Renovation of multifamily houses in Sweden Åsa Wahlström CIT Energy Management
Energy use in the sector of apartment blocks Total energy use in Sweden 410 TWh yearly The built environment use 160 TWh yearly In apartment blocks 42 TWh yearly (25% of all buildings) Heating and production of hot water: 28 TWh Operation and domestic electricity: 14 TWh
Other Natural gas Electricity Oil District heating Year of construction
Number of apartments 800000 700000 600000 500000 400000 300000 200000 100000 0 Other Sluten kvartersbebyggelse och övriga flerbostadshus Slab block Lamellhus Punkthus Tower blocks Houses with external galleries Loftgångshus Small apartment buildings Flerbostadsvillor m.m. Year of construction Källa: Så byggdes husen 1880-2000, femte upplagan. C. Björk, P. Kallstenius & L. Reppen (2003)
National target for the building sector 20 % until 2020 50 % until 2050 kwh/m 2 Specific district heating use 200 180 160 140 120 100 80 60 40 20 0 1996 1998 2000 2002 2004 2006 2008 2010 Year Actual energy use Normal year correction
Recast of the European Energy Performance of Building Directive Member states should state energy performance requirements for: nearly zero-energy buildings (nzeb) for new constructions public buildings 2019 all buildings 2021 minimum requirements when buildings undergo a major renovation to the extent that this is technically, functionally and economically feasible
1 January 2013 Reconstruction requirements in the building regulations The basis for quality requirements that should be applied during major renovation are the same as the ones at new construction
New construction requirements in 2013 Building Yearly energy use for heating, comfort cooling, domestic hot water, and electricity for operation of the building s services systems. (kwh/m 2 ) Climate zon I II III Residential buildings with heating systems other than electric heating Residential buildings with electric heating 130 110 90 95 75 55
Heating system requirements climate zone 3 (kwh/m 2 ) Keep district heating 90 Install ground source heat pump Install air to water heat pump Exhaust air heat pump (max 10 W/m 2 ) 55 55 90
Measures Heat recovery - Install air to air heat exchanger - Install exhaust air heat pump Measures addressing domestic hot water provision Measures addressing electricity use for shared services in the building Loft insulation Window replacement Facade insulation Installation of solar energy
Present value of life cycle cost [kr/m 2 ] Example of Low-rise apartment buildings climate zone III, Built 1950-1960 3000 2900 2800 BBR requirements District heating 2700 2600 2500 2400 2300 2200 Ground source heat pump Air to water heat pump 2100 2000 0 50 100 150 Energy use [kwh/m 2 year] Exhaust air heat pump
Present value of life cycle cost [kr/m 2 ] Example of Low-rise apartment buildings climate zone III, Built 1950-1960 3000 2900 2800 2700 2600 2500 2400 2300 2200 2100 2000 BBR requirements Facade insulation Window replacement 0 50 100 150 Energy use [kwh/m 2 year] District heating Ground source heat pump Air to water heat pump Exhaust air heat pump
Present value of life cycle cost [kr/m 2 ] Example of Low-rise apartment buildings climate zone III, Built 1950-1960 3000 2900 2800 BBR requirements District heating 2700 2600 2500 2400 2300 2200 Ground source heat pump Air to water heat pump 2100 2000 Heat recovery 0 50 100 150 Energy use [kwh/m 2 year] Exhaust air heat pump
Present value of life cycle cost [kr/m 2 ] Example of Low-rise apartment buildings climate zone III, Built 1950-1960 3000 2900 2800 BBR requirements District heating 2700 2600 2500 2400 2300 2200 Ground source heat pump Air to water heat pump 2100 2000 Hot Water Measures 0 50 100 150 Energy use [kwh/m 2 year] Exhaust air heat pump
Heat recovery of exhaust air Innovation procurement 2010 2013
Objectives Introduce companies on the market that offers complete system solutions Development and costs reduction Improve operation experiences (installation, service and maintenance) Show the energy saving potential
Group of clients
Main requirements Energy efficiency Costs Indoor environment Design and function Installation Operation and maintenance
Innovation procurement Stage 1: Procurement of systems to demonstration buildings according to requirement specification Stage 2: Installation and evaluation in demonstration buildings. One year of measurements. Improvement of requirement specification. Stage 3: Continuation of public procurement (general agreement) according to the new requirement specification of buildings
Heat recovery with air to air heat exchanger
Duct systems in the apartments Design and function
Exhaust air heat pump Outdoor heat pump with improved efficiency by a condenser
Hur hittar man utrymmen?
Hur hittar man utrymmen?
Original exhaust brick duct
Improved indoor climate Make the building envelope tight Air to air heat exchanger : preheated supply air Exhaust air heat pump: supply air behind radiators
Examples of typical energy savings Heat recovery with air to air heat exchanger Exhaust air heat pump > 10 W/m²A temp Increase of electricity: 2-6 kwh/ m²a temp Decrease of district heating: 30-35 kwh/ m²a temp Increase of electricity: 47 kwh/ m²a temp Decrease of district heating: 135 kwh/ m²a temp
Rational facade renovation Innovation procurement 2010 Terminated 2011 Development project
Prefabricated facade elements in concrete and additional insulation
Profile system elements in aluminium and steel
Both at same time.. Additional insulation with rendering and ventilation ducts within the insulation. Supply air below windows and heat recovery unit on the attic.
Backa Röd: A shining example
Built 1971 1357 m 2 Source: Bostad AB Poseidon 4 floors 16 apartments 3 room and kitchen of 80 m 2
U-values (W/m 2 K) Measures building envelope External wall 0.12 (0.31) Windows 0.9 (2.4) Attic floor 0.1 (0.14) Foundation 0.3 (0.48) Floor over crawl space 0.1 (0.4) Air tightness 0.13 (1.17) (l/s m 2 ) Source: Bostad AB Poseidon
Measures ventilation Heat recovery with air to air heat exchanger Central rotating exchanger New fan room Kitchen ventilation: Cooker fan separately exhaust vent Heating: Radiators with district heating Source: Bostad AB Poseidon
Measures Heat recovery Roof insulation Foundation New windows Facade insulation External wall Elecytricity use + 1.7 kwh/m 2 District heating before District heating after New balkonies
Energy use Before renov. After renov. District heating 170 kwh/m 2 54 kwh/m 2 of which heating 133 kwh/m 2 25 kwh/m 2 hot water 32 kwh/m 2 25 kwh/m 2 culvert losses 5 kwh/m 2 4 kwh/m 2 Electricity (exkl domestic) 8 kwh/m 2 6 kwh/m 2 Totalt 178 kwh/m 2 (A temp ) 60 kwh/m 2 (A tep ) Source: Bostad AB Poseidon
Economical evaluation Renovation with energy efficiency measures requires extra costs of about 27 000 Euro per apartment Renovation result in decreased energy costs of about 755 Euro/year and apartment After renovation the rent for 3RoK are 695 Euro/month A rent of 755 Euro/month would have paid for the energy measures In next project an additional floor is added in order to get extra rent incomes.
We only get one chance to do this right
Thanks!