Gale & Snowden Presentation to RICS Conference Exeter 2012

Page 1

Passivhaus & Design for Future Climate Exeter Office Exeter Bank Chambers 67 High Street Exeter Devon EX4 3DT Tel. 01392 279220 Fax. 01392 279036

Bideford Office 18 Market Place Bideford Devon EX39 2DR (Registered Office) Tel. 01237 474952 Fax. 01237 425669

www.ecodesign.co.uk


Knights Place Affordable Passive Houses for Exeter

Exeter Office Exeter Bank Chambers 67 High Street Exeter Devon EX4 3DT Tel. 01392 279220 Fax. 01392 279036

Bideford Office 18 Market Place Bideford Devon EX39 2DR (Registered Office) Tel. 01237 474952 Fax. 01237 425669

www.ecodesign.co.uk


Our Team • Exeter City Council, Client, Project Manager, Structural and Civil Engineers • Gale & Snowden Architects, Mechanical Engineers, Landscape Architects

Passive natural vent

Passivhaus certified

Permaculture design

Landscape integration

• Jenkins Hansford Partnership - QS


Exeter Infill Sites •12 sites in Exeter •120 affordable units • individual designs •Passivhaus compliant •Minimum CSH 4 •Lifetime Homes compliant Aims to • Provide affordable housing for Exeter • Raise standards of housing in Exeter.


Knights Place Project Summary • • • • •

18 units 15 month construction programme £2.1m development cost £1.15m in HCA grant funding £1,450 /m² Construction Costs

• Project drivers: – – – – – –

fuel poverty energy sustainability future climate change low maintenance downsizing healthy buildings


Passivhaus – What is it? • Voluntary energy standard and a design methodology

Arctic Station / Samyn & Partner

• Suitable for most types of buildings including

dwellings, offices, schools, sports halls, swimming pools, arctic research stations etc.

• Evolved in Germany in the 1990ies • Today more than 35,000 built examples

Passivhaus Refurb / G&S

but only 17 in the UK

• ~1,900 have been certified by the PHI as ‘Quality Approved Passivhaus’

• The Passivhaus Standard can be applied to any climate

Rowan House / G&S

• How does it compare to ‘the Code’? It doesn’t.

Knights Place / G&S


Passivhaus – Certification For the UK, a dwelling is deemed to satisfy the Passivhaus standard if the following criteria are met:

-

Space Heating Demand

<15 kWh/m²/yr

Or Heating Load

<10 W/m²

Primary Energy Demand

<120 kWh/m²/yr

Frequency of Overheating

<10%

Air tightness

<0.6 ac/h@50Pa

All of the above must be verified using the Passive House Planning Package (PHPP) and appropriate regional climatic data – not SAP

PHI functional definition: ‘A Passivhaus is a building, for which thermal comfort can be achieved solely by postheating (or post-cooling) of the fresh air, which is required to maintain sufficient indoor air quality.’ … meaning no other conventional heating system will be required.


Passivhaus – How does it work?

Knights Place Exeter - Section


Passivhaus – How does it work? High levels of insulation

Knights Place Exeter - Section


Passivhaus – How does it work? High levels of insulation Uvalue < 0.15 W/m²K Continuous Air tight Barrier < 0.6 ac/h @ 50 Pa

Knights Place Exeter - Section


Passivhaus – How does it work? High levels of insulation Uvalue < 0.15 W/m²K Continuous Air tight Barrier < 0.6 ac/h @ 50 Pa Thermal Bridge Free (following the PH method)

Knights Place Exeter - Section


Passivhaus – How does it work? High levels of insulation Uvalue < 0.15 W/m²K Continuous Air tight Barrier < 0.6 ac/h @ 50 Pa Thermal Bridge Free (following the PH method) High Performance Windows and Doors Uvalue (instl) < 0.85 W/m²K

Knights Place Exeter - Section


Passivhaus – How does it work? High levels of insulation Uvalue < 0.15 W/m²K Continuous Air tight Barrier < 0.6 ac/h @ 50 Pa Thermal Bridge Free (following the PH method) High Performance Windows and Doors Uvalue (instl) < 0.85 W/m²K >75% efficient MVHR (following the PH method)

Knights Place Exeter - Section


Passivhaus – How does it work? High levels of insulation Uvalue < 0.15 W/m²K Continuous Air tight Barrier < 0.6 ac/h @ 50 Pa Thermal Bridge Free (following the PH method) High Performance Windows and Doors Uvalue (instl) < 0.85 W/m²K >75% efficient MVHR (following the PH method) Optimized Solar Orientation Knights Place Exeter - Section

Compact Building Form


Passivhaus – How does it work? Energy Losses

Energy Gains

High levels of insulation Uvalue < 0.15 W/m²K Continuous Air tight Barrier < 0.6 ac/h @ 50 Pa

Transmission Losses

Internal Gains Solar Gains

Ventilation Losses

Heating

Thermal Bridge Free (following the PH method) High Performance Windows and Doors Uvalue (instl) < 0.85 W/m²K >75% efficient MVHR (following the PH method) Optimized Solar Orientation

Knights Place Exeter - Section

Compact Building Form


Passivhaus – Why bother? Minimal Energy Losses

Thermal Imaging of Knights Place proves: Implementing the Passivhaus methodology has reduced heat losses and thermal bridging to a minimum.


Passivhaus – Why bother? How does it compare to a standard build?

The holistic design strategy allows for energy savings of up to 75%, making these units truly affordable and protecting future tenants from fuel poverty.

TER = SAP ‘Target Energy Emission Rate’ if building had been built to 2006 Building Regs standards TFA = Treated Floor Area


Passivhaus – Why bother? How does it compare to a standard build?

G&S received Government funding through the TSB to monitor the energy performance of Rowan House and Knights Place. The average space heating demand for Rowan House in 2011 came out at 12 kWh/m²/year


Knights Place Reduced running costs Comparison of Energy Costs - EPC | PHPP | UK Standard EPC (flat 5)

Passivhaus Planning Package

Approx UK Standard

units

Primary Energy Use

73

114

165-250

(kWh/m2/year)

Heating Demand

2

12

60-90

(kWh/m2/year)

CO₂emissions

0.6

0.9

2.5

(tonnes per year)

Lighting

£24

£9

£45

(per year)

Heating

£18

£95

£450-500

(per year)

Hot water

£86

£150

£230

(per year)

On average energy prices in the past 10 years have increased by approximately 10% per annum. With current trends in energy and fossil fuels it is not likely that this will change over the next 10 years. Assuming a 10% increase per annum, £800 today (typical heating and hot water cost per annum of an existing flat) would be in 5 years time = £1171, in 10 years time £1, 715 The project has recently received funding from TSB to monitor energy and building use.


Healthy Buildings Building Biology Principles

• Non-toxic eg: non VOC materials • High quality ventilation • High levels of natural daylight • Thermal comfort • Avoidance of dust mites by good design and materials selection • User control • Radial wiring to reduce low frequency Electro-Magnetic Fields (EMFs) • Non PVC materials specified


Landscaping

Permaculture principles Landscape Architect and Species expert as part of Gale & Snowden in-house design team. Emphasis on integrated design using Permaculture principles Working with natural system not against


St Loyes Climate proof Extra Care for Exeter

Exeter Office Exeter Bank Chambers 67 High Street Exeter Devon EX4 3DT Tel. 01392 279220 Fax. 01392 279036

Bideford Office 18 Market Place Bideford Devon EX39 2DR (Registered Office) Tel. 01237 474952 Fax. 01237 425669

www.ecodesign.co.uk


Project Starting Point • New build 50 flats and communal facilities • Restrictive site • Shading of external courtyard space making it unusable • Institutional building with central corridor • Natural cross ventilation not possible

Shading diagram June 21st 18.00


Design for Future Climate Climate Change Adaptation Strategy Weather files used: 2030, 2050 & 2080 @ 50 percentile with High CO2 Emission Scenario South West climate change is likely to have the following effects:

There is an overwhelming scientific consensus that the climate is changing

• average temperatures in the south west are expected to rise by 4-6 degrees over the next 80 years

• average solar radiation is expected to increase significantly, increasing the exposure to UV

• increase in exposure to pollen and higher ozone levels • wind loads and storm intensity are likely to increase • 50% reduced rainfall in summer with longer periods of drought and

• 50% increased rainfall in winter

We will need to adapt our buildings so that they can cope with higher temperatures, more extreme weather and changes in rainfall


Analysis

Methodology

• Literature research • Case studies • Thermal modelling past projects with future weather files • Risk Assessment • Ongoing IES thermal modelling at early design stages • PHPP (Passive House Planning Package) • Fluid dynamics analysis • Occupant heat stress analysis • Cost matrix • Integrated team studio working

2030, 2050 & 2080 @ 50 percentile with high CO2 emission scenario


Future Climate Change Risk Assessment Key Comfort Construction Water Management

• • • • •

User group vulnerability Increased internal temperatures Increased external temperatures Changing rainfall patterns Localised air pollution


Climate Change Adaptation Design • High levels of Dementia care • Cluster design • Usable soft-centre courtyard • Connection to others • Community and privacy

low energy - healthy - integrated landscape – non institutional


Passive Adaptation 4 Heat 1. Passive

Overheating Criteria not to exceed 1% occupied hours over 25 oC

• •

Cross flow vent 10-15% over heating improvement over single sided ventilation

Super-insulated, air tight envelope helps to stabilise internal temperatures and reduce solar gain penetration 3 – 6% improvement

• •

Intelligent window control 4% improvement Mass vs light weight 2-4% improvement with mass Less 1.5oc by microclimate

Local shading 2% improvement

• •

Evaporation / Transpiration

Pleasant shaded spaces for cooling Relocation of internal heat gains from plant outside thermal envelope 5% improvement

Green microclimate reduce summer temperatures by 3oC

Green roof

Cross ventilation Super insulated envelope Intelligent ventilation control Extracting heat at source Mass vs light weight Living plants / landscape Solar shading


Active Adaptation 4 Heat MVHR Activated during heat waves for minimum fresh air

Windows closed when external air temperatures are hotter than inside 2-4% reduction

Early warning temperature system to aid intelligent window ventilation control Drinking point to aid hydration

Ceiling mounted fans increase air movement and sweat evaporation

Heat extract at source

Supply air reduced by 10oC in summer combined with closing windows above 22-25oC reduces overheating to zero 2080

Close loop ground to brine heat exchanger

2. People centred

• Management / staff heat stress awareness and training • Drinking points • No cooking in flats during heat waves • Room ceiling fans

3. Active design • Heat extraction at source • Temperature sensor warning system for vent control • MVHR coupled with ventilation control • MVHR ground cooling


Adaptation 4 Air Pollution

Healthy design • • •

MVHR provides good air quality in bedrooms at night when windows are shut

• VOCs

Plants removes VOCs & CO2 MVHR removes VOCs & CO2

VOCs

Courtyard design provides fresh air microclimate

• • •

MVHR with pollen filter for affected users CO2

Smoke / smog particulates filtered by MVHR

• Pollen

Mosquito insect mesh on opening windows in summer MVHR at night for security on ground floors Building and Landscape design working together to provide healthy environments

Good ventilation rates Thermal comfort Filtration of pollutants and pollen using MVHR when needed Removal of CO2 by MVHR Non-VOC materials Plants used to help clean air Cleanable surfaces to reduce dust mites infestation Radial wiring to reduce EMFs


Adaptation 4 Rainfall Rain water harvesting tank on flat roof: Option A – ground and plants irrigation only Option B – as A plus flushing WCs, Sluices and laundry

Oversized gutters and downpipes

Water strategies • • •

For flushing WCs

Water retention via planting and landscape design Irrigation SUDs system Rainwater collection

SUDS / Attenuation system

For sluice rooms

Storage point at ground level Rain water harvesting under ground option B External area left for rain water harvesting tank

Water attenuation by roots Rainwater storage crate system = underground swale irrigation system Lower collection point for overflow

Wetter winters dryer summers – future rain files need adapting for designers

Aquaculture


Integrated Landscape Adaptation for Heat, Rainfall, and Air pollution,

Evaporation / Transpiration

Roof Garden Cooling effect Health and Welfare Biodiversity Rainwater collection For reuse in garden areas Deciduous climbers growing up balconies local shading Courtyard fresh air micro-climate Internal planting remove VOC’s and CO2,

Permeable paving to allow percolation into soils Sequence of rainwater storage crates for natural percolation to planting and pumped irrigation

Layered structure to planting, deciduous canopy for summer shading

Green roof 70-200cm substrate Sedum, herb, grasses Biodiversity. Reduce peak runoff. Reduce annual runoff by50-60% Cooler surfaces Improve air quality

• • • • •

• Pleasant shaded spaces for cooling Design to allow flooding into central planting shallow swale Green microclimate reduce summer temperatures by 3oC

Landscape Thermal comfort - cooling, shading Water - collection and reuse Biodiversity Health & well being Plants choice - species suited to challenging conditions, winds, drought, occasional flooding Minimise hard surfacing


Life Cycle Costing Cumulative Energy Related Costs

All costs have been discounted at 5% to represent present value. An annual increase in fuel costs of 4% has been allowed for and a reduction of heating demand of 30% from 2050 to 2080 has been included .

Cumulative energy costs for an Extra Care facility, built to 2010 Building Regulation requirements, for heating, cooling and additional future investments required to maintain adequate comfort conditions over the lifetime of the building.


Life Cycle Costing Cumulative Energy Related Costs

All costs have been discounted at 5% to represent present value. An annual increase in fuel costs of 4% has been allowed for and a reduction of heating demand of 30% from 2050 to 2080 has been included.

Cumulative energy costs for an Extra Care facility, built to Passivhaus Standard, for heating, cooling and additional future investments required to maintain adequate comfort conditions over the lifetime of the building.


Life Cycle Costing Cumulative Energy Related Costs

Comparison of Cumulative Energy costs: Payback of additional initial investment after approx. 13 years

All costs have been discounted at 5% to represent present value. An annual increase in fuel costs of 4% has been allowed for and a reduction of heating demand of 30% from 2050 to 2080 has been included.


South Elevation

North Elevation



PassivOffice @ Devonshire Gate, Tiverton

David Disney, Devonshire Gate

Exeter Office Exeter Bank Chambers 67 High Street Exeter Devon EX4 3DT Tel. 01392 279220 Fax. 01392 279036

Bideford Office 18 Market Place Bideford Devon EX39 2DR (Registered Office) Tel. 01237 474952 Fax. 01237 425669

www.ecodesign.co.uk


The Project

- RIBA Workstage EFG

New Office Project • • • •

First Phase 1250 sqm Passivhaus design Natural ventilation in summer • Optimum day light • Planning restrictions • RIBA Workstage E/F/G Low energy - Healthy - Integrated landscape


Methodology Solar XXI Building (Lisbon, Portugal)

Analysis

• Literature research • Case studies • Thermal modelling past projects with future weather files • Ongoing IES thermal modelling • PHPP (Passive House Planning Package) • Occupant heat stress & impact on productivity analysis • Cost matrix • Integrated team studio working Day light modelling In IES


Methodology Climate Risk Radar

Climate change related risks are rated for their probability and their potential impact resulting in a risk magnitude.

Following detailed analysis of building’s exposure to climate change related risks, the 2030, 2050 & 2080 @ 50 percentile with high CO2 emission scenario was chosen.


Air tight construction

Super Thermal insulated Bridge envelope free

High performance windows

Thermal modelling results – Frequency of overheating

Findings - Thermal Comfort

Additional measures to reduce the risk of overheating

External shading

MVHR Ground cooling

Inclusion Reduce of thermal Internal mass gains

Intelligent Window control

Supply air reduced by 10°C in summer combined with closing windows above 22-25°C reduces overheating to zero in 2080 Now 2030 2050 2080


Findings – Landscape Shaded external working areas

Shading from trees

Reduce hard surfaces next to building

Green roof Attenuation Evaporation cooling

Transpiration cooling

1. Planting micro climates 2. Resilient landscaping

Ponds to moderate flood/drought cycle

Root system for erosion control and slope stabilisation

Earth bank Planted areas and trees act to increase as windbreak infiltration


Design for severe weather Driving rain •robust timber rain screen cladding •enhanced window and door specification and detailing

Increased wind severity

•eaves and verge robust details •Robust materials and secure fixings

Increased UV •turf roof •timber cladding

Future adaptability •future addition for shading devices •Future external working areas

Flooding events

•oversized rainwater goods and drains •attenuation ponds

Passivoffice @ Devonshire Gate detail design drawings


PassivPool Swim4Exeter

Exeter Office Exeter Bank Chambers 67 High Street Exeter Devon EX4 3DT Tel. 01392 279220 Fax. 01392 279036

Bideford Office 18 Market Place Bideford Devon EX39 2DR (Registered Office) Tel. 01237 474952 Fax. 01237 425669

www.ecodesign.co.uk



Passivhaus & Design for Future Climate Exeter Office Exeter Bank Chambers 67 High Street Exeter Devon EX4 3DT Tel. 01392 279220 Fax. 01392 279036

Bideford Office 18 Market Place Bideford Devon EX39 2DR (Registered Office) Tel. 01237 474952 Fax. 01237 425669

www.ecodesign.co.uk


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