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Gale & Snowden Presentation to RICS Conference Exeter 2012
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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
www.ecodesign.co.uk
Passivhaus &Design for Future Climate
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
www.ecodesign.co.uk
Knights PlaceAffordable Passive Houses for Exeter
Our Team• Exeter City Council,
Client, Project Manager, Structural and Civil Engineers
• Gale & Snowden Architects, Mechanical Engineers, Landscape Architects
• Jenkins Hansford Partnership - QS
Passivhaus certified
Passive natural vent Permaculture design
Landscape integration
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.
• 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
Knights Place Project Summary
Passivhaus – What is it?
• Voluntary energy standard and a design methodology
• 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
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• How does it compare to ‘the Code’? It doesn’t.
Arctic Station / Samyn & Partner
Passivhaus Refurb / G&S
Rowan House / G&S
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 post-heating (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 insulationUvalue < 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 insulationUvalue < 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 insulationUvalue < 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 DoorsUvalue (instl) < 0.85 W/m²K
Knights Place Exeter - Section
Passivhaus – How does it work?
High levels of insulationUvalue < 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 DoorsUvalue (instl) < 0.85 W/m²K
>75% efficient MVHR(following the PH method)
Knights Place Exeter - Section
Passivhaus – How does it work?
High levels of insulationUvalue < 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 DoorsUvalue (instl) < 0.85 W/m²K
>75% efficient MVHR(following the PH method)
Optimized Solar Orientation
Compact Building FormKnights Place Exeter - Section
Passivhaus – How does it work?
Knights Place Exeter - Section
Energy Losses Energy Gains
Internal Gains
Solar Gains
HeatingVentilation
Losses
Transmission Losses
High levels of insulationUvalue < 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 DoorsUvalue (instl) < 0.85 W/m²K
>75% efficient MVHR(following the PH method)
Optimized Solar Orientation
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 standardsTFA = 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 PlaceReduced running costs
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.
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)
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
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
www.ecodesign.co.uk
St LoyesClimate proof Extra Care for Exeter
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
There is an overwhelming scientific consensus that the climate is changing
We will need to adapt our buildings so that they can cope with
higher temperatures, more extreme weather and changes in rainfall
Design for Future ClimateClimate Change Adaptation Strategy
South West climate change is likely to have the following effects:
• 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
Weather files used: 2030, 2050 & 2080 @ 50 percentile with High CO2 Emission Scenario
MethodologyAnalysis• 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
• User group vulnerability• Increased internal temperatures • Increased external temperatures • Changing rainfall patterns • Localised air pollution
Key
Comfort
Construction
Water Management
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 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 removes 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 onlyOption 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 Landscape 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
Roof GardenCooling effectHealth and WelfareBiodiversity
Adaptation for Heat, Rainfall, and Air pollution,
Green roof 70-200cm substrateSedum, herb, grasses Biodiversity.Reduce peak runoff.Reduce annual runoff by50-60%Cooler surfaces Improve air quality
Deciduous climbers growing up balconieslocal shading
Green microclimate reduce summer temperatures by 3oC
Evaporation / Transpiration
Pleasant shaded spaces for cooling
Permeable paving to allow percolation into soils
Rainwater collectionFor 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 airmicro-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
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
www.ecodesign.co.uk
PassivOffice@ Devonshire Gate, Tiverton
David Disney, Devonshire Gate
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
The Project - RIBA Workstage EFG
Methodology
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 modellingIn IES
Solar XXI Building(Lisbon, Portugal)
Methodology
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.
Climate Risk Radar
Findings - Thermal ComfortSuper insulated envelope
High performance windows
Air tightconstruction
ThermalBridgefree
Inclusion of thermal mass
Externalshading
IntelligentWindow control
ReduceInternalgains
MVHRGroundcooling
Additional measures to reduce the risk of overheating
Supply air reduced by 10°C in summer combined with closing windows above 22-25°C reduces overheating to zero in 2080Th
erm
al m
odel
ling
resu
lts –
Fre
quen
cy o
f ove
rhea
ting
Now 2030 2050 2080
Findings – LandscapeGreen roofAttenuationEvaporation cooling
1. Planting micro climates
2. Resilient landscaping
Transpiration cooling
Reduce hard surfaces next to building
Shading from trees
Shaded external working areas
Ponds to moderate flood/drought cycle
Earth bank and trees act as windbreak
Planted areas to increase infiltration
Root system for erosion control and slope stabilisation
Design for severe weatherDriving rain •robust timber rain screen cladding•enhanced window and door specification and detailingIncreased 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
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
www.ecodesign.co.uk
PassivPoolSwim4Exeter
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
www.ecodesign.co.uk
Passivhaus &Design for Future Climate