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