New resident Jan Grubert had a shock when he received the first heating bill on his 230sqm apartment on Østerbro in Copenhagen in 2009.
“I didn’t believe it could be right at all; that I had to pay so much money while the indoor comfort was so poor. I showed heating bills from my old apartment to my neighbors and they agreed that the current bill was very high. We had to do something about it,” says Jan Grubert.
Later he was elected chairman of the housing association and took the first step towards cutting heating expenses for the building. He examined the heating system in the basement and saw the Danfoss logo on one of the meters. This led to an agreement with Danfoss for the service concept EnergyTrim™.
Planning a party to celebrate the savings
And today, Jan Grubert’s initiative has come to fruition. The residents in the five-storey building will be paid back a total of around 13,400 EUR on their heating bills in 2012.
“We have talked about maybe having a small party to celebrate the good result,” he says.
The agreement to purchase Danfoss EnergyTrim™ meant that service technician Erik Probst began to examine how the heating system worked. He suggested that some improvements be implemented. Two elements, in particular, have optimized the heating system for the residents: return water to the district heating plant is now considerably colder than it was previously, and a new regulator has been installed for the control of both the heat in the radiators and the water temperature in the hot water tank.
In total, the residents used 25 percent less heat in 2011 and optimization expenses in 2012 will amount to around 13,400 EUR.
The building dates back to 1895 and there are many more similar properties in Copenhagen which would experience the same kind of increased comfort, if their heating systems were optimized.
Read what they did to improve the heating system
The improved cooling of the water supplied by the district heating plant has had a very positive effect on the heating bill. The district heating plants reward consumers for returning water at as low a temperature as possible.
On the other hand, the plant imposes a penalty fee if the return water is not cold enough. Many plants have set a limit of cooling at 30° Celcius; if it gets below that, the consumers must pay a fee. Cooling of between 30° and 35°C will not result in a fee, but if 35°C is exceeded, a reward will be given for efficient cooling.
Efficient cooling of the return water means improved operating economy at the district heating plant. When the contract was made in 2009 between the housing association and Danfoss, the annual cooling was 4.6°C – in 2011, it was 31.2°C.
At the same time, a new piping system was constructed; adjusting the heat circulation pump to operate with flow pipes instead of return pipes.
Before the change, the old pipes had a very large division of layers which meant that hot water did not flow through some of the riser installations in the radiators but rather the cooled water, which had already circulated in the system, depending on where the branch pipe was mounted on the distributing pipe.
Now that the circulation pump is mounted with flow pipes, the water is mixed before being pumped into the radiators so that all of the riser installations are at the same temperature and all of the apartments and rooms are kept at a comfortable indoor climate.
Danfoss EnergyTrim™ is a special service concept developed in Denmark. It consists of a range of services which ensure optimal operation and maintenance of the heating system.
An important part of the concept is periodic checks to reduce energy consumption. Danfoss EnergyTrim™ is particularly aimed for use in Danish companies, municipalities and housing associations.
Pictured to the right: The building dates back to 1895 and with an improved heating system residents used 25 percent less heat in 2011.