

15%

kWh/m2

kWh/m2

North flat

75

75

15%

60

12%

45

9%

30

6%

15

3%

0

B

C

D

E

0%

Cooling loads (kWh/m2) Heating loads (kWh/m2) Figure 4.8.4.17.

Annual heating and cooling loads + frequency Single bedroom (%) Double bedroom (%) of operative temperature above 26oC during occupancy Living room/kitchen (%) CIBSE Guide A overheating limit (%) bedroom - base case (%) Double bedroom -hypothetical base case (%) hoursSingle – mechanical mode.

Base case and all Living room/kitchen - base case (%) scenarios – East flat.

Heating loads (kWh/m2) Double bedroom 2 (%) CIBSE Guide A overheating limit (%) Double bedroom - base case (%)

71

Contribution of building elements to Embodied carbon North flat (excluding carbon storage)

100%

Contribution of90%building elements to Embodied carbon 80% flat (excluding North carboncarbon storage) Contribution of building elements to Embodied 70%carbon storage) 100% North flat (excluding Contribution of building elements to Embodied carbon 100% 60% flat (excluding carbon storage) tribution of building North elements to Embodied carbon 90% 100% North 50% flat (excluding carbon storage) f building elements to Embodied carbon 90%

rth flat (excluding carbon storage) 90% 80%

80% 70% 60%

50% 40% 30% 20%

10% 0%

70% 60%

50% 40% 30% 20%

10% 0%

40%

70%

30%

60%

20%

10%

50%

0%

40%

B or/ceiling

B floor/ceiling C envelope

envelope

party walls

partitions

C

E

75% 80% 70% 50% 60%

A / base case B 50% 25% B C floor/ceiling envelope 40% C D 0%walls envelope party 30% D E party walls partitions 20% -25% E partitions internal walls 10% internal walls

-50% 0%

C D party walls E partitions

D E partitions internal walls

E internal walls

internal walls

A / base case

B

C

Figure 4.9.2. Contribution of building -75% floor/ceiling envelope party walls carbonA (including / base case carbon B storage). C floor/ceiling

72

D

90%

10%

A / base case

B

100% 100%

20%

0%

A / base case

Figure 4.9.1. Contribution building elements to embodied Contribution ofenvelope buildingof elements carbon floor/ceiling party walls to Embodied partitions internal walls flat (excluding carbon storage) storage) (including carbon (excludingNorth carbon storage).carbon

30%

B floor/ceiling C envelope D party walls

base case

A / base case

80%

envelope

party walls

D

E

elements to embodied partitions D

internal walls E

partitions

internal walls

4.9. Embodied carbon According to Simonsen et al. (2017), the embodied carbon of low-rise residential buildings (less than 7 story) is typically less than 500 kgCO2e/m2, considering foundation, structure and enclosure.

The values in the following analytic work are lower, due to differences in the analysis frame, as detailed below.

The embodied carbon for each construction scenario was calculated and analysed against the base case construction. The building elements included in the calculations are the floor/ceiling, envelope and internal walls of the four selected flats. Doors, windows and balconies were excluded, as well as foundations.

The mass timber structure in base case and scenario C reflects the existing building construction, according to the architect’s drawings available from the planning permission. The concrete/masonry constructions scenarios do not provide a real reinforced concrete structure, as it would require a structural design and calculation, beyond the technical field of this research.

The simulated scenarios B, D and E consider a reinforced concrete slab and masonry walls, but not beams and columns. Including those missing elements in the dynamic thermal simulations would have caused an insignificant impact in the annual loads. Nonetheless, the calculation of embodied carbon is significantly affected by the volume of concrete within the constructions, as

this is a carbon-intensive material. The calculation results shall be read with this caveat.

Timber structures weight significantly less than concrete frame, therefore they require reduced foundations and a much smaller volume of concrete. However, it is also difficult to estimate the difference between foundations for those two building systems without involving structural engineering. Therefore, foundations are also excluded from the embodied carbon calculations, despite their potentially high contribution.

This research focuses on the embodied carbon of the surfaces that enclose a residential unit in a typical floor of the case study building. It includes all walls, partitions and floor/ceiling, with more attention to the envelope.

If carbon storage is excluded, the most carbonintensive constructions are the floor/ceiling comprising the structural slab – followed by the envelope (Figures 4.9.1 and 4.9.2). The absolute difference between timber and concrete-based constructions becomes very relevant if the carbon storage is included (Figures 4.9.3 to 4.9.6).

The embodied carbon from scenarios B, D and E exceeds the base case emissions by roughly 20 to 30% in all flats (Figures 4.9.7 to 4.9.10). Construction E is the most carbon intensive scenario, whereas the base case and scenario C are the lowest ones.

73

Embodied carbon per m2 construction Floor / ceiling

180

180

120

120

kgCO2/m2

kgCO2/m2

Embodied carbon per m2 construction Envelope

60 0 -60

-120

60 0 -60

B

C

base case (no carbon storage) neutral emissions scenarios (with carbon storage)

D

-120

E

base case (with carbon storage) scenarios (no carbon storage)

Figure 4.9.3. Embodied carbon per m2 – envelope.

D

E

base case (with carbon storage) scenarios (no carbon storage)

Embodied carbon per m2 construction Internal party wall

180

180

120

120

kgCO2/m2

kgCO2/m2

C

Figure 4.9.4. Embodied carbon per m2 – floor/ceiling.

Embodied carbon per m2 construction Internal wall

60 0 -60

-120

B

base case (no carbon storage) neutral emissions scenarios (with carbon storage)

60

0 -60

B

C

base case (no carbon storage) neutral emissions scenarios (with carbon storage)

D

base case (with carbon storage) scenarios (no carbon storage)

Figure 4.9.5. Embodied carbon per m2 – internal wall.

74

E

-120

B

C

base case (no carbon storage) neutral emissions scenarios (with carbon storage)

D

E

base case (with carbon storage) scenarios (no carbon storage)

Figure 4.9.6. Embodied carbon per m2 – internal party wall.

Embodied carbon per m2 GIA

Embodied carbon per m2 GIA

North flat - envelope, internal walls and floor/ceiling

North flat - envelope, internal walls and floor/ceiling

50

28.6 - 132 %

-50

B

C

D

scenarios - excluding carbon storage

scenarios - including carbon storage

base case - excluding carbon storage

base case - including carbon storage

Figure 4.9.7. Embodied carbon per m2 – North flat.

- 132 % B

E

scenarios - including carbon storage

base case - excluding carbon storage

base case - including carbon storage

Embodied carbon per m2 GIA

North flat - envelope, internal walls and floor/ceiling

150 50

28.6 - 132 % B

C

D

E

scenarios - excluding carbon storage

scenarios - including carbon storage

base case - excluding carbon storage

base case - including carbon storage

Figure 4.9.9. Embodied carbon per m2 – West flat.

-50

+ 1246 % + 30%

295.3

250

+ 1160 % + 22%

150

350

kgCO2e/m2

295.3

250

+ 1160 % + 22%

350

+ 1246 % + 30%

450

+ 1175 % + 24%

450

kgCO2e/m2

D

scenarios - excluding carbon storage

Embodied carbon per m2 GIA

-50

C

Figure 4.9.8. Embodied carbon per m2 – South flat.

North flat - envelope, internal walls and floor/ceiling

50

+ 1246 % + 30%

28.6

-50

E

+ 1160 % + 22%

150

+ 1175 % + 24%

50

295.3

250

+ 1175 % + 24%

150

350

kgCO2e/m2

295.3

250

+ 1160 % + 22%

kgCO2e/m2

350

+ 1246 % + 30%

450

+ 1175 % + 24%

450

28.6 - 132 % B

C

D

E

scenarios - excluding carbon storage

scenarios - including carbon storage

base case - excluding carbon storage

base case - including carbon storage

Figure 4.9.10. Embodied carbon per m2 – East flat.

75

Embodied carbon per m2 construction (excluding carbon storage in timber)

180

kgCO2/m2

150

+ 36 %

+ 36%

+ 44%

+ 19%

+ 15%

+ 15%

+ 44%

+ 44%

+ 75%

120 90 60

+ 45%

30

B

+ 3%

C

D

+ 3%

E

base case - external wall

base case - internal wall

base case - internal party wall

base case - floor/ceiling

scenarios - external wall

scenarios - internal wall

scenarios - internal party wall

scenarios - floor/ceiling

Figure 5.1. Embodied carbon per m2 of building element (excluding carbon storage).

Embodied carbon per m2 GIA

envelope, internal walls and floor/ceiling

150 50 -50

+ 30% + 934 %

289 250

+ 873 % + 22%

kgCO2e/m2

350

+ 884 % + 24%

450

37.5 - 105 % B

C

D

E

scenarios - excluding carbon storage

scenarios - including carbon storage

base case - excluding carbon storage

base case - including carbon storage

Figure 5.2. Weighted average of embodied carbon in the typical floor of the case study building, considering the base case and four hypothetical scenarios.

76

5.

RESEARCH OUTCOMES AND DESIGN APPLICABILITY

EMBODIED CARBON The embodied carbon studies for the base case and hypothetical scenarios show that the calculation is largely influenced by two main factors: choice of building systems and stages of the building life considered in the calculation.

The most carbon-impacting building systems are the foundations, structure and envelope. The structural components account for a large percentage of the whole building volume and weight, whereas the envelope accounts for a large surface, depending on the building compactness.

The building fabric is usually a multilayer construction that performs a protective function.

Each element within the construction plays a specific role in the interface between the internal and external environments: weatherproofing, air tightness, thermal and sound insulation, fire protection. It may also include structural elements, which potentially increases embodied carbon within the construction. This multifunctionality inherently combines a diversity of materials to respond to all those needs.

The research scenarios comprise light and heavyweight materials. The base case and scenario C are mostly lightweight, whereas scenarios B, D and E are heavyweight.

Natural fibres, such as wood, tend to be lightweight, while mineral-based materials are denser.

Nevertheless, lightweight constructions are not necessarily low-carbon. Despite the low density, mineral and polymers insulation are a driver factor of high embodied carbon in constructions that request a thick insulation layer to achieve a low U-value.

In mass timber constructions, besides the structural role, timber also provides thermal resistive

insulation, allowing for a thinner carbon-intensive insulation layer. In contrast, two essential elements drive the embodied carbon up in CLT multi-storey buildings: fire-protective plasterboards, that are currently mandatory to limit the exposed timber in residential buildings taller than five storeys; and a cement screed that provides structure-borne sound insulation and is a fire-retardant for the timber slab.

Even the most progressive building regulations for the use of timber are cautious about its flammability, due to the lack of certainty about the material limits. The adhesive used in laminated timber structures is a limiting factor to reduce the need for drylining. Technology developments are expected in this field. The fire safety standards in Germany and Austria are currently stricter for buildings taller than 4 floors, but they allow engineers and contractors to diverge from the regulations, as long as they provide satisfactory laboratory tests. The results have been compiled, generating a database that may allow further changes in the building regulations.

In the concrete/masonry scenarios, low U-values rely on a thicker insulation layer, compared to CLT constructions. Consequently, the whole constructions are very carbon-intensive. Although there is no restriction to exposed masonry, rendering or lining it contributes to improve the air tightness and provides a smoother internal finishing surface.

It is clear that all the technical and regulation requirements for the envelope make it difficult to deliver a low-carbon construction. The comparison between the base case and construction scenarios confirms that concrete/masonry constructions are more carbon-intensive than mass timber (Figure 5.1). The difference is more pronounced if the carbon storage is included (Figure 5.2).

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OPERATIONAL CARBON The operational carbon emissions were calculated based on the annual loads for space cooling, in energy per square meter, and converted to mass of equivalent carbon dioxide emissions per square meter. The conversion factor is based on the electricity generation in 2019, 1 kWh = 0.2556 kgCO2e, according to the UK Government (Department for Business, Energy and Industrial Strategy, 2019).

The total operational carbon of a building is calculated according to its lifespan. The Greater London Authority’s policy on carbon offsets is based on a 30-year building lifetime, which is also the period estimated by EN 15978 and BREEAM (RICS, 2017). However, according to the Royal Institute of Chartered Surveyors, RICS, many building elements have a much longer lifespan (Papakosta and Sturgis, 2017), suggesting that a 60-year lifetime is reasonable for whole-life carbon assessments.

The global warming potential usually refers to a 100-year period. Although a 30-year time does not reflect the reality of buildings, the lifetime of many elements is considerably shorter.

This research analyses three lifespans found in literature: 30, 60 and 100 years. In shorter lifetimes the embodied carbon is more relevant, so a 30-year period pushes designers, engineers and contractors to pursue greater reductions in the whole-life carbon.

The operational carbon emissions calculated from simulations of mixed and mechanical mode are not significantly affected by changes in the construction, but the building orientation was a major influencer in the annual loads.

The glazing surfaces of the studied building are not shaded, and, despite the flats’ dual aspect, all rooms have a single-sided ventilation strategy. These design features provide very different conditions for heat gains and dissipation, depending on the flats’ orientation and context obstructions. The South flat is exposed to more solar radiation throughout the year, resulting in annual cooling loads 28% higher than verified in the other flats. The total annual

loads in this unit (heating and cooling) exceed the other flats by 20%.

WHOLE-LIFE CARBON This study does not include the end of life stage, due to a large number of variables influencing the reuse, recycling and disposal for each building material.

Although forests and wood are important carbon sinks, they release GHG when incinerated or decomposed, cancelling the carbon sequestration.

Recognized methodologies of whole-life carbon assessment recommend that timber carbon storage be included in embodied carbon calculations only if the end of life is part of the analysis.

The timber industry claims that carbon storage should be included in embodied carbon calculations, as the renovation rate of managed forests is enough to keep the balance between carbon storage and emissions from the end of life stage.

The sum of embodied and operational carbon shows a relevant difference between timber and concrete-based constructions (Figures 5.3 and 5.4) in a 30-year lifespan. If carbon storage is excluded, the concrete-based constructions emissions exceed the timber scenarios by roughly 10%. If carbon storage is included, this number raises to approximately 72%.

In a 60-year lifespan, concrete buildings emit 6% more CO2e than timber, carbon storage excluded.

Including it raises this number to 37% (Figures 5.5 and 5.6).

In a 100-year lifespan, the concrete construction emissions are only slightly higher than CLT’s if carbon storage is excluded but remain roughly 22% if carbon storage is included (Figure 5.7 and 5.8).

This calculation has some limitations due to the research frame and available information. The absence of foundations in all scenarios and the lack of some structural elements in the concrete constructions result in low embodied carbon in concrete scenarios. Despite those caveats, timber constructions are proven to be lower in carbon even in very long lifespans.

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Considering that a mass timber structure weighs up to 80% less than concrete frame, the foundations in concrete structure scenarios would be considerably more massive and carbon-intensive than timber, even excluding the carbon storage.

THERMAL COMFORT, CONSTRUCTIONS PROPERTIES AND CARBON EMISSIONS This research analysed the operational carbon emissions from the energy demand for space conditioning, the regulated loads. The dynamic thermal simulations show a slight difference in loads for different construction scenarios in both mixed and mechanical modes. Although timber constructions recorded a lower frequency within thermal comfort and a higher risk of overheating during the warm season, the concrete constructions are also prone to high operative temperatures even at mild external temperatures in summer (Figure 5.9).

The projections for London climate indicate an increase in cooling degree days, but heating will still be the prevailing demand.

lie in their high heat capacity. The efficiency of this passive thermal strategy relies on exposing the thermal mass surface indoors so that in warm conditions it behaves as a heat sink. The heat absorbed during daytime is released at night, so an effective night-time ventilation is essential to dissipate heat and avoid overheating at sleeping hours and during the next day. The control of solar gains in summer is also crucial to limit the amount of heat absorbed by high-capacity elements.

The analysed building envelope is mostly unshaded, allowing excessive heat gains in summer, especially in the south and west aspects. The opportunities for heat dissipation are limited, as the natural ventilation strategy for all rooms is single-sided.

The simulations show improvements in the concrete structure scenarios thermal comfort, but the absolute temperatures achieved are still high.

Maximising the exposed thermal mass in the walls (scenario E) has a negligible impact on the thermal comfort, and annual loads, compared to the effect of exposing only the concrete ceiling (scenario D).

Moreover, the addition of cement render to walls increases the embodied carbon.

In the cold season, timber and concrete constructions’ response is similar, which is The hypothesis that thermal mass would result attributed to the resistive insulation layers that in lower annual loads and, consequently, lower provide satisfactory thermal transmittance, operational carbon emissions was not confirmed.

SummerPart temperature profile - free running according to the Building Regulations L. The reduction was negligible and neutralized East flat - Single bedroom

temperature (°C)

Despite having the same U-values, timber and concrete constructions differ in terms of thermal mass, which has an impact on the radiant heat transfer 35.0 and so in the thermal amplitudes in a room. This is markedly more relevant in warm than in cold seasons.

25.0

by the high embodied carbon in heavyweight constructions. This may be attributed to other design variables that contribute to thermal comfort and related energy demand: the building shape and orientation, the size of glazing surfaces, envelope shadings, and effective ventilation strategies.

Summer temperature - free running The analysis suggests that thermal comfort and The thermal benefits of heavyweight constructions profile East flat - Single bedroom

35.0

15.0

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5.0

25.0

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BS EN 15251 adaptive comfort band OT - scenario A CIBSE TM52 - Tmax

External temperature CIBSE TM59 night threshold OT - scenario E

Figure 5.9. Warm season temperature profile of the free-running mode. The lowest and highest thermal mass constructions are depicted (base case and scenario E) - East flat single bedroom (west facing room).

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energy demand in timber constructions may be improved by adding a certain amount of thermal mass attached to the ceiling. Further studies must be carried out to determine the right proportion of this passive radiators. Technologies such as phase change materials can be explored to avoid the use of carbon intensive materials, such as cement.

Nevertheless, a proper environmental design is the most important action to provide comfortable conditions at low energy demand in both timber and concrete constructions, maximise the free running period and even eliminate the need for active cooling. The research findings are aligned with the research developed by Ferk at al. (2016), concluding that shadings and ventilation are a major concern to provide thermal comfort and minimise operational carbon emissions in all types of constructions, provided that the fabrics follow a minimum standard for energy efficiency.

In contrast, timber structures result in low embodied carbon emissions even if the carbon sequestration is excluded.

Besides the GHG emissions, further studies comparing the environmental impact of buildings should consider the life-cycle of different constructions and building systems. The exhaustion of non-renewable natural resources, changes in land use, and contamination of ecosystems may cause irreversible damages to the environment, despite not emitting GHG.

structure and other purposes. The development of timber technologies in the latest decades expanded the possibilities for timber application, including mid-rise multi-storey buildings. The mass timber technology was created in Central Europe and has been applied mostly in cold or temperate climates.

Not surprisingly, most academic studies about the thermal response of mass timber envelopes are focused on those climates.

The contribution of solar gains may be even more important in other latitudes or climate zones, so the analysis of distinction orientations is very relevant to determine the eventual energy demand for space conditioning.

The construction scenarios should be tailored according to the typical building systems of the studied context. This variable may have an impact in the building thermal response, and so in the operational carbon, but also in the embodied carbon emissions.

The set points for mechanical systems and control of apertures for natural ventilation is also dependant on the climate context. Adaptive thermal comfort relies on the occupants’ previous experience, so the tolerance to warm and cold temperatures and the need to active conditioning the spaces varies largely throughout different locations.

APPLICABILITY The climate crisis pushes all economic sectors to decarbonise their activities in the next three decades. The energy matrix is a key factor to decrease carbon emissions as the energy demand is increasingly high, likewise the urbanisation rate.

The shift from fossil fuels to renewable energy have been incentivised and gradually implemented.

However, the IPCC and CCC reports claim that a reduction in emissions must be combined with carbon sequestration to limit global warming to 1.5oC above pre-industrial levels.

Concerning emissions from the construction sector, many countries have been tightening their building regulations to deliver energy efficient buildings. The materials used to achieve it may vary considerably in terms of environmental impact.

Timber has been used in traditional construction in a diversity of climate contexts. The sustainable management of forests may provide carbon storage and a variety of timber species to be explored for 81

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6.

CONCLUSION

The research presented a literature review and analytical studies to assess the operational and embodied carbon in mass timber mid-rise residential buildings, compared to typical concrete/ masonry constructions. It concludes that early stage design decisions have stronger impact in buildings energy demand than the construction properties, provided that the fabrics comply with the energy efficiency recommended by building regulations.

The presence of thermal mass in the construction provides improvements in thermal comfort during the warm season, but the control of solar gains and heat dissipation is way more relevant to maximise the free running mode and reduce operational carbon emissions.

The study is presented in the following sections: INTRODUCTION This section presents an overview of the research justification, questions, hypothesis and methodology.

THEORETICAL BACKGROUND The literature review provides an overview on the key issues that motivated the research question and guided the analysis: - the urbanisation trend and population growth; - climate crisis, GHG emissions and global warming due to anthropogenic actions; - the contribution of construction and buildings to the increase in energy demand and global warming; - policies, initiatives and building regulations to decarbonize the building sector in the UK - whole-life carbon in buildings: embodied and

operational emissions - operational energy: thermal comfort and annual heating and cooling loads - timber as a low carbon material: potentialities and constraints CONTEXT AND PRECEDENTS London current climate analysis and projections to 2050 provide evidence that buildings should be resilient to cope with changes in temperature patterns and solar radiation intensity. The design should allow the occupants’ adaptability to maximise the free running operation in both cold and warm seasons, predicting possible changes in behaviour and increase in cooling degree days.

The review of built precedents explored the stateof-the-art of CLT residential buildings in the UK, emphasising the reduced embodied carbon.

The theoretical precedents compare the climate response and thermal performance of lightweight and heavyweight constructions, analysing typical residential typologies. The studies also investigate the increase or reduction in shading and ventilation, finding out that those variables are more impacting to thermal comfort and operational carbon emissions than thermal mass in the construction.

The impact of all design variables in annual loads and adaptive thermal comfort is more relevant in the warm season than in the cold period of the year.

The analysis of two CLT mid-rise residential buildings in London shows that the envelope influences the building exposure to solar gains and opportunities to natural ventilation, but the urban context may affect the indoor environmental conditions as well.

The brick-clad building shows less fluctuation in

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temperatures, whereas the wood pulp-clad one records higher temperatures and occurrence of overheating.

ANALYTIC WORK The analytic studies aimed to determine the embodied and operational carbon through dynamic thermal analyses, considering the weather data projected to 2050 (IPCC medium-emissions scenario).

The base case is an existing CLT mid-rise residential building in the London Borough of Hackney and the analysis compares it to another four construction scenarios. Four typical flats were selected to provide a comprehensive analysis and expand the study applicability. The units have similar layouts and spatial proportions, but different orientations and consequently, different exposure to solar radiation and prevailing winds. Despite the constant U-values, light and heavyweight constructions were simulated – mass timber and concrete structures.

The scenarios explored the exposure of thermal mass in the ceiling and walls.

The operational energy demand for space cooling was converted to carbon equivalent emissions based on the UK electricity matrix in 2019 (1 kWh = 0.2556 kgCO2e). The research compares the thermal comfort and energy demand of the five scenarios in three operation modes: free running, mixed mode and mechanical mode. The thermal comfort analysis is based on the British standard EN 15251 thermal comfort criteria, and the overheating assessment is based on CIBSE TM52 and TM59.

The different constructions provide satisfactory thermal conditions in the cold season, but different responses to warm temperatures.

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In the free running mode, the operative temperatures in summer may exceed the comfort band upper limit in all construction scenarios. In the timber construction scenarios, there is a strong correlation between the external and internal temperature. Overheating may occur even when the external temperature ranges from 20 to 23oC. In contrast, the higher heat capacity in the concrete/ masonry constructions contributes to keep indoor temperatures more stable and reduce the risk of overheating. If the thermal mass is exposed in the ceiling, the operative temperatures during heat waves may be 3K lower than in the base case.

However, the exposed concrete slabs provide only -1K difference from the timber scenario. The high solar gains - especially in the south aspect – and the limited opportunities for natural ventilation influence the thermal mass potential to reduce thermal amplitudes. This limitation is attributed to the absence of shading devices and the single sided ventilation. The only shaded room is a double bedroom in the south aspect of the south flat. In the hottest hour of a warm summer week, the operative temperature in this room is 1K lower than in a similar south facing double bedroom in the north flat, which is not shaded.

The annual loads for space conditioning in mixed and mechanical mode are not significantly affected by changes in the construction. The energy demand with the exposed concrete slab (scenarios D and E) is roughly 3.5% lower than in the base case.

Despite the low loads in the mixed mode, there is a high frequency of thermal discomfort in all scenarios.

The south flat’s annual loads in the mechanical

mode – 66.9 kWh/m2 - are 20% higher than simulated in the other flats – roughly 56 kWh/m2.

The embodied carbon was calculated based on a cradle-to-gate database. There is controversy about carbon sequestration in wood, considering that emissions are inevitable at the end of life stage.

This research discusses the impact of including and excluding the carbon storage from the embodied carbon, putting the wood life-cycle into a wider perspective that includes forests renovation rate. If carbon storage is excluded, mineral-based constructions (scenarios B, D and E) exceed the mass timber constructions embodied carbon by 22 to 30%. If carbon storage is included, this number raises to close to 900%.

OUTCOMES AND APPLICABILITY This section presents the results of whole-life carbon for a typical floor in mid-rise residential building.

The research frame excludes foundations, glazing elements and roofs. It focuses on the surfaces that enclose the residential units: the envelope, floor/ ceiling, internal walls and partitions.

The final results combine the operational carbon emissions from regulated loads in mechanical mode and the embodied carbon for both options for carbon storage. The building lifespan influences the ratio between embodied and operational emissions. If carbon storage is excluded, the concrete-based constructions emissions exceed the base case by roughly 10% in a 30-year lifetime, the most used parameter. If carbon storage is included, this number raises to approximately 72%. In a 60year lifespan, concrete buildings emit 6% more CO2e than the base case in CLT, carbon storage excluded. Including it raises this number to 37%.

This research does not include the embodied carbon in foundations. Considering that a concrete frame issignificantly heavier than mass timber, concrete volume in the foundations for timber will be much less carbon-intensive.

CONCLUSION The low thermal mass in timber influences the thermal comfort even in low U-values constructions.

In lightweight buildings, such as mass timber constructions, the contribution of early stage design variables such as orientation, compactness and design of openings is proven to be even more relevant to provide comfortable conditions at low energy demand, minimising operational carbon emissions from space conditioning. Heavyweight constructions may provide more stable temperatures indoors, but at intensive-carbon costs.

Further explorations using the research proposed methodology could include a comparison of the use of CLT in mid-rise residential buildings in different The comparison between different structural and building systems contributes to the debate and applicability of a considerably new structural system – cross laminated timber – and its response to the UK climate. The methodology of this research is applicable to investigate embodied and operational carbon emissions in buildings, aiming to pursue the minimum environmental impact and provide the maximum thermal comfort in each context.

Different building typologies could be explored furthermore, as well as testing design different envelopes and orientations, also contributing to the incipient academic research on the CLT wholelife carbon.

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APPENDIX

8.1. Conditions for dynamic thermal simulations in EDSL TAS

North flat Living room / Kitchen Single bedroom Double bedroom Bathroom Bathroom (ensuite) Corridor

Area (m2) 25.7 8.4 11.8 4.2 3.3 6

Volume (m3) 65.5 21.4 30.1 10.7 8.4 15.3

South flat Living room / Kitchen

Area (m2) 33.6 8.6 12.8 13.1 5.1 3.2 11.8

Volume (m3) 85.7 21.9 32.6 33.4 13.0 8.2 30.1

East flat Living room / Kitchen Single bedroom Double bedroom Bathroom Corridor

Area (m2) 25.9 8 14.2 5.5 8.5

Volume (m3) 66.0 20.4 36.2 14.0 21.7

West flat Living room / Kitchen Single bedroom Double bedroom Bathroom Bathroom (ensuite) Corridor

Area (m2) 23.8 9.3 14.1 4.3 3.2 11.8

Volume (m3) 60.7 23.7 36.0 11.0 8.2 30.1

average area Bedroom_L Bedroom_S Living room / kitchen S Living room / kitchen NWE

Area (m2) 13.2 8.6 33.6 25.1

Volume (m3) 33.7 21.9 85.7 64.1

Single bedroom Double bedroom 1 Double bedroom 2 Bathroom Bathroom (ensuite) Corridor

floor-to-ceiling height (m) 2.55 Fresh air supply (l/s pp) 8

ACH 1.7 1.3 1.0 0.9

91

Single bedroom Double bedroom Bathroom Bathroom (ensuite) Corridor

average area Bedroom_L Bedroom_S Living room / kitchen S Living room / kitchen NWE Bathroom Windows Bathroom en suite Top hung Corridor Top hung

9.3 14.1 4.3 3.2 11.8

Area (m2) 13.2 8.6 33.6 25.1 4.8 3.2 9.5

23.7 36.0 11.0 8.2 30.1

Volume (m3) 33.7 21.9 85.7 64.1 12.2 width 8.2 0.9 24.3 0.6

height 1.3 1.3

ACH 1.7 1.3 1.0 0.9 2.4 pane area 3.5 1.17 1.2 0.78

opening width 0.35 0.35

opening area 0.77 0.665

peak load (W) peak load per unit area number of opening opening occupants Occupancy Heat gain profilewidth sensible latent latent width area opening % Windows height pane area sensible 1 Single bedroom 75 55 8.7 6.4 Top hung 0.9 1.3 1.17 0.35 0.77 66% 2 Double bedroom 150 1.3 110 0.78 11.4 8.3 Top hung 0.6 0.35 0.665 85% 2 Living room / Kitchen 150 110 6.0 4.4 3 Living room / Kitchen 225 165 6.7 4.9 peak load (W) peak load per unit area 70% number of opening opening opening opening % to achieve Fresh opening area to achieve opening width opening 1Occupancy Bathroom 75 latent 55sensible 15.7 11.5 Heat gain profile sensible latent sensible occupants widthair area opening % width opening % air supply Fresh air supply Windowsarea width height pane area for fresh e area 1 Bathroom en suite 75 55 23.2 17.0 1 Single bedroom 75 55 8.7 6.4 6.1 0.9 1.3 0.005 1.17 0.35 0.77 66% 17 0.35Top hung0.77 66% 0.43% 0.002 1 bedroom Corridor 75 110 55 11.4 7.9 5.8 2 Double 150 8.3 8.0 0.6 1.3 0.005 0.78 0.35 0.665 85% 78 0.35Top hung0.665 85% 0.64% 0.003 2 Living room / Kitchen 150 110 6.0 4.4 (W) peak load per base load 3 Living room Equipment / Kitchen heat gain 225 peak load (W) 165 base load 6.7 4.9unit area peakper load per unit area 70% load per unit 70% load per unit area peak load (W) 50% load unit area number ofarea 80 55 10 15.7 9.3 1.2 1 Bathroom Single bedroom 75 11.5 Occupancy Heat gain profile sensible latent sensible sensible latent sensible sibleoccupants latent sensible latent latent 80 55 10 23.2 6.1 0.8 1 Bathroom enDouble suite bedroom 75 17.0 1 6.4Single bedroom 55 8.7 6.4 6.1 .7 6.1 4.575 Living room / Kitchen - 6-8pm 450 55 17.9 1 Corridor 75 7.9 5.8 2 8.3Double bedroom 110 11.4 8.3 8.0 1.4 8.0 5.8150 5.7 4.2 Living room / Kitchen - 8-10pm 200 8.0 85 3.4 2 4.4Living room / Kitchen 150 110 6.0 4.4 .0 Livinggain room / Kitchen - 9am-6pm Equipment heat peak load (W) base load (W) peak load per unit area base load 110 165 4.4 3 4.9Living room / Kitchen 225 6.7 4.9 .7 Living room / Kitchen - 10-12pm 80 Single bedroom 10 9.3 1.2 1 11.5Bathroom 75 55 15.7 11.5 5.7 Living room / Kitchen - 6-8pm 450 10 13.4 Double bedroom 80 6.1 0.8 1 Bathroom en suite 75 55 23.2 17.0 3.2 17.0 room / Kitchen - 8-10pm 200 6.0 Living room Living / Kitchen - 6-8pm 450 17.9 85 7.9 2.5 1 5.8Corridor 75 55 5.8 .9 room / Kitchen - 9am-6pm 200 Living room Living / Kitchen - 8-10pm 8.0 110 85 3.3 3.4 room / Kitchen - 10-12pm Living room Living / Kitchen - 9am-6pm Equipment heat gain peak 110 load (W) base load (W) peak load 4.4 per unit area base load er unit area base load Living room / Kitchen - 10-12pm 80 10 9.3 1.2 .3 1.2Single bedroom Living room / Kitchen - 6-8pm 450 13.4 80 10 6.1 0.8 .1 0.8Double bedroom Living room / Kitchen - 8-10pm 200 6.0 85 2.5 Living room / Kitchen - 6-8pm 450 17.9 7.9 Living room / Kitchen - 9am-6pm 110 3.3 Living room / Kitchen - 8-10pm 200 8.0 .0 85 3.4 3.4Living room / Kitchen - 10-12pm Living room / Kitchen - 9am-6pm 110 4.4 .4 Living room / Kitchen - 10-12pm opening opening opening % to achieve Fr opening Living room / Kitchen - 6-8pm 450 13.4 3.4 area opening width % area air supply opening % width height width pane area heightwidth pane Windows Living room / Kitchen - 8-10pm 200 6.0area .0 85 2.5 2.5Top hung 0.9 1.3 1.17 0.77 66% 0.43% 0.9 1.3 0.35 1.17 0.35 0.77 66% Living room / Kitchen - 9am-6pm 3.3 .3 0.6 1.3 110 0.78 0.35 0.665 85% 0.64% Top hung 0.6 1.3 0.78 0.35 0.665 85% Living room / Kitchen - 10-12pm

free running mode peak load (W) mechanical peak load (W) peak load per unit areamixed peak mode load per unit area70% load per unit area 70% number of value set back value set back value set back band upancy Heat gain profile sensible latent sensible sensible latentlatent latent Occupancy Heat gain profile sensible deadsensible latent sensible occupants Upper limit 150 150 24 150 26 150 24 droom 1 75 55 8.7 6.1 4.5 6.1 Single bedroom 75 55 6.4 8.7 6.4 Lowerbedroom limit -50150 -50 5 511.4 228.3 edroom 2 110 20 150 11.4 8.0 5.8 8.0 Double 110208.3 m / Kitchen 110 150 6.0 2 Living room / Kitchen 150 110 4.4 6.0 4.4 m / Kitchen 225 165 6.7 4.9 3 Living92 room / Kitchen 225 165 6.7 4.9 m 75 55 15.7 1 Bathroom 75 55 11.5 15.7 11.5 m en suite1 75 55 23.2 Bathroom en suite 75 55 17.0 23.2 17.0 75 55 7.9 1 Corridor 75 55 5.8 7.9 5.8

8.2. Construction scenarios

Ceiling / Floor

External wall

Internal partition

Internal wall

Internal party wall

material plasterboard insulation air CLT - Spruce insulation screed wood flooring plasterboard plasterboard air CLT - Spruce insulation air brick plasterboard insulation plasterboard plasterboard air CLT - Spruce air plasterboard plasterboard air CLT - Spruce insulation

A. Base case - CLT thickness (mm) 12.5 50 150 140 20 50 20 12.5 12.5 25 140 60 90 115 12.5 50 12.5 12.5 25 140 25 12.5 12.5 25 100 15

U-value (W/m2.K)

0.22

0.23

0.41

0.51

0.33

93

Ceiling / Floor

External wall

Internal partition

Internal wall

Internal party wall

94

material plasterboard insulation air Concrete insulation screed wood flooring plasterboard brick insulation brick plasterboard insulation plasterboard plasterboard block insulation block plasterboard plasterboard block insulation block plasterboard

B. Concrete thickness (mm) 12.5 75 100 140 20 50 20 12.5 115 100 115 12.5 50 12.5 12.5 105 22 105 12.5 12.5 105 50 105 12.5

U-value (W/m2.K)

0.22

0.22

0.41

0.53

0.33

Ceiling / Floor

External wall

Internal partition

Internal wall

Internal party wall

material CLT - Spruce insulation screed wood flooring plasterboard plasterboard air CLT - Spruce insulation air brick plasterboard insulation plasterboard plasterboard air CLT - Spruce air plasterboard plasterboard air CLT - Spruce insulation CLT - Spruce air plasterboard

C. Exposed CLT thickness (mm) 140 75 50 20 12.5 12.5 25 140 60 90 115 12.5 50 12.5 12.5 25 140 25 12.5 12.5 25 100 15 100 25 12.5

U-value (W/m2.K) 0.22

0.23

0.41

0.51

0.33

95

Ceiling / Floor

External wall

Internal partition

Internal wall

Internal party wall

96

material Concrete insulation screed wood flooring plasterboard air brick insulation brick plasterboard insulation plasterboard plasterboard air block insulation block air plasterboard plasterboard air block insulation block air plasterboard

D. Exposed Thermal mass thickness (mm) U-value (W/m2.K) 140 80 0.22 50 20 12.5 25 0.22 115 100 115 12.5 0.41 50 12.5 12.5 25 105 0.53 25 105 25 12.5 12.5 25 105 0.33 50 105 25 12.5

Ceiling / Floor

External wall

Internal partition

Internal wall

Internal party wall

material Concrete insulation screed wood flooring cement rendering brick insulation brick plasterboard insulation plasterboard cement rendering block insulation block cement rendering cement rendering block insulation block cement rendering

E. Exposed Thermal mass thickness (mm) U-value (W/m2.K) 140 100 0.22 50 20 12.5 115 0.22 100 115 12.5 0.41 50 12.5 12.5 105 0.53 25 105 12.5 12.5 105 0.33 50 105 12.5

97

8.3. Summer temperature profile - base case and scenario E Summer temperature profile - free running

External temperature

OT - scenario A

CIBSE TM59 night threshold

CIBSE TM52 - Tmax

Sep-24

Sep-17

Sep-10

Sep-03

Aug-27

Aug-20

Aug-13

Jul-30

Aug-06

Jul-23

Jul-16

Jul-09

Jul-02

Jun-25

Jun-18

Jun-11

Jun-04

May-28

May-21

May-14

May-07

35 30 25 20 15 10 5 0 May-01

temperature (°C)

North flat - Single bedroom

OT - scenario E

Summer temperature profile - free running

Sep-17

Sep-24

Sep-17

Sep-24

CIBSE TM52 - Tmax

Sep-10

CIBSE TM59 night threshold

Sep-03

OT - scenario A

Sep-10

External temperature

Sep-03

Aug-27

Aug-20

Aug-06

Aug-13

Jul-30

Jul-23

Jul-16

Jul-09

Jul-02

Jun-25

Jun-18

Jun-11

Jun-04

May-28

May-21

May-14

May-07

35 30 25 20 15 10 5 0 May-01

temperature (°C)

North flat - Double bedroom

OT - scenario E

Summer temperature profile - free running

98

External temperature

OT - scenario A

CIBSE TM52 - Tmax

OT - scenario E

Aug-27

Aug-20

Aug-13

Jul-30

Aug-06

Jul-23

Jul-16

Jul-09

Jul-02

Jun-25

Jun-18

Jun-11

Jun-04

May-28

May-21

May-14

May-07

35 30 25 20 15 10 5 0 May-01

temperature (°C)

North flat - Living room / Kitchen

Summer temperature profile - free running

External temperature

OT - scenario A

CIBSE TM59 night threshold

CIBSE TM52 - Tmax

Sep-24

Sep-17

Sep-10

Sep-03

Aug-27

Aug-20

Aug-13

Jul-30

Aug-06

Jul-23

Jul-16

Jul-09

Jul-02

Jun-25

Jun-18

Jun-11

Jun-04

May-28

May-21

May-14

May-07

35 30 25 20 15 10 5 0 May-01

temperature (°C)

West flat - Single bedroom

OT - scenario E

Summer temperature profile - free running

Sep-17

Sep-24

Sep-17

Sep-24

CIBSE TM52 - Tmax

Sep-10

CIBSE TM59 night threshold

Sep-03

OT - scenario A

Sep-10

External temperature

Sep-03

Aug-27

Aug-20

Aug-13

Jul-30

Aug-06

Jul-23

Jul-16

Jul-09

Jul-02

Jun-25

Jun-18

Jun-11

Jun-04

May-28

May-21

May-14

May-07

35 30 25 20 15 10 5 0 May-01

temperature (°C)

West flat - Double bedroom

OT - scenario E

Summer temperature profile - free running

External temperature

OT - scenario A

CIBSE TM52 - Tmax

OT - scenario E

Aug-27

Aug-20

Aug-13

Jul-30

Aug-06

Jul-23

Jul-16

Jul-09

Jul-02

Jun-25

Jun-18

Jun-11

Jun-04

May-28

May-21

May-14

May-07

35 30 25 20 15 10 5 0 May-01

temperature (°C)

West flat - Living room / Kitchen

99

Summer temperature profile - free running

External temperature

OT - scenario A

CIBSE TM59 night threshold

CIBSE TM52 - Tmax

Sep-24

Sep-17

Sep-10

Sep-03

Aug-27

Aug-20

Aug-13

Jul-30

Aug-06

Jul-23

Jul-16

Jul-09

Jul-02

Jun-25

Jun-18

Jun-11

Jun-04

May-28

May-21

May-14

May-07

35 30 25 20 15 10 5 0 May-01

temperature (°C)

East flat - Single bedroom

OT - scenario E

Summer temperature profile - free running

Sep-17

Sep-24

Sep-17

Sep-24

CIBSE TM52 - Tmax

Sep-10

CIBSE TM59 night threshold

Sep-03

OT - scenario A

Sep-10

External temperature

Sep-03

Aug-27

Aug-20

Aug-13

Jul-30

Aug-06

Jul-23

Jul-16

Jul-09

Jul-02

Jun-25

Jun-18

Jun-11

Jun-04

May-28

May-21

May-14

May-07

35 30 25 20 15 10 5 0 May-01

temperature (°C)

East flat - Double bedroom

OT - scenario E

Summer temperature profile - free running

100

External temperature

OT - scenario A

CIBSE TM52 - Tmax

OT - scenario E

Aug-27

Aug-20

Aug-13

Jul-30

Aug-06

Jul-23

Jul-16

Jul-09

Jul-02

Jun-25

Jun-18

Jun-11

Jun-04

May-28

May-21

May-14

May-07

35 30 25 20 15 10 5 0 May-01

temperature (°C)

East flat - Living room / Kitchen

Summer temperature profile - free running

External temperature

OT - scenario A

CIBSE TM59 night threshold

CIBSE TM52 - Tmax

Sep-24

Sep-17

Sep-03

Sep-10

Aug-27

Aug-20

Aug-13

Aug-06

Jul-30

Jul-23

Jul-16

Jul-09

Jul-02

Jun-25

Jun-18

Jun-04

Jun-11

May-28

May-21

May-14

May-07

35 30 25 20 15 10 5 0 May-01

temperature (°C)

South flat - Single bedroom

OT - scenario E

Summer temperature profile - free running

Sep-17

Sep-24

Sep-17

Sep-24

CIBSE TM52 - Tmax

Sep-10

CIBSE TM59 night threshold

Sep-03

OT - scenario A

Sep-10

External temperature

Sep-03

Aug-27

Aug-20

Aug-06

Aug-13

Jul-30

Jul-23

Jul-16

Jul-09

Jul-02

Jun-25

Jun-18

Jun-11

Jun-04

May-28

May-21

May-14

May-07

35 30 25 20 15 10 5 0 May-01

temperature (°C)

South flat - Double bedroom 1

OT - scenario E

Summer temperature profile - free running

External temperature

OT - scenario A

CIBSE TM52 - Tmax

OT - scenario E

Aug-27

Aug-20

Aug-06

Aug-13

Jul-30

Jul-23

Jul-16

Jul-09

Jul-02

Jun-25

Jun-18

Jun-11

Jun-04

May-28

May-21

May-14

May-07

35 30 25 20 15 10 5 0 May-01

temperature (°C)

South flat - Living room / Kitchen

101

Summer temperature profile - free running

External temperature

OT - scenario A

CIBSE TM59 night threshold

CIBSE TM52 - Tmax

Sep-24

Sep-17

Sep-10

Sep-03

Aug-27

Aug-20

Aug-13

Aug-06

Jul-30

Jul-23

Jul-16

Jul-09

Jul-02

Jun-25

Jun-18

Jun-04

Jun-11

May-28

May-21

May-14

May-07

35 30 25 20 15 10 5 0 May-01

temperature (°C)

South flat - Double bedroom 2

OT - scenario E

8.4. Cold week temperature profile - base case / scenario A Cold week temperature profile Free running mode - Scenario A North flat - Double Bedroom

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario A North flat - Living room / kitchen

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

102

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario A South flat - Single Bedroom

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario A South flat - Double Bedroom 1

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario A South flat - Double Bedroom 2

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

103

Cold week temperature profile Free running mode - Scenario A West flat - Single Bedroom

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario A West flat - Double Bedroom

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario A West flat - Living room / kitchen

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

104

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario A East flat - Single Bedroom

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario A East flat - Double Bedroom

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario A East flat - Living room / kitchen

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

105

Cold week temperature profile Free running mode - Scenario A Bedrooms

temperature (⁰C)

25 23 21 19 17 15 01-Jan

02-Jan

03-Jan

04-Jan

05-Jan

06-Jan

07-Jan

BS EN 15251 adaptive comfort band

North flat - Single bedroom

North flat - Double bedroom

South flat - Single bedroom

North flat - Double bedroom 1

South flat - Double bedroom 2

West flat - Single bedroom

West flat - Double bedroom

East flat - Single bedroom

East flat - Double bedroom

Cold week temperature profile Free running mode - Scenario A Living room / kitchens

temperature (⁰C)

25 23 21 19 17 15 01-Jan

02-Jan

03-Jan

04-Jan

05-Jan

BS EN 15251 adaptive comfort band

North flat - Living room / kitchen

West flat - Living room / kitchen

East flat - Living room / kitchen

06-Jan

07-Jan South flat - Living room / kitchen

8.5. Cold week temperature profile - scenario B Cold week temperature profile Free running mode - Scenario B North flat - Double Bedroom

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

106

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario B North flat - Living room / kitchen

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario B South flat - Single Bedroom

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario B South flat - Double Bedroom 1

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

107

Cold week temperature profile Free running mode - Scenario B South flat - Double Bedroom 2

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario B West flat - Single Bedroom

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario B West flat - Double Bedroom

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

108

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario B West flat - Living room / kitchen

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario B East flat - Single Bedroom

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario B East flat - Double Bedroom

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

109

Cold week temperature profile Free running mode - Scenario B East flat - Living room / kitchen

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario B Bedrooms

temperature (⁰C)

25 23 21 19 17 15 01-Jan

02-Jan

03-Jan

04-Jan

05-Jan

06-Jan

07-Jan

BS EN 15251 adaptive comfort band

North flat - Single bedroom

North flat - Double bedroom

South flat - Single bedroom

North flat - Double bedroom 1

South flat - Double bedroom 2

West flat - Single bedroom

West flat - Double bedroom

East flat - Single bedroom

East flat - Double bedroom

Cold week temperature profile Free running mode - Scenario B Living room / kitchens

temperature (⁰C)

25 23 21 19 17 15 01-Jan

110

02-Jan

03-Jan

04-Jan

05-Jan

BS EN 15251 adaptive comfort band

North flat - Living room / kitchen

West flat - Living room / kitchen

East flat - Living room / kitchen

06-Jan

07-Jan South flat - Living room / kitchen

8.6. Cold week temperature profile - scenario C Cold week temperature profile Free running mode - Scenario C North flat - Single Bedroom

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario C North flat - Double Bedroom

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario C North flat - Living room / kitchen

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

111

Cold week temperature profile Free running mode - Scenario C South flat - Single Bedroom

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario C South flat - Double Bedroom 1

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario C South flat - Double Bedroom 2

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

112

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario C South flat - Living room / kitchen

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario C West flat - Single Bedroom

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario C West flat - Double Bedroom

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

113

Cold week temperature profile Free running mode - Scenario C West flat - Living room / kitchen

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario C East flat - Single Bedroom

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario C East flat - Double Bedroom

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

114

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario C East flat - Living room / kitchen

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario C Bedrooms

temperature (⁰C)

25 23 21 19 17 15 01-Jan

02-Jan

03-Jan

04-Jan

05-Jan

06-Jan

07-Jan

BS EN 15251 adaptive comfort band

North flat - Single bedroom

North flat - Double bedroom

South flat - Single bedroom

North flat - Double bedroom 1

South flat - Double bedroom 2

West flat - Single bedroom

West flat - Double bedroom

East flat - Single bedroom

East flat - Double bedroom

Cold week temperature profile Free running mode - Scenario C Living room / kitchens

temperature (⁰C)

25 23 21 19 17 15 01-Jan

02-Jan

03-Jan

04-Jan

05-Jan

BS EN 15251 adaptive comfort band

North flat - Living room / kitchen

West flat - Living room / kitchen

East flat - Living room / kitchen

06-Jan

07-Jan South flat - Living room / kitchen

115

8.7. Cold week temperature profile - scenario D Cold week temperature profile Free running mode - Scenario D North flat - Single Bedroom

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario D North flat - Double Bedroom

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario D North flat - Living room / kitchen

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

116

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario D South flat - Single Bedroom

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario D South flat - Double Bedroom 1

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario D South flat - Double Bedroom 2

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

117

Cold week temperature profile Free running mode - Scenario D South flat - Living room / kitchen

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario D West flat - Single Bedroom

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario D West flat - Double Bedroom

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

118

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario D West flat - Living room / kitchen

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario D East flat - Single Bedroom

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario D East flat - Double Bedroom

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

119

Cold week temperature profile Free running mode - Scenario D East flat - Living room / kitchen

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario D Bedrooms

temperature (⁰C)

25 23 21 19 17 15 01-Jan

02-Jan

03-Jan

04-Jan

05-Jan

06-Jan

07-Jan

BS EN 15251 adaptive comfort band

North flat - Single bedroom

North flat - Double bedroom

South flat - Single bedroom

North flat - Double bedroom 1

South flat - Double bedroom 2

West flat - Single bedroom

West flat - Double bedroom

East flat - Single bedroom

East flat - Double bedroom

Cold week temperature profile Free running mode - Scenario D Living room / kitchens

temperature (⁰C)

25 23 21 19 17 15 01-Jan

120

02-Jan

03-Jan

04-Jan

05-Jan

BS EN 15251 adaptive comfort band

North flat - Living room / kitchen

West flat - Living room / kitchen

East flat - Living room / kitchen

06-Jan

07-Jan South flat - Living room / kitchen

8.8. Cold week temperature profile - scenario E Cold week temperature profile Free running mode - Scenario E North flat - Single Bedroom

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario E North flat - Double Bedroom

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario E North flat - Living room / kitchen

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

121

Cold week temperature profile Free running mode - Scenario E South flat - Single Bedroom

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario E South flat - Double Bedroom 1

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario E South flat - Double Bedroom 2

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

122

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario E South flat - Living room / kitchen

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario E West flat - Single Bedroom

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario E West flat - Double Bedroom

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

123

Cold week temperature profile Free running mode - Scenario E West flat - Living room / kitchen

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario E East flat - Single Bedroom

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario E East flat - Double Bedroom

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

124

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario E East flat - Living room / kitchen

temperature (⁰C)

23

18

13

8

3 01-Jan

02-Jan

03-Jan

BS EN 15251 adaptive comfort band

04-Jan

05-Jan

External temperature

06-Jan DBT

07-Jan MRT

OT

Cold week temperature profile Free running mode - Scenario E Living room / kitchens

temperature (⁰C)

25 23 21 19 17 15 01-Jan

02-Jan

03-Jan

04-Jan

05-Jan

BS EN 15251 adaptive comfort band

North flat - Living room / kitchen

West flat - Living room / kitchen

East flat - Living room / kitchen

06-Jan

07-Jan South flat - Living room / kitchen

Cold week temperature profile Free running mode - Scenario E Living room / kitchens

temperature (⁰C)

25 23 21 19 17 15 01-Jan

02-Jan

03-Jan

04-Jan

05-Jan

BS EN 15251 adaptive comfort band

North flat - Living room / kitchen

West flat - Living room / kitchen

East flat - Living room / kitchen

06-Jan

07-Jan South flat - Living room / kitchen

125

8.9. Warm week temperature profile - base case / scenario A Warm week temperature profile Free running mode - Scenario A North flat - Double Bedroom

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

Warm week temperature profile Free running mode - Scenario A North flat - Living room / kitchen

temperature (⁰C)

35 30

25 20 15 21-Jul

126

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

Warm week temperature profile Free running mode - Scenario A South flat - Single bedroom

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

Warm week temperature profile Free running mode - Scenario A South flat - Double Bedroom 1

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

Warm week temperature profile Free running mode - Scenario A South flat - Double Bedroom 2

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

127

Warm week temperature profile Free running mode - Scenario A West flat - Double bedroom

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

Warm week temperature profile Free running mode - Scenario A West flat - Living room / kitchen

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

Warm week temperature profile Free running mode - Scenario A East flat - Single bedroom

temperature (⁰C)

35 30

25 20 15 21-Jul

128

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

Warm week temperature profile Free running mode - Scenario A East flat - Double bedroom

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

Warm week temperature profile Free running mode - Scenario A East flat - Living room / kitchen

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

Warm week temperature profile Free running mode - Scenario A Operative temperature - Bedrooms

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

BS EN 15251 adaptive comfort band North flat - Double bedroom CIBSE TM52 - Tmax South flat - Double bedroom 2 East flat - Single bedroom

23-Jul

24-Jul

25-Jul

External temperature South flat - Single bedroom CIBSE TM52 - Tupp West flat - Single bedroom East flat - Double bedroom

26-Jul

27-Jul North flat - Single bedroom TM59 - overheating threshold South flat - Double bedroom 1 West flat - Double bedroom

129

Warm week temperature profile

Free running mode - Scenario A Operative temperature - Living room / kitchens

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

North flat - Living room / kitchen

South flat - Living room / kitchen

West flat - Living room / kitchen

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

East flat - Living room / kitchen

8.10. Warm week temperature profile - scenario B Warm week temperature profile Free running mode - Scenario B North flat - Double Bedroom

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

Warm week temperature profile Free running mode - Scenario B North flat - Living room / kitchen

temperature (⁰C)

35 30

25 20 15 21-Jul

130

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

Warm week temperature profile Free running mode - Scenario B South flat - Single bedroom

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

Warm week temperature profile Free running mode - Scenario B South flat - Double Bedroom 1

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

Warm week temperature profile Free running mode - Scenario B South flat - Double Bedroom 2

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

131

Warm week temperature profile Free running mode - Scenario B West flat - Double bedroom

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

Warm week temperature profile Free running mode - Scenario B West flat - Living room / kitchen

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

Warm week temperature profile Free running mode - Scenario B East flat - Single bedroom

temperature (⁰C)

35 30

25 20 15 21-Jul

132

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

Warm week temperature profile Free running mode - Scenario B East flat - Double bedroom

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

Warm week temperature profile Free running mode - Scenario B East flat - Living room / kitchen

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

Warm week temperature profile

Free running mode - Scenario B Operative temperature - Living room / kitchens

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

North flat - Living room / kitchen

South flat - Living room / kitchen

West flat - Living room / kitchen

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

East flat - Living room / kitchen

133

8.11. Warm week temperature profile - scenario C Warm week temperature profile Free running mode - Scenario C North flat - Single Bedroom

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

Warm week temperature profile Free running mode - Scenario C North flat - Double Bedroom

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

Warm week temperature profile Free running mode - Scenario C North flat - Living room / kitchen

temperature (⁰C)

35 30

25 20 15 21-Jul

134

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

Warm week temperature profile Free running mode - Scenario C South flat - Single bedroom

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

Warm week temperature profile Free running mode - Scenario C South flat - Double Bedroom 1

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

Warm week temperature profile Free running mode - Scenario C South flat - Double Bedroom 2

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

135

Warm week temperature profile Free running mode - Scenario C South flat - Living room / kitchen

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

Warm week temperature profile Free running mode - Scenario C West flat - Single bedroom

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

Warm week temperature profile Free running mode - Scenario C West flat - Double bedroom

temperature (⁰C)

35 30

25 20 15 21-Jul

136

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

Warm week temperature profile Free running mode - Scenario C West flat - Living room / kitchen

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

Warm week temperature profile Free running mode - Scenario C East flat - Single bedroom

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

Warm week temperature profile Free running mode - Scenario C East flat - Double bedroom

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

137

Warm week temperature profile Free running mode - Scenario C East flat - Living room / kitchen

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

Warm week temperature profile Free running mode - Scenario C Operative temperature - Bedrooms

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

BS EN 15251 adaptive comfort band North flat - Double bedroom CIBSE TM52 - Tmax South flat - Double bedroom 2 East flat - Single bedroom

24-Jul

25-Jul

26-Jul

External temperature South flat - Single bedroom CIBSE TM52 - Tupp West flat - Single bedroom East flat - Double bedroom

27-Jul North flat - Single bedroom TM59 - overheating threshold South flat - Double bedroom 1 West flat - Double bedroom

Warm week temperature profile

Free running mode - Scenario C Operative temperature - Living room / kitchens

temperature (⁰C)

35 30

25 20 15 21-Jul

138

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

North flat - Living room / kitchen

South flat - Living room / kitchen

West flat - Living room / kitchen

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

East flat - Living room / kitchen

8.12. Warm week temperature profile - scenario D Warm week temperature profile Free running mode - Scenario D North flat - Single Bedroom

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

Warm week temperature profile Free running mode - Scenario D North flat - Double Bedroom

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

Warm week temperature profile Free running mode - Scenario D North flat - Living room / kitchen

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

139

Warm week temperature profile Free running mode - Scenario D South flat - Single bedroom

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

Warm week temperature profile Free running mode - Scenario D South flat - Double Bedroom 1

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

Warm week temperature profile Free running mode - Scenario D South flat - Double Bedroom 2

temperature (⁰C)

35 30

25 20 15 21-Jul

140

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

Warm week temperature profile Free running mode - Scenario D South flat - Living room / kitchen

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

Warm week temperature profile Free running mode - Scenario D West flat - Single bedroom

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

Warm week temperature profile Free running mode - Scenario D West flat - Double bedroom

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

141

Warm week temperature profile Free running mode - Scenario D West flat - Living room / kitchen

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

Warm week temperature profile Free running mode - Scenario D East flat - Single bedroom

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

Warm week temperature profile Free running mode - Scenario D East flat - Double bedroom

temperature (⁰C)

35 30

25 20 15 21-Jul

142

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

Warm week temperature profile Free running mode - Scenario D East flat - Living room / kitchen

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

Warm week temperature profile Free running mode - Scenario D Operative temperature - Bedrooms

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

BS EN 15251 adaptive comfort band North flat - Double bedroom CIBSE TM52 - Tmax South flat - Double bedroom 2 East flat - Single bedroom

24-Jul

25-Jul

26-Jul

External temperature South flat - Single bedroom CIBSE TM52 - Tupp West flat - Single bedroom East flat - Double bedroom

27-Jul North flat - Single bedroom TM59 - overheating threshold South flat - Double bedroom 1 West flat - Double bedroom

Warm week temperature profile

Free running mode - Scenario D Operative temperature - Living room / kitchens

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

North flat - Living room / kitchen

South flat - Living room / kitchen

West flat - Living room / kitchen

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

East flat - Living room / kitchen

143

8.13. Warm week temperature profile - scenario E Warm week temperature profile Free running mode - Scenario E North flat - Single Bedroom

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

Warm week temperature profile Free running mode - Scenario E North flat - Double Bedroom

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

Warm week temperature profile Free running mode - Scenario E North flat - Living room / kitchen

temperature (⁰C)

35 30

25 20 15 21-Jul

144

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

Warm week temperature profile Free running mode - Scenario E South flat - Single bedroom

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

Warm week temperature profile Free running mode - Scenario E South flat - Double Bedroom 1

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

Warm week temperature profile Free running mode - Scenario E South flat - Double Bedroom 2

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

145

Warm week temperature profile Free running mode - Scenario E West flat - Single bedroom

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

Warm week temperature profile Free running mode - Scenario E West flat - Double bedroom

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

Warm week temperature profile Free running mode - Scenario E West flat - Living room / kitchen

temperature (⁰C)

35 30

25 20 15 21-Jul

146

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

Warm week temperature profile Free running mode - Scenario E East flat - Single bedroom

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

Warm week temperature profile Free running mode - Scenario E East flat - Double bedroom

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

Warm week temperature profile Free running mode - Scenario E East flat - Living room / kitchen

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

DBT

MRT

OT

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

147

Warm week temperature profile Free running mode - Scenario E Operative temperature - Bedrooms

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

BS EN 15251 adaptive comfort band North flat - Double bedroom CIBSE TM52 - Tmax South flat - Double bedroom 2 East flat - Single bedroom

24-Jul

25-Jul

26-Jul

External temperature South flat - Single bedroom CIBSE TM52 - Tupp West flat - Single bedroom East flat - Double bedroom

27-Jul North flat - Single bedroom TM59 - overheating threshold South flat - Double bedroom 1 West flat - Double bedroom

Warm week temperature profile

Free running mode - Scenario E Operative temperature - Living room / kitchens

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

24-Jul

25-Jul

26-Jul

27-Jul

BS EN 15251 adaptive comfort band

External temperature

North flat - Living room / kitchen

South flat - Living room / kitchen

West flat - Living room / kitchen

TM59 - overheating threshold

CIBSE TM52 - Tmax

CIBSE TM52 - Tupp

East flat - Living room / kitchen

8.14. Cold week temperature profile - OT - all scenarios Cold week temperature profile

Free running mode - Operative temperature North flat - Double Bedroom

temperature (⁰C)

25 20

15 10 5 01-Jan

03-Jan

04-Jan

05-Jan

06-Jan

07-Jan

BS EN 15251 adaptive comfort band

External temperature

OT - scenario A

OT - scenario E

OT - scenario B

OT - scenario C

OT - scenario D

148

02-Jan

Cold week temperature profile

Free running mode - Operative temperature North flat - Living room/kitchen

temperature (⁰C)

25 20

15 10 5 01-Jan

02-Jan

03-Jan

04-Jan

05-Jan

06-Jan

07-Jan

BS EN 15251 adaptive comfort band

External temperature

OT - scenario A

OT - scenario E

OT - scenario B

OT - scenario C

OT - scenario D

Cold week temperature profile

Free running mode - Operative temperature South flat - Single Bedroom

temperature (⁰C)

25 20

15 10 5 01-Jan

02-Jan

03-Jan

04-Jan

05-Jan

06-Jan

07-Jan

BS EN 15251 adaptive comfort band

External temperature

OT - scenario A

OT - scenario E

OT - scenario B

OT - scenario C

OT - scenario D

Cold week temperature profile

Free running mode - Operative temperature South flat - Double Bedroom 1

temperature (⁰C)

25 20

15 10 5 01-Jan

02-Jan

03-Jan

04-Jan

05-Jan

06-Jan

07-Jan

BS EN 15251 adaptive comfort band

External temperature

OT - scenario A

OT - scenario E

OT - scenario B

OT - scenario C

OT - scenario D

Cold week temperature profile

Free running mode - Operative temperature South flat - Double Bedroom 2

temperature (⁰C)

25 20

15 10 5 01-Jan

02-Jan

03-Jan

04-Jan

05-Jan

06-Jan

07-Jan

BS EN 15251 adaptive comfort band

External temperature

OT - scenario A

OT - scenario E

OT - scenario B

OT - scenario C

OT - scenario D

149

Cold week temperature profile

Free running mode - Operative temperature West flat - Single Bedroom

temperature (⁰C)

25 20

15 10 5 01-Jan

02-Jan

03-Jan

04-Jan

05-Jan

06-Jan

07-Jan

BS EN 15251 adaptive comfort band

External temperature

OT - scenario A

OT - scenario E

OT - scenario B

OT - scenario C

OT - scenario D

Cold week temperature profile

Free running mode - Operative temperature West flat - Double Bedroom

temperature (⁰C)

25 20

15 10 5 01-Jan

02-Jan

03-Jan

04-Jan

05-Jan

06-Jan

07-Jan

BS EN 15251 adaptive comfort band

External temperature

OT - scenario A

OT - scenario E

OT - scenario B

OT - scenario C

OT - scenario D

Cold week temperature profile

Free running mode - Operative temperature West flat - Living room/kitchen

temperature (⁰C)

25 20

15 10 5 01-Jan

02-Jan

03-Jan

04-Jan

05-Jan

06-Jan

07-Jan

BS EN 15251 adaptive comfort band

External temperature

OT - scenario A

OT - scenario E

OT - scenario B

OT - scenario C

OT - scenario D

Cold week temperature profile

Free running mode - Operative temperature East flat - Single Bedroom

temperature (⁰C)

25 20

15 10 5 01-Jan

03-Jan

04-Jan

05-Jan

06-Jan

07-Jan

BS EN 15251 adaptive comfort band

External temperature

OT - scenario A

OT - scenario E

OT - scenario B

OT - scenario C

OT - scenario D

150

02-Jan

Cold week temperature profile

Free running mode - Operative temperature East flat - Single Bedroom

temperature (⁰C)

25 20

15 10 5 01-Jan

02-Jan

03-Jan

04-Jan

05-Jan

06-Jan

07-Jan

BS EN 15251 adaptive comfort band

External temperature

OT - scenario A

OT - scenario E

OT - scenario B

OT - scenario C

OT - scenario D

Cold week temperature profile

Free running mode - Operative temperature East flat - Double Bedroom

temperature (⁰C)

25 20

15 10 5 01-Jan

02-Jan

03-Jan

04-Jan

05-Jan

06-Jan

07-Jan

BS EN 15251 adaptive comfort band

External temperature

OT - scenario A

OT - scenario E

OT - scenario B

OT - scenario C

OT - scenario D

8.15. Warm week temperature profile - OT - all scenarios Warm week temperature profile

Free running mode - Operative temperature North flat - Double Bedroom

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

BS EN 15251 adaptive comfort band OT - scenario E CIBSE TM52 - Tupp OT - scenario D

23-Jul

24-Jul

25-Jul

External temperature TM59 - overheating threshold OT - scenario B

26-Jul

27-Jul OT - scenario A CIBSE TM52 - Tmax OT - scenario C

151

Warm week temperature profile

Free running mode - Operative temperature North flat - Living room/kitchen

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

BS EN 15251 adaptive comfort band OT - scenario E CIBSE TM52 - Tupp OT - scenario D

24-Jul

25-Jul

26-Jul

External temperature TM59 - overheating threshold OT - scenario B

27-Jul OT - scenario A CIBSE TM52 - Tmax OT - scenario C

Warm week temperature profile

Free running mode - Operative temperature South flat - Single Bedroom

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

BS EN 15251 adaptive comfort band OT - scenario E CIBSE TM52 - Tupp OT - scenario D

24-Jul

25-Jul

26-Jul

External temperature TM59 - overheating threshold OT - scenario B

27-Jul OT - scenario A CIBSE TM52 - Tmax OT - scenario C

Warm week temperature profile

Free running mode - Operative temperature South flat - Double Bedroom 1

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

BS EN 15251 adaptive comfort band OT - scenario E CIBSE TM52 - Tupp OT - scenario D

24-Jul

25-Jul

26-Jul

External temperature TM59 - overheating threshold OT - scenario B

27-Jul OT - scenario A CIBSE TM52 - Tmax OT - scenario C

Warm week temperature profile

Free running mode - Operative temperature South flat - Double Bedroom 2

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

BS EN 15251 adaptive comfort band OT - scenario E CIBSE TM52 - Tupp OT - scenario D

152

23-Jul

24-Jul

25-Jul

External temperature TM59 - overheating threshold OT - scenario B

26-Jul

27-Jul OT - scenario A CIBSE TM52 - Tmax OT - scenario C

Warm week temperature profile

Free running mode - Operative temperature West flat - Double Bedroom

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

BS EN 15251 adaptive comfort band OT - scenario E CIBSE TM52 - Tupp OT - scenario D

24-Jul

25-Jul

26-Jul

External temperature TM59 - overheating threshold OT - scenario B

27-Jul OT - scenario A CIBSE TM52 - Tmax OT - scenario C

Warm week temperature profile

Free running mode - Operative temperature West flat - Living room/kitchen

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

BS EN 15251 adaptive comfort band OT - scenario E CIBSE TM52 - Tupp OT - scenario D

24-Jul

25-Jul

26-Jul

External temperature TM59 - overheating threshold OT - scenario B

27-Jul OT - scenario A CIBSE TM52 - Tmax OT - scenario C

Warm week temperature profile

Free running mode - Operative temperature East flat - Single Bedroom

temperature (⁰C)

35 30

25 20 15 21-Jul

22-Jul

BS EN 15251 adaptive comfort band OT - scenario E CIBSE TM52 - Tupp OT - scenario D

24-Jul

25-Jul

26-Jul

External temperature TM59 - overheating threshold OT - scenario B

27-Jul OT - scenario A CIBSE TM52 - Tmax OT - scenario C

Warm week temperature profile

Free running mode - Operative temperature East flat - Double Bedroom

35

temperature (⁰C)

23-Jul

30

25 20 15 21-Jul

22-Jul

BS EN 15251 adaptive comfort band OT - scenario E CIBSE TM52 - Tupp OT - scenario D

23-Jul

24-Jul

25-Jul

External temperature TM59 - overheating threshold OT - scenario B

26-Jul

27-Jul OT - scenario A CIBSE TM52 - Tmax OT - scenario C

153

Warm week temperature profile

Free running mode - Operative temperature East flat - Living room/kitchen

temperature (â °C)

35 30

25 20 15 21-Jul

22-Jul

23-Jul

BS EN 15251 adaptive comfort band OT - scenario E CIBSE TM52 - Tupp OT - scenario D

24-Jul

25-Jul

External temperature TM59 - overheating threshold OT - scenario B

26-Jul

27-Jul OT - scenario A CIBSE TM52 - Tmax OT - scenario C

8.16. Adaptive Overheating (CIBSE TM52) dalston_lane_free-running_A_check.tsd

Adaptive Overheating Report (CIBSE TM52) Building Category: Category II Report Criteria: TM52

Results Occupied Summer Hours

Max. Exceedable Hours

North flat_Bedroom_small_S North flat_Bedroom_large_S North flat_Living room / Kitchen_N South flat_Bedroom_small_N South flat_Bedroom_large_N South flat_Living Room / Kitchen_S

3672 3672 1989 3672 3672 1989

110 110 59 110 110 59

Criterion 1: #Hours Exceeding Comfort Range 98 82 12 88 58 91

South flat_Bedroom_recessed_large_S

3672

110

West_Bedroom_small_E West flat_Living Room / Kitchen_W West flat_Bedroom_large_E East flat_Bedroom_small_W East flat_Bedroom_large_W East flat_Living room / Kitchen_E

3672 1989 3672 3672 3672 1989

110 59 110 110 110 59

Zone Name

154

19.0 17.0 14.0 18.0 26.0 17.0

Criterion 3: #Hours Exceeding Absolute Limit 6 5 0 5 0 9

39

20.0

0

Pass

75 20 69 105 91 26

18.0 18.0 35.0 17.0 20.0 25.0

5 1 0 9 8 0

Fail Fail Pass Fail Fail Pass

Criterion 2: Peak Daily Weighted Exceedance

Result

Fail Fail Pass Fail Pass Fail

dalston_lane_free-running_B_check.tsd

Adaptive Overheating Report (CIBSE TM52) Building Category: Category II Report Criteria: TM52

Results Occupied Summer Hours

Max. Exceedable Hours

North flat_Bedroom_small_S North flat_Bedroom_large_S North flat_Living room / Kitchen_N South flat_Bedroom_small_N South flat_Bedroom_large_N South flat_Living Room / Kitchen_S

3672 3672 1989 3672 3672 1989

110 110 59 110 110 59

Criterion 1: #Hours Exceeding Comfort Range 51 39 6 63 19 59

South flat_Bedroom_recessed_large_S

3672

110

West_Bedroom_small_E West flat_Living Room / Kitchen_W West flat_Bedroom_large_E East flat_Bedroom_small_W East flat_Bedroom_large_W East flat_Living room / Kitchen_E

3672 1989 3672 3672 3672 1989

110 59 110 110 110 59

Zone Name

25.0 20.0 6.0 26.0 10.0 16.0

Criterion 3: #Hours Exceeding Absolute Limit 1 0 0 1 0 5

10

10.0

0

Pass

39 9 32 59 50 11

21.0 10.0 21.0 22.0 19.0 15.0

0 0 0 3 1 0

Pass Pass Pass Fail Fail Pass

Criterion 2: Peak Daily Weighted Exceedance

Result

Fail Pass Pass Fail Pass Fail

dalston_lane_free-running_C_check.tsd

Adaptive Overheating Report (CIBSE TM52) Building Category: Category II Report Criteria: TM52

Results Occupied Summer Hours

Max. Exceedable Hours

North flat_Bedroom_small_S North flat_Bedroom_large_S North flat_Living room / Kitchen_N South flat_Bedroom_small_N South flat_Bedroom_large_N South flat_Living Room / Kitchen_S

3672 3672 1989 3672 3672 1989

110 110 59 110 110 59

Criterion 1: #Hours Exceeding Comfort Range 84 72 8 75 50 71

South flat_Bedroom_recessed_large_S

3672

110

West_Bedroom_small_E West flat_Living Room / Kitchen_W West flat_Bedroom_large_E East flat_Bedroom_small_W East flat_Bedroom_large_W East flat_Living room / Kitchen_E

3672 1989 3672 3672 3672 1989

110 59 110 110 110 59

Zone Name

17.0 24.0 10.0 19.0 20.0 15.0

Criterion 3: #Hours Exceeding Absolute Limit 6 2 0 4 0 6

26

16.0

0

Pass

68 18 61 95 83 18

32.0 18.0 34.0 17.0 21.0 20.0

0 0 0 7 6 0

Pass Pass Pass Fail Fail Pass

Criterion 2: Peak Daily Weighted Exceedance

Result

Fail Fail Pass Fail Pass Fail

155 C:\\Users\\julia\\Documents\\Dalston Lane_CLT\\B. Base case_Concrete\\Free running\\dalston_lane_free-running_B_check.tsd

Page 1 of 2

dalston_lane_free-running_D_check.tsd

Adaptive Overheating Report (CIBSE TM52) Building Category: Category II Report Criteria: TM52

Results Occupied Summer Hours

Max. Exceedable Hours

North flat_Bedroom_small_S North flat_Bedroom_large_S North flat_Living room / Kitchen_N South flat_Bedroom_small_N South flat_Bedroom_large_N South flat_Living Room / Kitchen_S

3672 3672 1989 3672 3672 1989

110 110 59 110 110 59

Criterion 1: #Hours Exceeding Comfort Range 22 12 0 26 1 27

South flat_Bedroom_recessed_large_S

3672

110

West_Bedroom_small_E West flat_Living Room / Kitchen_W West flat_Bedroom_large_E East flat_Bedroom_small_W East flat_Bedroom_large_W East flat_Living room / Kitchen_E

3672 1989 3672 3672 3672 1989

110 59 110 110 110 59

Zone Name

17.0 9.0 0.0 15.0 1.0 22.0

Criterion 3: #Hours Exceeding Absolute Limit 0 0 0 0 0 0

0

0.0

0

Pass

15 3 12 35 26 6

10.0 3.0 9.0 14.0 9.0 6.0

0 0 0 0 0 0

Pass Pass Pass Pass Pass Pass

Criterion 2: Peak Daily Weighted Exceedance

Result

Pass Pass Pass Pass Pass Pass

dalston_lane_free-running_E_check.tsd

Adaptive Overheating Report (CIBSE TM52) Building Category: Category II Report Criteria: TM52

Results Occupied Summer Hours

Max. Exceedable Hours

North flat_Bedroom_small_S North flat_Bedroom_large_S North flat_Living room / Kitchen_N South flat_Bedroom_small_N South flat_Bedroom_large_N South flat_Living Room / Kitchen_S

3672 3672 1989 3672 3672 1989

110 110 59 110 110 59

Criterion 1: #Hours Exceeding Comfort Range 18 9 0 24 0 25

South flat_Bedroom_recessed_large_S

3672

110

West_Bedroom_small_E West flat_Living Room / Kitchen_W West flat_Bedroom_large_E East flat_Bedroom_small_W East flat_Bedroom_large_W East flat_Living room / Kitchen_E

3672 1989 3672 3672 3672 1989

110 59 110 110 110 59

Zone Name

14.0 8.0 0.0 14.0 0.0 21.0

Criterion 3: #Hours Exceeding Absolute Limit 0 0 0 0 0 0

0

0.0

0

Pass

13 3 8 32 25 4

9.0 3.0 8.0 12.0 9.0 4.0

0 0 0 0 0 0

Pass Pass Pass Pass Pass Pass

Criterion 2: Peak Daily Weighted Exceedance

Result

Pass Pass Pass Pass Pass Pass

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8.17. Domestic Overheating (CIBSE TM59) dalston_lane_free-running_A_check.tsd

Domestic Overheating (CIBSE TM59) Building Category: Category II

Natural Ventilation Overheating Results Criterion 2: Criterion 1: Annual Number of #Hours Night Max Occupied Max. Night Hours Summer Exceedable Exceeding Occupied Exceedable Result Exceeding Comfort Hours for Night Hours Hours Hours 26 °C for Range Bedroom Bedrooms.

Zone Name

Room Use

East flat_Bedroom_large_W

Bedroom

3672

110

91

3285

32

36

Fail

East flat_Bedroom_small_W

Bedroom

3672

110

105

3285

32

19

Pass

Bedroom

3672

110

82

3285

32

34

Fail

Bedroom

3672

110

98

3285

32

28

Pass

Bedroom

3672

110

58

3285

32

24

Pass

Bedroom

3672

110

39

3285

32

25

Pass

Bedroom

3672

110

88

3285

32

18

Pass

Bedroom

3672

110

69

3285

32

27

Pass

Bedroom

3672

110

75

3285

32

17

Pass

North flat_Bedroom_large_S North flat_Bedroom_small_S South flat_Bedroom_large_N South flat_Bedroom_recessed_ large_S South flat_Bedroom_small_N West flat_Bedroom_large_E West_Bedroom_small_E

157

dalston_lane_free-running_B_check.tsd

Domestic Overheating (CIBSE TM59) Building Category: Category II

Natural Ventilation Overheating Results

Room Use

Zone Name

Criterion 2: Criterion 1: Annual Number of Max Night Max. #Hours Occupied Night Hours Result Summer Exceedable Exceeding Occupied Exceedable Exceeding Comfort Hours for Night Hours Hours Hours 26 °C for Bedroom Range Bedrooms.

Bedroom East flat_Bedroom_large_W 3672 110 50 3285 32 32 Bedroom East flat_Bedroom_small_W 3672 110 59 3285 32 17 Bedroom North flat_Bedroom_large_S 3672 110 39 3285 32 26 Bedroom North flat_Bedroom_small_S 3672 110 51 3285 32 19 Bedroom South flat_Bedroom_large_N 3672 110 19 3285 32 21 South Bedroom 3672 110 10 3285 32 18 flat_Bedroom_recessed_large_S Bedroom South flat_Bedroom_small_N 3672 110 63 3285 32 16 Bedroom West flat_Bedroom_large_E 3672 110 32 3285 32 21 Bedroom West_Bedroom_small_E 3672 110 39 3285 32 17 *Zone name's that have an orange coloured font are bedrooms which do not have 24/7 365 days a year occupancy, as per the TM59

Pass Pass Pass Pass Pass Pass Pass Pass Pass

dalston_lane_free-running_C_check.tsd

Domestic Overheating (CIBSE TM59) Building Category: Category II

Natural Ventilation Overheating Results Criterion 2: Criterion 1: Annual Number of Occupied Max. #Hours Night Max Night Hours Summer Exceedable Exceeding Occupied Exceedable Result Exceeding Hours Hours Comfort Hours for Night Hours 26 °C for Range Bedroom Bedrooms.

Zone Name

Room Use

East flat_Bedroom_large_W East flat_Bedroom_small_W North flat_Bedroom_large_S North flat_Bedroom_small_S South flat_Bedroom_large_N

Bedroom Bedroom Bedroom Bedroom Bedroom

3672 3672 3672 3672 3672

110 110 110 110 110

83 95 72 84 50

3285 3285 3285 3285 3285

32 32 32 32 32

41 21 37 28 28

Fail Pass Fail Pass Pass

South flat_Bedroom_recessed_large_S

Bedroom

3672

110

26

3285

32

28

Pass

South flat_Bedroom_small_N West flat_Bedroom_large_E West_Bedroom_small_E

Bedroom Bedroom Bedroom

3672 3672 3672

110 110 110

75 61 68

3285 3285 3285

32 32 32

18 29 17

Pass Pass Pass

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dalston_lane_free-running_D_check.tsd

Domestic Overheating (CIBSE TM59) Building Category: Category II

Natural Ventilation Overheating Results

Zone Name

Room Use

Criterion 2: Criterion 1: Annual Number of Max Night Max. #Hours Occupied Night Hours Result Summer Exceedable Exceeding Occupied Exceedable Exceeding Hours Comfort Hours for Night Hours Hours 26 °C for Bedroom Range Bedrooms.

Bedroom East flat_Bedroom_large_W 3672 110 26 3285 32 38 Fail Bedroom East flat_Bedroom_small_W 3672 110 35 3285 32 18 Pass Bedroom North flat_Bedroom_large_S 3672 110 12 3285 32 28 Pass Bedroom North flat_Bedroom_small_S 3672 110 22 3285 32 21 Pass Bedroom South flat_Bedroom_large_N 3672 110 1 3285 32 21 Pass Bedroom South flat_Bedroom_recessed_large_S 3672 110 0 3285 32 17 Pass Bedroom South flat_Bedroom_small_N 3672 110 26 3285 32 17 Pass Bedroom West flat_Bedroom_large_E 3672 110 12 3285 32 23 Pass Bedroom West_Bedroom_small_E 3672 110 15 3285 32 17 Pass *Zone name's that have an orange coloured font are bedrooms which do not have 24/7 365 days a year occupancy, as per the TM59 guidance.

dalston_lane_free-running_E_check.tsd

Domestic Overheating (CIBSE TM59) Building Category: Category II

Natural Ventilation Overheating Results

Zone Name

Room Use

Criterion 2: Criterion 1: Annual Number of Max Night Max. #Hours Occupied Night Hours Result Summer Exceedable Exceeding Occupied Exceedable Exceeding Hours Comfort Hours for Night Hours Hours 26 °C for Bedroom Range Bedrooms.

Bedroom East flat_Bedroom_large_W 3672 110 25 3285 32 42 Fail Bedroom East flat_Bedroom_small_W 3672 110 32 3285 32 19 Pass Bedroom North flat_Bedroom_large_S 3672 110 9 3285 32 31 Pass Bedroom North flat_Bedroom_small_S 3672 110 18 3285 32 23 Pass Bedroom South flat_Bedroom_large_N 3672 110 0 3285 32 23 Pass Bedroom South flat_Bedroom_recessed_large_S 3672 110 0 3285 32 17 Pass Bedroom South flat_Bedroom_small_N 3672 110 24 3285 32 17 Pass Bedroom West flat_Bedroom_large_E 3672 110 8 3285 32 24 Pass Bedroom West_Bedroom_small_E 3672 110 13 3285 32 18 Pass *Zone name's that have an orange coloured font are bedrooms which do not have 24/7 365 days a year occupancy, as per the TM59 guidance.

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8.18. Frequency of overheating - comparison of all scenarios Overheating

Overheating

North Flat - Living room / kitchen

South Flat - Living room / kitchen

10

FR MX MC FR MX MC FR MX MC FR MX MC FR MX MC B

C

D

0

0

10

FR MX MC FR MX MC FR MX MC FR MX MC FR MX MC A

E

B

scenarios

TM52/59 criterion 1: # Hours exceeding comfort range

TM52 criterion 3: # Hours exceeding absolute limit

TM52/59 criterion 1: # Max exceedable hours

TM52/59 criterion 1: # Max exceedable hours

TM52 criterion 2: Peak daily weighted exceedance (K)

TM52 criterion 2: Peak daily weighted exceedance (K)

Overheating

South Flat - Single bedroom 30

10

FR MX MC FR MX MC FR MX MC FR MX MC FR MX MC B

C

D

20

# hours

# hours

20

30

110

(K)

110

10 0

0

FR MX MC FR MX MC FR MX MC FR MX MC FR MX MC A

E

B

Overheating

South Flat - Double bedroom 1 30

10

FR MX MC FR MX MC FR MX MC FR MX MC FR MX MC D

20

# hours

# hours

20

30

110

(K)

110

C

E

Overheating

North Flat - Double bedroom

B

D

TM52/59 criterion 1: # Hours exceeding comfort range TM59 criterion 2: # Night hours >26°C for bedrooms TM52 criterion 3: # Hours exceeding absolute limit TM52/59 criterion 1: # Max exceedable hours TM59 criterion 2: # Max exceedable night hours for bedrooms TM52 criterion 2: Peak daily weighted exceedance (K)

TM52/59 criterion 1: # Hours exceeding comfort range TM59 criterion 2: # Night hours >26°C for bedrooms TM52 criterion 3: # Hours exceeding absolute limit TM52/59 criterion 1: # Max exceedable hours TM59 criterion 2: # Max exceedable night hours for bedrooms TM52 criterion 2: Peak daily weighted exceedance (K)

A

C

0

scenarios

scenarios

0

E

TM52 criterion 3: # Hours exceeding absolute limit

Overheating

A

D

TM52/59 criterion 1: # Hours exceeding comfort range

North Flat - Single bedroom

0

C

scenarios

0

(K)

A

20 55

10

0

0

(K)

0

# hours

55

30

110

(K)

FR MX MC FR MX MC FR MX MC FR MX MC FR MX MC A

E

B

scenarios

C

scenarios

D

0

E

TM52/59 criterion 1: # Hours exceeding comfort range TM59 criterion 2: # Night hours >26°C for bedrooms TM52 criterion 3: # Hours exceeding absolute limit TM52/59 criterion 1: # Max exceedable hours TM59 criterion 2: # Max exceedable night hours for bedrooms TM52 criterion 2: Peak daily weighted exceedance (K)

TM52/59 criterion 1: # Hours exceeding comfort range TM59 criterion 2: # Night hours >26°C for bedrooms TM52 criterion 3: # Hours exceeding absolute limit TM52/59 criterion 1: # Max exceedable hours TM59 criterion 2: # Max exceedable night hours for bedrooms TM52 criterion 2: Peak daily weighted exceedance (K)

Overheating

South Flat - Double bedroom 2 30

110

# hours

20 10

0

FR MX MC FR MX MC FR MX MC FR MX MC FR MX MC A

B

C

scenarios

D

E

TM52/59 criterion 1: # Hours exceeding comfort range TM59 criterion 2: # Night hours >26°C for bedrooms TM52 criterion 3: # Hours exceeding absolute limit TM52/59 criterion 1: # Max exceedable hours TM59 criterion 2: # Max exceedable night hours for bedrooms TM52 criterion 2: Peak daily weighted exceedance (K)

160

0

(K)

# hours

20

(K)

30

110

Overheating

Overheating

West Flat - Living room / kitchen

East Flat - Living room / kitchen

FR MX MC FR MX MC FR MX MC FR MX MC FR MX MC B

C

D

0

20 55 0

E

10

FR MX MC FR MX MC FR MX MC FR MX MC FR MX MC A

B

scenarios TM52/59 criterion 1: # Hours exceeding comfort range

TM52/59 criterion 1: # Hours exceeding comfort range

TM52 criterion 3: # Hours exceeding absolute limit

TM52 criterion 3: # Hours exceeding absolute limit

TM52/59 criterion 1: # Max exceedable hours

TM52/59 criterion 1: # Max exceedable hours

TM52 criterion 2: Peak daily weighted exceedance (K)

TM52 criterion 2: Peak daily weighted exceedance (K)

Overheating

Overheating

30

C

D

20

# hours

10

FR MX MC FR MX MC FR MX MC FR MX MC FR MX MC

30

110

(K)

# hours

20

B

0

10 0

E

FR MX MC FR MX MC FR MX MC FR MX MC FR MX MC A

B

scenarios

Overheating

Overheating

30

FR MX MC FR MX MC FR MX MC FR MX MC FR MX MC D

E

scenarios TM52/59 criterion 1: # Hours exceeding comfort range TM59 criterion 2: # Night hours >26째C for bedrooms TM52 criterion 3: # Hours exceeding absolute limit TM52/59 criterion 1: # Max exceedable hours TM59 criterion 2: # Max exceedable night hours for bedrooms TM52 criterion 2: Peak daily weighted exceedance (K)

0

20

# hours

10

30

110

(K)

# hours

20

C

E

East Flat - Double bedroom

110

B

D

TM52/59 criterion 1: # Hours exceeding comfort range TM59 criterion 2: # Night hours >26째C for bedrooms TM52 criterion 3: # Hours exceeding absolute limit TM52/59 criterion 1: # Max exceedable hours TM59 criterion 2: # Max exceedable night hours for bedrooms TM52 criterion 2: Peak daily weighted exceedance (K)

West Flat - Double bedroom

A

C

0

scenarios

TM52/59 criterion 1: # Hours exceeding comfort range TM59 criterion 2: # Night hours >26째C for bedrooms TM52 criterion 3: # Hours exceeding absolute limit TM52/59 criterion 1: # Max exceedable hours TM59 criterion 2: # Max exceedable night hours for bedrooms TM52 criterion 2: Peak daily weighted exceedance (K)

0

E

East Flat - Single bedroom

110

A

D

scenarios

West Flat - Single bedroom

0

C

0

(K)

A

# hours

10

10 0

FR MX MC FR MX MC FR MX MC FR MX MC FR MX MC A

B

C

D

0

E

scenarios TM52/59 criterion 1: # Hours exceeding comfort range TM59 criterion 2: # Night hours >26째C for bedrooms TM52 criterion 3: # Hours exceeding absolute limit TM52/59 criterion 1: # Max exceedable hours TM59 criterion 2: # Max exceedable night hours for bedrooms TM52 criterion 2: Peak daily weighted exceedance (K)

161

(K)

0

(K)

# hours

20 55

30

110

(K)

30

110

COURSEWORK COVERSHEET FORM CA1

UNIVERSITY OF WESTMINSTER MARYLEBONE CAMPUS

I confirm that I understand what plagiarism is and have read and understood the section on Assessment Offences in the Essential Information for Students. The work that I have submitted is entirely my own (unless authorised group work). Any work from other authors is duly referenced and acknowledged.

STUDENTS MUST COMPLETE THIS SECTION ONLY IN FULL AND IN CAPITALS Surname Forename PINHEIRO RIBEIRO JULIA Registration No:

1

6

9

9

7

5

2

9

Course

Module Title

THESIS PROJECT

Module Code

Assignment No:

1/1

Date Submitted

Markers:

DR ROSA SCHIANO-PHAN

Word Count

Joint Assignments:

N/A

Joint Submission

ARCHITECTURE AND ENVIRONMENTAL DESIGN 7AEVD005W.2 02

09

18,065

Tutors’ summary comments and feedback to student(s):

All marks are subject to confirmation by the relevant Subject Board

GRADE:

Please be warned that the University employs methods for detecting breaches of the assessment regulations,162 including the use of electronic plagiarism detection software where appropriate.

2019