Passivhaus monitoring
Dr. Paola Sassi Programme leader MSc Sustainable Building: Performance and Design Department of Architecture, Oxford Brookes University Sassi Chamberlain Architects
THE BUILDING DESIGN AND CONSTRUCTION
Mezzanine
Ground floor
First floor
North Elevation
South Elevation
Achieving low energy buildings PRINCIPLES FOR LOW ENERGY DESIGN
APPROACH ADOPTED BY PASSIVHAUS
Step 1 – reduce energy requirements through passive and fabric design
• Well insulated building fabric - Compact and well insulated building envelope with U-value of less than 0.14 W/m²K AND Uvalues of windows including glass and frame not to exceed 0.8 W/ m²K AND minimise cold bridging •
Airtight structure - maximum 0.6 air changes per hour
• Passive solar heating - South orientation of living spaces with maximum glazing on south side of building and minimal overshadowing
Step 2 – provide services through efficient means
Step 3 – provide energy from low / zero CO2 energy sources
• Ventilation with heat recovery of stale air. Mechanical ventilation with heat recovery with over 80% efficiency. Passive pre-heating of fresh air entering the building, possibly through a earth ducts •
Appliances to be energy efficient
•
Adopt renewable energy sources if possible
Step 1 reduce energy requirements through passive and fabric design
Minimise heat loss and gains with insulation Wall & roof construction U-value 0.13W/sqmK •
Ply finish to walls
•
Plasterboard for fire protection
•
100mm service void insulated with hemp
•
Vapour control layer
•
200mm structural frame insulated with hemp
•
80mm timber fibre insulation
•
Render/ timber cladding finish
Minimising heat loss by minimising cold bridges
Inward opening windows with min. 50mm insulation covering the frame externally
Minimising heat loss by minimising infiltration losses
Maximising solar gains
South elevation
North elevation
Orientation and insulation
U-value windows 0.7W/m²K
Transmission Losses
kWh/a
0
709 0
152 1068 207
U-value windows 1.6W/m²K
Heat Gains Solar Radiation
kWh/a
0
1334
64 98
0
1496
Transmission Losses
1933 0
kWh/a
1937
152 2604 518
kWh/a
0
Heat Gains Solar Radiation 0 0
98 2139 104
Step 2 provide services through efficient means
Mechanical ventilation with heat recovery (92%)
energy efficient appliances and lighting
Step 3 provide energy from low and zero CO2 energy sources
Solar thermal panels and photovoltaics (1.25kWp)
2993 546 864 1583
CO2 kg/a without renewables CO2 kg/a savings from PVs CO2 kg/a savings from solar thermal CO2 kg/a with renewables
BUILDING ASSESSMENT AND POST OCCUPANCY BUILDING MONITORING
Aim: establish what design and construction contributes to minimising human impacts on the planet
Questions Has the building achieved the Passivhaus targets? • Maximum heating requirements of 15 kWh/m²a • Maximum air changes per hour 0.6 • Maximum total primary energy requirements of 120 kWh/m²a Does it represent a minimal impact dwelling? • Energy consumption: maximum 120 kWh/m²a primary energy • Water consumption: maximum 80 ltrs per person per day • Material use and waste: max. non-closed loop materials 80kg/m² • Satisfactorily provides a healthy and comfortable environment Does it enable a low impact lifestyle? • Ecological Footprint
Has the building achieved the Passivhaus targets? Airtightness test ground floor flat • 1.8 m³/m² = 2.7air changes/hr
first floor flat • 1.3 m³/m² = 1.7air changes/hr
Does it represent a minimal impact dwelling?
• • • •
Energy consumption: maximum 120 kWh/m²a primary energy Water consumption: maximum 80 ltrs per person per day Material use and waste: max. non-closed loop materials 80kg/m² Satisfactorily provides a healthy and comfortable environment Flats
Modelled primary energy consumption (PHPP)
Monitored energy consumption over 2 years
Ground floor
101 kWh/m²a
109 kWh/m²a
First floor
93 kWh/m²a
37 kWh/m²a
Does it represent a minimal impact dwelling?
• • • •
Energy consumption: maximum 120 kWh/m²a primary energy Water consumption: maximum 80 ltrs per person per day Material use and waste: max. non-closed loop materials 80kg/m² Satisfactorily provides a healthy and comfortable environment
Create a healthy living environment
Design for closed loop material cycles
•
•
Most materials can be either composted or recycled
•
Most building elements can be dismantled
•
•
All materials are associated with minimal off-gassing of formaldehyde and other volatile organic compounds Hygroscopic materials (hemp and timber) help balance the humidity of the building Ample natural light provided throughout
Minimal water use •
Low water use sanitary ware
•
Rainwater for garden use
Does it represent a minimal impact dwelling?
• • • •
Energy consumption: maximum 120 kWh/m²a primary energy Water consumption: maximum 80 ltrs per person per day Material use and waste: max. non-closed loop materials 80kg/m² Satisfactorily provides a healthy and comfortable environment
Mezzanine
Ground floor
First floor
North Elevation
South Elevation
Occupant interviews
• • • •
• •
• • • •
L: Do you feel that your standard of living has changed since you have been living here? You can deal with cooler weather more because of living here? Y: No, not at all, I don’t think it has affected my standard of living at all. L: You would still put on a heat if you were cold? Y: Yea, you become more aware if you like. You start thinking, OK if I have this light on then any sort of energy that I might have generated, I might have created goes out the window because I have a light that shouldn’t be on, so yes you do become aware of things but then you have guests and they have no idea. You’re like, don’t put the onion in that bin, and put it in that one! L: Do you feel you are quite aware of energy usage and that you’re self chose this house because of that? Y: I chose this house because every other house I was shown was the same. It was the most interesting house that I was shown, I think I saw all of Cardiff when I came here, and then of course everything was explained. But it wasn’t on that basis L: Once you lived here you became more aware of it? Y: Yea L: Do you feel you appreciate different things? Y: Yea, the estate agent even said ‘So now we’re going to a weird place’-I responded ‘yes! Let’s go to this weird place!’
Energy consumption and costs
Flats
Monitored energy consumption over 2 years
Energy costs including standing charges per year
Energy costs per sq m including standing charges per year
Ground floor
109 kWh/m²a
£300
£6.63
First floor
37 kWh/m²a
£140
£2.46
ratio of flats
1:3
1:2.7
Improvements and lessons learnt Building design • Hot water cylinder position • Rooflight orientation • Fuel source • MVHR User impact • educating over and over • assumptions about comfort
energy to CO2 emissions Grid electricity 0.537 kg CO2/kWh Natural gas
0.185 kg CO2/kWh
LPG
0.214 kg CO2/kWh
Wood pellets
0.025 kg CO2/kWh
Carbon dioxide emission: further reductions
Alternative hot water and heating from gas
2492 546 864 1082
CO2 kg/a without renewables
Existing hot water and heating electric
2993
CO2 kg/a savings from PVs CO2 kg/a savings from solar thermal
546
CO2 kg/a with renewables
1583
864
CO2 kg/a without renewables CO2 kg/a savings from PVs CO2 kg/a savings from solar thermal CO2 kg/a with renewables
Improvements and lessons learnt Building design • Hot water cylinder position • Rooflight orientation • Fuel source • MVHR User impact • educating over and over • assumptions about comfort
Does it represent a minimal impact dwelling? • Energy consumption: maximum 120 kWh/m²a primary energy • Water consumption: maximum 80 ltrs per person per day • Material use and waste: max. non-closed loop materials 80kg/m² • Satisfactorily provides a healthy and comfortable environment Does it enable a low impact lifestyle? • Ecological Footprint
CO2 emissions from buildings and activities Typical levels of CO2 generation by the average family
Tonnes of CO2 /yr
New house built to modern Building Regulations
4.5
Older house pre 1960
10
Family car use
4.5
Family holiday to the Mediterranean
2.5
Family food
4
Does it enable a low impact lifestyle? Ecological Footprint
work shops park station farmer’s market station
Calculation of ecological footprint www.myfootprint.org
There are only 15.71 global hectares available per person on a renewable basis.
Questions Has the building achieved the Passivhaus targets? • Maximum heating requirements of 15 kWh/m²a • Maximum air changes per hour 0.6 • Maximum total primary energy requirements of 120 kWh/m²a Does it represent a minimal impact dwelling? • Energy consumption: maximum 120 kWh/m²a primary energy • Water consumption: maximum 80 ltrs per person per day • Material use and waste: max. non-closed loop materials 80kg/m² • Satisfactorily provides a healthy and comfortable environment Does it enable a low impact lifestyle? • Ecological Footprint IS IT FEASIBLE?
Energy efficient versus Ecological: cost comparison additional cost compared to base
Bld Regs equivalent - Option 1 (base) total paid Yearly mortgage payments (6.45% interest repayment mortgage for 25 years) Yearly energy costs based on PHPP yearly mortgage payments + energy running costs
percentage increase on base
£168,303.08 £13,572.00 £1,656.26 £15,228.26
NON-energy efficient and NON-eco - Option 2 total paid 2 - yearly mortgage payments (6.45% interest repayment mortgage for 25 years) 2 - Yearly energy costs yearly mortgage payments + energy running costs
£169,232.40
£929.31
0.6%
£13,644.00 £1,262.17 £14,906.17
Energy efficient but NON-eco - Option 3 total paid 3 - yearly mortgage payments (6.45% interest repayment mortgage for 25 yrs) 3 - Yearly energy costs
£192,751.25
£24,448.17
14.5%
£30,787.34
18.3%
£15,540.00 £336.87
yearly mortgage payments + energy running costs
£15,876.87
Yearly mortgage payments (5.45% interest repayment mortgage for 25 years)
£14,124.00
yearly mortgage payments (5.45) + energy running costs
£14,460.87
Built option - energy efficient AND eco - Option 4 total paid 4 - yearly mortgage payments (6.45% interest repayment mortgage for 25 yrs) 4 - Yearly energy costs
£199,090.43 £16,056.00 £336.87
yearly mortgage payments + energy running costs
£16,392.87
Yearly mortgage payments (5.45% interest repayment mortgage for 25 years)
£14,592.00
yearly mortgage payments (5.45) + energy running costs
£14,928.87
Energy efficient versus Ecological: cost comparison
Thank you