áååçî~íáîé=äìáäçáåöë Klosterenga Oslo, Norway Important Facts Owner Boligbyggelag USBL, a co-operative housing association. Design Team Architects: Gasa Architects AS and Architekskap AS HVAC: Erichsen & Horgen AS Solar System: SolarNor AS Summary Klosterenga, a 35-unit residential apartment building located in Oslo, Norway, demonstrates how well-thought-out building design coupled with a wide range of energy-and water-conserving features can reduce energy and water use. With a high thermal mass and a combination active/passive solar system, Klosterenga uses less energy than a building of a comparable size and also includes on-site greywater purification, radiant flooring and water-conserving fixtures. 1 Environmental and Sustainability Profile for Oslo 2003. 2 Klosterenga Ecological Housing. http://www2.arkitektur.no/page/ecoark_detalj/ecoark_prosjekter_energi/10056/57484.html 3 European Green Building Forum. Catalogue of Best Practice Examples. April 2001. http://www.egbf.org/pdfs/klosterenga.pdf Centre for Analysis and Dissemination of Demonstrated Energy Technologies (CADDET). Technical Brochure No. 170. Housing Co-Operative with an Ecological Profile. http://www.caddet.org/public/uploads/pdfs/brochure/no170.pdf 4 According to CMHC s Household Guide to Water Efficiency (2000), average daily water consumption in Canada is approximately 326 litres per person, or 118,990 litres per person per year. Site area 1,300 m 2 (13,993 sq. ft.) (each unit 75 m 2 [807 sq. ft.]) Energy Sources Heating: The building is oriented east-west for optimal solar radiation. The southern facade includes a double-glazed buffer zone for passive solar heat gain and for preheating of ventilation air. The rooftop solar hot water system provides all of the energy required for space heating and for domestic hot water use. Electricity: Most (99.3%) of Oslo s electricity is generated by hydropower; during cold periods when hydropower is in shorter supply, however, electricity is imported from abroad 1. Building Costs / Financing Building Costs: Total Cost $5M Cdn ($3,887 Cdn/m 2 ) 2. This is approximately 15%-20% higher than the reference building at a nearby site 3, with paybacks for individual building components ranging from 15 20 years. Financing: The project was supported by the European Commission s European Housing Ecology Network, the Housing Bank of Norway, the Research Council of Norway, the City of Oslo, E-CO Smart Norway and the Norwegian Water Resources and Energy Directorate. Energy Goals 104 kwh/m 2 annual energy consumption. Average consumption after one year was 127 kwh/m 2. 4 Status Planning began at the end of 1995 and the project was completed in 1999-2000.
Background Boligbyggelag USBL (USBL), a co-operative housing association established in 1948, began building the Klosterenga eco-housing development in 1999 as part of an urban housing revitalization project launched by the City of Oslo. USBL manages approximately 170 housing co-operatives. Klosterenga is situated in one of the oldest parts of Oslo an area known as Gamlebyen (Old Town). Remnants of Viking settlements dating back to AD 900 can still be found in the area. For many years, Old Town suffered from many of the common inner-city problems associated with urban centres, such as noise pollution and poor air quality due to heavy traffic. The city therefore decided to launch a renewal project during the mid-1980s to renovate older buildings for better energy efficiency and to reduce the amount of car and railway traffic and pollution. The Klosterenga building was a former greyfield site and planning for the building began in 1995. The design team had several goals: Achieve an annual energy consumption of 104 kwh/m 2. Use life cycle cost analysis when selecting construction materials and methods. Have limited environmental impact during and after construction. Increase the extent and quality of the natural area on the site. In addition to the support received by the organizations listed above, Klosterenga also received support from the European Union s SHINE program (Solar Housing through Innovation from the Natural Environment). Design Process/ Construction Materials Together with USBL, three other organizations were involved in the design process: Gasa Architects AS and Arkitekskap AS (architectural firms), and SolarNor AS (solar system supplier). The design team used well-known and established technology and all components used were already available in the marketplace. Subcontractors were not as familiar with solar energy systems The interior courtyard is protected from wind, traffic noise and pollution. Photo courtesy of Gasa Architects. and the team spent approximately six months working with the contractors to educate them about these systems. Building design The overall building was designed so that its inner courtyard was protected from pollution sources, such as traffic, and the building itself was oriented to take advantage of the maximum amount of solar energy and the lowest amount of cold air movement. The north wall, for example, is a loadbearing, double-skin construction in brick with 200 mm (8 in.) of glass wool insulation to minimize heat loss (building regulations required at least 150 mm (6 in.) insulation). The 7. Facade spring/autumn 8. Facade summer 9. Facade winter Klosterenga s triple-glazed southern facade. Graphic courtesy of Gasa Architects. 2 Canada Mortgage and Housing Corporation
architects noted that, although this is an old style of construction, it is not often used today and most residential buildings feature wooden facades instead. The double-skin construction resulted in a breathing wall that not only added thermal mass to the building and regulated temperature and humidity variations, but also eliminated the need for a vapour barrier. Interior walls to the north, east and west were constructed of unrendered brick and partitions were constructed of plasterboard on steel framing with lowor zero-voc finishes. Floor finishes consisted of linoleum, ceramic tile and wooden parquet. The southern facade is triple-glazed and comprises an outer, double-glazed, low-e glass wall and an inner, single-glazed, wood-framed glass wall with a 300 mm gap (11.8 in.) in between. This gap allows incoming air to be pre-heated, improving thermal comfort in the living areas. A heat pump also recovers heat from the ventilation air. Windows along the south wall can be manually opened to the inside in cold weather to receive the pre-heated air, or to the outside during warm weather when excess solar heat could overheat the apartment. Each apartment was designed by zone, depending on the needs of particular rooms. For example, rooms that need stable heating, such as bathrooms, were located in the middle of the unit, while rooms requiring less heat, such as bedrooms, were located on the north side of the building. Most of the living areas family rooms, kitchens, etc. were sectioned into a variable temperature zone located on the south of the building. Construction materials Most of the construction materials used were produced in Norway and were selected based on their energy efficiency and recyclability at the end of the building s lifespan (e.g., bricks, steel, etc.). Although all finishes chosen were low-voc, because the majority of the exterior and interior walls are brick, this eliminated much of the need for painting or other finishing treatments. Project Data (collected in 2000) Insulation Area (m 2 ) U-Value (W/m 2 K) / R-Value Ground floor 500 0.22 / R 4.5 Roof 500 0.15 / R 6.6 External wall 880 0.22 / R 4.5 Window area 945 1.4 / R 0.7 The standard building requirement for windows and doors in Norway is a U-value of 1.4 W/m²K. During construction all material waste was also sorted for recycling, which in turn reduced the cost for waste delivery. Solar Energy Systems The building was designed with a building envelope that acts as a solar collector to maximize passive solar energy gain. A combisystem active solar hot water system was also supplied to supply both space heating and domestic hot water demands. Living areas were constructed along the southern wall. Here, the outer and interior glass walls show how the interior windows can be manually opened or closed depending on the outside temperature. Photo courtesy of GASA Architects Canada Mortgage and Housing Corporation 3
Active Solar Hot WaterSystem The roof was outfitted with 80 solar panels (218 m 2 [2,346 sq. ft.] active area, 245 m 2 [2,637 sq.ft.]gross area) at a 30- degree angle. The collectors are used to heat water which is stored in six storage tanks (total heat storage 6 m 3 [212 cu.ft.]) under the roof on the 7th floor. On average, the collectors provide 80,000 kwh of heat per year. The solar collector consists of two-twinwall absorber sheets made of high temperature- resistant plastic fixed onto an aluminum frame. The cover shield allows light to pass through but isolates the solar energy collected from heat loss through radiation and convection. Solar radiation is converted to heat in the absorber sheets. Water trickles through the channel structure and absorbs the heat, and the water is then pumped to six domestic hot water storage tanks. The six tanks provide domestic hot water (DHW) to the building. This pre-heated water is transferred to two external DHW tanks and the hot water in the tanks is mixed with cold water to obtain a delivery temperature of between 45ºC (113ºF) and 50ºC(122ºF). The domestic hot water can be heated during the day by the solar energy system or during the night by taking advantage of low-cost night tariffs for electricity. Space heating is provided by a second set of space heating water storage tanks (6.5 m 3 ). A thermostat-driven pump transfers solar heated water from the domestic hot water storage tanks to the space-heating water storage tanks when the temperature of the domestic hot water exceeds the temperature of the water stored in the space heating storage tanks. Two electric heaters in the space-heating storage tanks supply any necessary auxilliary energy. The hot water from the space-heating storage tanks is then used in a lowtemperature subfloor radiant heating system. The water temperature is limited to 40ºC (106ºF) in order to protect the floor heating system. When outdoor temperatures are colder, a dynamic thermostat function compensates for higher space heating demand by increasing the heat store temperature. Passive System The southern side of the building features a double-glazed glass facade, 30 cm (12 in.) in depth, coupled with an interior glass wall (temperatures within the double glazing can vary from below 5 C [41ºF] to almost 50 C [122ºF]). The glass wall system not only provides additional insulation and passive solar gains to pre-heat incoming ventilation air, but also allows for maximum daylighting. The interior windows can be opened or closed manually, and residents can also lower or raise Venetian blinds that are mounted in the air space between the two glazing sections. Water Several water conservation techniques were used in Klosterenga, including water-conserving indoor fixtures, an on-site greywater purification system, rainwater collection and partial green roofs. Eighty solar panels were installed on the Klosterenga roof. Solar energy is stored in storage tanks under the roof on the 7th floor. Photo courtesy of GASA Architects. Water conserving fixtures and rainwater capture Each apartment is equipped with low-flow faucets and showerheads, front-loading washing machines and 4L (1 gal.) toilets. Greywater from kitchens, baths and laundry is pumped to a treatment system for reuse (see next page). Water metering at Klosterenga during the first year showed that the annual consumption of potable water was about 45,500 L (12,019 gal.) per person, less than half the Canadian per capita annual consumption of water. 5 Each apartment also has a dual waste-pipe system. Toilet waste is pumped directly to the municipal sewage system while greywater is pumped to the greywater filtration system in the courtyard (see below). Rainwater is also captured in rain barrels and used in the garden. 5 Tor Helge Dokka. Low Energy Buildings in Norway. Centre for Renewable Energy. Accessed at: http://www.dtu.dk/upload/centre/lave/30-11-2006%20konference/norwegian%20low%20energy%20buildings.pdf 4 Canada Mortgage and Housing Corporation
All greywater is purified on-site. Some water is reused in landscaping, but most is discharged to the stormwater system; eventually, the greywater will be discharged to a local stream. (Note that the number of apartments is incorrectly listed in the photograph as 33). Graphics courtesy of GASA Architects. Greywater purification In the courtyard of Klosterenga, a combined biological filter/constructed wetland system treats the greywater, which is then reused for landscaping (irrigation), in-house use and groundwater recharge. Greywater is first pumped to a septic tank buried beneath the courtyard. It is then pumped to a vertical downflow single-pass aerobic biofilter, then through a porous subsurface filter for irrigation. The effluent from the pond will eventually be discharged to a local stream once it is reopened; currently, the water is discharged to the stormwater sewer system. Green roofs The roofs of storage rooms and waste/recycling collection sheds were covered with sedum plants. Sedum plants are typically used for green roofs because of their low-growing and drought-tolerant characteristics and the fact that they thrive in a shallow-growing medium. The green roofs help to reduce stormwater runoff. Waste management No specific goals were set for residential waste management (e.g., waste reduction, recycling, etc.). However, all organic waste produced by the residents is composted in an on-site composting reactor (housed in the recycling shed) and the compost is used in the landscaping. Each apartment also has four built-in containers for different fractions of recyclable materials. Residents / Sustainable Transportation Boligbyggelag USBL and the architects held a meeting for all new residents to educate them about the environmental features of the building. A simple user s handbook was created for residents, which provides tips on reducing energy and water. Because the building is situated near the city centre, Klosterenga residents have convenient access to the city s public transportation system. In addition, extensive bicycle parking and covered bicycle sheds are provided on-site. Results Energy use for a building of this type and size is normally between 150 180 kwh/m 2 /yr. The design team s goal was to achieve an energy use of approximately 104 kwh/m 2 /yr 6. Monitoring during the first full year after the building was completed, however, showed energy use to be about 127 kwh/m 2 /yr. The difference was attributed to three things: 1. Poor technical performance of the solar collectors during the first year, which occasionally took the solar collectors out of operation. Certain elements in the collectors needed to be replaced within the first year of operation. 2. Some residents exceeding the average estimated energy use. During the first year, most apartments averaged 4,000 kwh/yr in energy use, while three apartments used 22,000 kwh/yr. 3. Actual indoor temperatures being maintained at higher temperatures than the 20ºC (68ºF) estimated baseline, which increased space heating energy consumption. 6 Housing Prices Shoot Up Again. Aftenposten, News from Norway. May 21, 2008. http://www.aftenposten.no/english/business/article1620736.ece. Canada Mortgage and Housing Corporation 5
When these deviations were corrected, the actual consumption was found to be 102 kwh/yr, slightly lower than the original goal. All monitoring took place between 2001 and 2002. As of May 2008, the architects reported that there had been no substantial changes in consumption since the initial monitoring. The municipality of Oslo also benefited from the example provided by Klosterenga. The city used the building as a model when a state hospital was moved and the site was transformed into a 680-unit housing area known as Pilestredet Park. The two architectural firms involved in Klosterenga were hired to prepare a portion of the design for the new housing area. Financial The total cost for the building was approximately $5M Cdn, or about 15%-20% higher than the reference building at a nearby site. The project received grants from six different sources (the European Commission s European Housing Ecology Network, the Housing Bank of Norway, the Research Council of Norway, the City of Oslo, E-CO Smart Norway, and the Norwegian Water Resources and Energy Directorate), which covered 50% of the added cost. USBL covered 37% of the added cost, while buyers covered the remaining 13%. When Klosterenga was first built, the average unit sale price was about $244,000 Cdn (1,240,000 Norway Kroner [NOK], or about $3,250 Cdn per square meter). Since then, real estate prices in Oslo have skyrocketed, with the average price for flats in the city averaging about $7,500 per square meter. The average annual energy bill for a similar-sized apartment in Oslo is just under $2,000 Cdn (about 10,000 NOK). Yearly energy bills for the Klosterenga apartments have averaged $1,200 Cdn (6,000 NOK), a 60% reduction in energy costs. Evaluation Evaluations by third parties have been performed of individual aspects of Klosterenga and links to these evaluations and case studies are listed in the Sources section below. USBL has not conducted any follow up with residents to determine behaviour changes, or emission or energy/water use reductions. Contacts Mr. Roral Viken Boligbyggelag USBL E-mail: roar.viken@usbl.no Website: www.usbl.no Mr. Per Monsen Gasa Architects AS E-mail: per.monsen@gasa.no Website: www.gasa.no Covered bicycle parking is featured in the photo above. Photo courtesy of GASA Architects. 2009, Canada Mortgage and Housing Corporation Printed in Canada Produced by CMHC 25-03-09 Revised: 2007, 2008, 2009 66356 Although this information product reflects housing experts current knowledge, it is provided for general information purposes only. Any reliance or action taken based on the information, materials and techniques described are the responsibility of the user. Readers are advised to consult appropriate professional resources to determine what is safe and suitable in their particular case. Canada Mortgage and Housing Corporation assumes no responsibility for any consequence arising from use of the information, materials and techniques described.