Gråsten District Heating

Project purpose and mode of operation:

To cool the flow temperature of the water to the district heating plant's solar collector system installed in 2012 and thereby increase the efficiency of the solar collectors. The absorption heat pump can produce 700 kW. Effective collector area of 19,024 m2 with an expected annual production of 9,700 MWh.

The absorption heat pump's chilled water circuit produces cold water down to around 13°C, which is used to exchange with the collector circuit. Energy is absorbed from the flow water to the collector circuit, which is fed back to the heat pump evaporator, thereby transferring the energy to the heat pump absorber. The absorber is traversed by return district heating water, which in series with the heat pump condenser delivers heated district heating water at around 70°C. This transfers heat from the flow water to the solar collector circuit into the district heating, thus improving the efficiency of the solar collector while utilizing the heat in the district heating network. The heat pump is powered by hot water at around 150°C, which means that the electricity consumption for such a machine is minimal.

SEG A/S role:

To deliver, install and commission the absorption heat pump for the customer Gråsten Fjernvarme and to train the operating staff in the use of the machine.

Ramboll was the consultant on the assignment.

Description of the project content:

The absorption heat pump consists of the following areas;