UPDATE: Norwegian housing cooperative wins prize with Green & Cool CO2 units

By Janet Thompson, Jan 23, 2015, 11:34 3 minute reading

The Tveita housing cooperative, located in Norway, won the Varmepumpeprisen 2013 (heat pump prize) for its use of eco-friendly CO2 Cool Mistral units, delivered by Green & Cool’s Norwegian dealer Kuldeteknisk AS. Mads Borgen's 'Analysis of CO2  Heat Pumps for Hot Water Heating in a Block of Flats' - a thesis written at the Norwegian University of Science and Technology (NTNU) - looks into the energy efficiency of the CO

The Tveita housing cooperative, located in the eastern districts of Norway’s capital city Oslo, is one of the country’s largest. Completed in the late 1960’s, the buildings comprised 819 apartments. In the autumn of 2010, the housing cooperative fitted the first major heat pump installation in Norway to use eco-friendly CO2 as the refrigerant. The installation consists of three Green & Cool Mistral units delivered by Green & Cool’s Norwegian dealer, Kuldeteknisk AS.

About the System

The three Green & Cool Mistral 100 kW heat pumps for domestic hot water were installed in each of the housing cooperative’s three 13-storey buildings. One of the many advantages of using CO2 as a refrigerant is its ability to achieve higher temperatures. These heat pumps can raise the temperature from around 8°C till 70°C in a single stage. The heat source is the exhaust ventilation air, which keeps a constant temperature all year round. Each building is equipped with an 8,000 litre accumulator tank.

The heat pumps have a seasonal heating performance factor of 4 and energy savings of over 75% compared to electric domestic hot water heaters. With a total investment of NOK 31 million, which included heat pumps for space heating, the installation resulted in annual savings of nine million kilowatt-hours. This reduced annual costs by around NOK 6 million (approximately EUR 800,000) and energy consumption fell from 279 kWh to 138 kWh per square metre per year. The payback time is, therefore, only five years.

Heat Pump Prize 2013

The Tevita housing cooperative has now won the Varmepumpeprisen 2013 (heat pum prize) for its successful work in radically reducing energy consumption. The award is conferred by the Norwegian Heat Pump Association (NOVAP).

“It’s always pleasant to get recognition for work done, and the Varmepumpeprisen award for 2013 naturally means more people have become aware of how good Green & Cool’s CO2 heat pumps are. We have already noticed an increase in demand from others,” says Frode Berg, Technical Manager at Kuldeteknisk AS. Ole Morten Øversjøen of the Tveita housing cooperative, who recommends that other housing cooperatives invest in heat pumps to reduce their energy consumption as well, points out that it is also important to engage capable advisers in the running-in period, to ensure that the installation is set up to run optimally.

78 % energy savings compared to domestic hot water heating with electric heaters 

Mads Borgen, from NTNU, has undertaken research on the energy efficiency of the CO2 Cool Mistral units at the Tveita housing cooperative. The data, which was collected in 2014, demonstrates that the CO2 heat pumps are highly energy efficient. Given the temperature differential of the heat source between summer and winter months, there were varied results for the performance of the heat pump's gas cooler as well as for the coefficient of performance (COP). During the winter the maximum COP was at 4.5 and 5.2 during the summer, while the heating seasonal performance factor (SPF) of the heat pump was calculated at 4.5. This means that the energy savings equal 78 % compared to domestic hot water heating with electric heaters.

About Green & Cool

Since it began distributing high quality CO2 refrigeration systems in 2007, Green & Cool has grown into one of the leading global suppliers of CO2 refrigeration systems. The Swedish refrigeration expert provides CO2 systems for supermarkets, convenience stores, the food industry, air conditioning, industrial processes, and heat pumps.

Vist Green & Cool's partner page


By Janet Thompson

Jan 23, 2015, 11:34

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