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Designing A Resilient & Healthy Future

architects • engineers integrated sustainable design mechanical engineering passivhaus designer certified building biology consultant certified landscape architects permaculture certified designer building monitoring & evaluation research & development

David Gale RIBA Gale & Snowden Architects & Engineers

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

three D4FC projects

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


3 D4FC Projects PassivOffices Devonshire Gate (D4FC 2) stage: detailed planning client: David Disney, Devonshire Gate

Swim4Exeter (D4FC 2) stage: feasibility study client: Exeter City Council

Exeter Extra Care (D4FC 1) stage: project commencement client: Exeter City Council


Design for Future Climate climate change data building designers typically use weather data that is based on past experience to predict the future performance of a building !

temperature rise •  lots of data available •  no legal standards for overheating •  some guidance

10

8 7

wind •  no future wind data rain •  no future rain data uv •  no future uv data

6

4 3

we are here

temperature change (degree C)

9

5

what useful information is there for designers?

2 1 typical design temperature range

0 2000 2010 2020 2030 2040 2050 2060 2070 2080 2090 2100

more severe weather events predicted •  frequency unknown •  intensity unknown


Design for Future Climate climate change building designers typically use weather data that is based on past experience to predict the future performance of a building

10

8 7 6 5 4 3

we are here

temperature change (degree C)

9

predicted change In average temperature

probabilistic future weather data from Exeter University’s Prometheus Project, derived from the latest climate projections for the UK (UKCP09) probabilistic in nature instead of deterministic so as to allow users and designers to assess the level of risk

what temperature profiles to use?

2 1 typical design temperature range

0 2000 2010 2020 2030 2040 2050 2060 2070 2080 2090 2100

how long into future? what are the relevant risks?


Communicating Risk! Potential for mitigation through inclusion of thermal Mass User group vulnerability - staff/ Potential for rain/grey water storage 25 visitors Future finacial viability of high water User group exposure to health use building types hazards 20 Water sensitive landscape Requirement for maximum internal requirements temperature 15 User group vulnerability Sensitivity to flooding customers/clients 10 Sensitivity to seasonal water shortage Potential mitigation measures in landscape design

Increased storm intensity

Increased seasonal rainfall Sensitivity to UV exposure Future finacial viability of energy intensive building type Material sensitivity to UV exposure

5 0

User group adaptable capacity

Use of building during extreme heat waves

risks are building type and project specific risks are rated for their probability and impact

Required daylight provison and glazing ratio Mitigation measures in landscape design Potential for mitigation through increased ventilation rate Potential for mitigation through building fabric design Weather exposure/wind loads

2030, 2050 & 2080 @ 50 percentile with high CO2 emission scenario overheating criteria adopted: •  < 1% of hours above 26°C •  < 5% of hours above 25°C

a climate risk radar was used to visualise building’s exposure and to communicate risks to clients

•  user group vulnerability •  increased internal temperatures •  increased external temperatures •  potential changing rainfall patterns •  localised air pollution


Communicating Strategy options

!

hours above 25 deg C in %

overheating analysis - Extra Care

IES dynamic modelling and PHPP were used to assess various ventilation, shading and construction strategies using current and future weather data !

!

overheating classification according to PHI (PB 41)

D4FC modelling used: IES = Integrated Environmental Solutions PHPP = Passivhaus Planning Package CFD = Computational Fluid Dynamics

h>25°C >15% 10-15% 5-10% 2-5% 0-2%

!  !  !  !  !  !

classification catastrophic poor acceptable good excellent


Design for Future Climate potential impact from user behaviour ! 20 20 Hours Hours above above 25 25 deg deg C C in in % %

18 18 16 16 14 14 12 12

1.3 Heavyweight/ no extra shading/ windows tilted at night (0.3 ach)

10 10 88 6 6 4 4 2 2 0 0

4.3 Heavyweight/ no extra shading/ ventilation rate 2 ach

2010 2010

2030 2030

2050 2050

2080 2080

heavyweight construction with ventilation strategy achieving average air change rate of 2 = good summer comfort until 2080 if ventilation strategy is compromised because users do not operate the building as expected (e.g. only tilt their windows at night) then the same building will struggle to maintain good summer comfort in 2030 and fail from 2050

in a Passivhaus night cooling is especially effective and great care needs to be taken not to overestimate achievable ventilation rates studies by the PHI in Germany found that during summer average ventilation rates in cross ventilated flats were between 0.5 and 0.8 ach

be mindful of user behaviour when modelling buildings!


PassivOffice IES dynamic modelling Natural Ventilation Simulations

MVHR, mixed mode, ground cooling simulations

30%

in conjunction with daylight modelling

50%

25%

40%

20%

30%

15%

daylight dimming energy modelling

Current DSY   2030  -­‐  50th   2050  -­‐  50th   Current  DSY  

2030 -­‐  50th  

2050 -­‐  50th  

% of hours > 250C

2080 -­‐  50th  

2080 -­‐  50th  

% of hours > 280C

MVHR 9  

MVHR 8  

MVHR 7  

MVHR 6  

MVHR 5  

MVHR 4  

MVHR 3  

Current DSY  

MVHR 2  

0% 9.  2,  6  &  7  

0%

8. 2  &  6  

10% 1.  base  case     2.  night  cooling     3.  heavy  weight   4.  2  &  3   5.  dimming       6.  low  int.  gains   7.  shading  

5%

MVHR 1  

20%

10%

C

solar gain vs internal gains


Communicating Passive Adaptation Strategies for Heat passive strategies

(assessed via dynamic modelling - IES) Overheating Criteria not to exceed 1% occupied hours over 26oC 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 1% = 87 hours during summer period


Communicating Active Adaptation Strategies for Heat (assessed via dynamic modelling- IES) 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

people centred

management / staff heat stress awareness and training •  drinking points •  no cooking in flats during heat waves •  room ceiling fans

active design •  heat extraction at source •  temperature sensor warning system for vent control •  MVHR coupled with ventilation control •  MVHR ground cooling

1% = 87 hours during summer period 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


Microclimate Adaptation Evaporation / Transpiration

Adaptation for Heat, Rainfall, and Air pollution, 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

•  •  •  •  •  •  •  • 

evapotranspiration courtyard design green roofs minimize hard surfaces shading robust species reduce air pollution water collection / reuse

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

‘external planting could become a viable climate change adaptation strategy for the UK’ - Exeter University

computational fluid dynamic modelling


Future Swim – Exeter building adaptation for water management

standard pool – base case (water use cbm/year) evaporation backwashing

1,451 9,157

refilling/dilution of pool water

8,419

showers wc/urinals

3,368 1,193

calculated annual water use

23,588

proposed water saving strategy

increase relative humidity to 64% provision of tanks and reuse of excess pool water for backwashing

resulting water use (water use cbm/year) 599 0 8,419

use of low water use appliances provision of tanks and reuse of excess pool water for wc/urinals

2,526 0 11,544

analysis indicates that if all of the recommended water saving strategies are implemented the water consumption can be reduced by 50%

water outside •  over-sizing rainwater goods and drainage •  rainwater harvesting •  eliminate flat roofs •  underground attenuation tanks water use •  low water use treatment system •  increased relative humidity to reduce evaporation •  pool backwash storage •  low water use fittings up to 50% water saving possible up to 50% of energy demand of pool buildings can be due to energy losses from evaporation


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 Passivoffice @ Devonshire Gate detail design drawings

•  oversized rainwater goods and drains •  attenuation ponds


Communicating Life Cycle Costs

2050 – upgrade air conditioning system £140,000 - 180,000

2030 - installation of air conditioning system £250,000

cumulative energy related costs

Building Regulations standard building

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

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


Exeter Extra Care Building Future Climate Ready

Life Cycle Costing

2050 - installation of external shading - £80,000

2030 - Installation of thermal monitoring system £10,000

£216,000 additional investment to upgrade to CCA

cumulative energy related costs

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

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


Life Cycle Costing climate change adaptation vs standard building regulations

comparison of cumulative heating and cooling costs: •  CCA Extra Care = £300,000 (zero cooling costs) •  standard Building Regs Extra Care = £2,250,000 + £750,000 = £3,000,000

additional construction investments: •  CCA Extra Care = £300,000 •  standard Building Regulations Extra Care = £430,000 !

payback of additional initial investment after approximately 13 years


Lessons Learnt •  integrate building physics thinking into design process e.g. incorporate thermal modelling as part of normal design methodology

•  early consideration – maximum effect for best cost •  select appropriate future weather data •  limitations - data and modelling tools •  keep it simple – e.g. fabric first, cross ventilation night cooling, thermal mass & incorporate as part of climate change mitigation measures

•  microclimatic design •  user behaviour •  life cycle costs


Future Climate Ready Consultancy

as standard: •  combined architects and m&e services •  integrated Building physics •  PHPP tool for all projects •  PHPP & IES work include future weather data with initial analysis one off consultancy •  IES & PHPP modelling •  risk assessment •  future climate ready design guidance projects incorporating D4FC •  office developments •  science laboratory affordable housing •  multi residential


Thank you

Future Climate Ready Design - Gale & Snowden Architects & Engineers

Designing a Resilient & Healthy Future  

David Gale - Gale & Snowden Architects Ltd. - Design for Future Climate (D4FC) - Technology Strategy Board (TSB)