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David Gale's presentation at Ecobuild 2013
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architects • engineers
integrated sustainable design
mechanical engineering
natural ventilation design
passivhaus consultancy
healthy building design
landscape design
permaculture design
building monitoring
research & development
Exeter OfficeExeter Bank Chambers67 High StreetExeterDevonEX4 3DTTel. 01392 279220Fax. 01392 279036
Bideford Office18 Market Place
BidefordDevon
EX39 2DR(Registered Office)Tel. 01237 474952Fax. 01237 425669
Climate Ready Design Exeter Extra Care Project
David Gale RIBA
Gale & Snowden Architects & Engineers
e c o b u I l d 2 0 1 3designing for adaptation: considerations for an uncertain future
Our Team
• Exeter City Council, Client, Structural and Civil Engineers
• Gale & Snowden Architects, Mechanical Engineers, Landscape Architects
• Exeter University
• Jenkins HansfordPartnership - QS
Low Energy Design Permaculture Design
Passivhaus Certified Healthy Buildings
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
MethodologyAnalysis• Future climate
• Literature research
• Risk Assessment
• Case studies
• Ongoing IES thermal modelling (Integrated Environmental Solutions)
• PHPP (Passive House Planning Package)
• Integrated team studio working
• Sites assessment
• Climate change adaptation strategies
• Cost benefit analysis
Modelling of building in IES and PHPP
Passivhaus Care
Home, Cologne,
Germany
Design for Future ClimateClimate Change – An Overview
We need to adapt our
buildings to cope with
higher temperatures,
more extreme weather
and changes in rainfall
• Since the 1960s the average temperature in UK has risen
• Average summer temperature increase of 4-6 degree by 2100
predicted for the South West of the UK
• Increase in UV radiation
• Events of extreme rainfall and flooding have become more
frequent and this trend is predicted to increase
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0.6
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Tem
pera
ture
Ch
an
ge
(deg
ree C
)
Change in Average Temperature Since 1850
Design for Future ClimateClimate Change
Building designers typically use weather data that is based on
past experience to predict the future performance of a building.
The building is then
designed to maintain
optimum comfort and
(ideally) to use minimal
energy over the lifetime of
the building.
Ignoring the evidence that
the climate is changing.
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2000 2010 2020 2030 2040 2050 2060 2070 2080 2090 2100
Te
mp
era
ture
Cha
nge
(de
gre
e C
)
We a
re h
ere
.
Typical Design Temperature Range
Design for Future ClimateClimate Change
Building designers typically use weather data that is based on
past experience to predict the future performance of a building.
This project used
probabilistic future
weather data from Exeter
University’s Prometheus
Project which was derived
from the latest climate
projections for the UK
(UKCP09).
The projections are
probabilistic in nature
instead of deterministic so
as to allow users to
assess the level of risk.
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2000 2010 2020 2030 2040 2050 2060 2070 2080 2090 2100
Te
mp
era
ture
Cha
nge
(de
gre
e C
)
We a
re h
ere
.
Typical Design Temperature Range
Predicted Change
in Average Temperature
A Climate Risk Radar was
used to visualise
building’s exposure and to
communicate risks to
clients.
Risks are building type
and project specific.
Risks are rated for their
probability and impact.
Design for Future ClimateAssessing the Risks
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5
10
15
20
25
Potential for mitigation through inclusion of thermal Mass
User group vulnerability -staff/visitors
User group exposure to health hazards
Requirement for maximum internal temperature
User group vulnerability -customers/clients
User group adaptable capacity
Use of building during extreme heat waves
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 loadsMaterial sensitivity to UV exposure
Future finacial viability of energy intensive building type
Sensitivity to UV exposure
Increased seasonal rainfall
Increased storm intensity
Potential mitigation measures in landscape design
Sensitivity to seasonal water shortage
Sensitivity to flooding
Water sensitive landscape requirements
Future finacial viability of high water use building types
Potential for rain/grey water storage
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
Overheating criteria adopted = < 1% of hours above 25°C for
all accommodation
• 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
Design for Future ClimatePHPP Overheating Analysis
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)
h>25°C Classification
>15% catastrophic
10-15% poor
5-10% acceptable
2-5% good
0-2% excellent
Ho
urs
ab
ov
e 2
5 d
eg
C i
n %
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2010 2030 2050 2080
Ho
urs
ab
ov
e 2
5 d
eg
C in
%
4.3 Heavyweight/ no extra shading/ ventilation rate 2 ach
Design for Future ClimatePotential Impact from User Behaviour
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.
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2
4
6
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12
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2010 2030 2050 2080
Ho
urs
ab
ov
e 2
5 d
eg
C in
%
1.3 Heavyweight/ no extra shading/ windows tilted at night (0.3 ach)
4.3 Heavyweight/ no extra shading/ ventilation rate 2 ach
A Heavyweight construction with a ventilation strategy that
achieves an average air change rate of 2 is likely to maintain
good summer comfort until 2080.
If this ventilation strategy is compromised because users do not
operate the building as expected and eg only tilt their windows
at night, then the same building will struggle to maintain good
summer comfort in 2030 and fail already in 2050.
Passive Adaptation 4 Heat1. Passive• Cross ventilation
• Super insulated envelope
• Intelligent ventilation control
• Extracting heat at source
• Mass vs light weight
• Living plants / landscape
• Solar shading
Cross flow vent 10-15% over heating improvement over
single sided ventilation
Overheating Criteria not to exceed 1% occupied hours over 25oC
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
Local shading 2% improvement
Relocation of internal heat gains from
plant outside thermal envelope 5%
improvement
Green microclimate reduce
summer temperatures by 3oC
Evaporation / Transpiration
Green roofPleasant shaded spaces for cooling
Less 1.5oc by microclimate
Active Adaptation 4 Heat2. 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
Early warning temperature system to aid
intelligent window ventilation control
MVHR Activated during heat
waves for minimum fresh air
Windows closed when external air temperatures
are hotter than inside 2-4% reduction
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
Drinking point to aid hydration
Adaptation 4 Air Pollution Healthy design• 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
Plants remove VOCs & CO2
MVHR removes VOCs & CO2
VOCs
CO2
MVHR with pollen filter for affected users
MVHR at night for security on ground floors
Smoke / smog particulates filtered by MVHR
Mosquito insect mesh on opening windows in summer
Pollen
MVHR provides good air quality in bedrooms at night when windows are shut
VOCs
Building and Landscape design working together to provide healthy environments
Courtyard design provides fresh air
microclimate
Adaptation 4 RainfallWater strategies• Water retention via
planting and landscape design
• Irrigation SUDs system
• Rainwater collection
Oversized gutters and downpipes
Wetter winters dryer summers – future rain files need adapting for designers
Rain water harvesting tank on flat roof:
Option A – ground and plants irrigation only
Option B – as A plus flushing WCs, Sluices and laundry
For flushing WCs
For sluice rooms
Storage point at ground level
Water attenuation by rootsRainwater storage crate system =
underground swale irrigation system
Lower collection point for overflow
SUDS / Attenuation system
External area left for rain water harvesting tankRain water harvesting under ground option B
Aquaculture
Integrated LandscapeLandscape
• 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
Roof Garden
Cooling effect
Health and Welfare
Biodiversity
Adaptation for Heat, Rainfall, and Air pollution,
Green roof
70-200cm substrate
Sedum, herb, grasses
Biodiversity.
Reduce peak runoff.
Reduce annual runoff
by50-60%
Cooler surfaces
Improve air qualityDeciduous
climbers
growing up
balconies
local shading
Green microclimate reduce
summer temperatures by 3oC
Evaporation / Transpiration
Pleasant
shaded
spaces for
cooling
Permeable paving to allow percolation
into soils
Rainwater collection
For reuse in garden
areas
Layered structure
to planting,
deciduous canopy
for summer
shading
Sequence of rainwater storage crates for natural
percolation to planting and pumped irrigation
Courtyard fresh air
micro-climate
Internal planting remove
VOC’s and CO2,
Design to allow flooding into
central planting shallow swale
Life Cycle CostingCumulative Energy Related Costs
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.
Life Cycle CostingCumulative 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 CostingCumulative 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
Adaptability of cluster design
• operate clusters together or independently
• division of building functions
• division of ownership
• conversion to dwellings
Opportunities
Simple, low cost measures incorporated at the
beginning of the design process can create robust, low
energy buildings, future proof against climate change
Adoption of Passivhaus standards combines low
energy buildings with excellent summer comfort
An integrated project team applying good practice
building physics is key to enable architecture to perform in
present and future climates
Swim4Exeter
(D4FC 2)
60% Energy reduction and excellent
summer comfort without air
conditioning
Challenges
Lack of guidance
Weather file selection
Compatibility with
current good practice
guidance
Late consideration of
climate change risks
PassivOffices
(D4FC 2)
Low energy use and excellent
summer comfort without air
conditioning
Summary of findings
• Early consideration
• Employ sound building
physics
• Thermal modelling
• Building layout designed
for cross ventilation
• Well insulated & airtight
• Design for microclimates
• Simplicity
Air conditioning can be avoided into 2080 with a passive approach
The Climate Change Adaptation work has directly influenced the
design of the building
Thank You
Swim4Exeter
(D4FC 2)
60% energy reduction and excellent
summer comfort without air
conditioning Exeter Extra Care
(D4FC 1)
Vulnerable user group
Air conditioning could be avoided into
2080 with a passive approach
PassivOffices
(D4FC 2)
Low energy use and excellent
summer comfort without air
conditioning