EUDP13-I, Hybrid heat pump for district heating

In this way the district heating companies can reduce the natural gas consumption and replace it by wind generated electricity. Loegumkloster District Heating will host this installation.

We want to apply a so called hybrid heat pump which is assumed to be even more energy efficient than traditional compression heat pumps and will be able to supply heat at a high temperature that can be used directly in the DH grid. At the same time it will produce chilled water which can be used in other heat generating units, e.g. the solar heat panels. This will improve the thermal efficiency and extend the annual operating hours of these units.

In this project, the hybrid heat pump will be installed in a parallel with other heat generating units, i.e. gas engine, gas boiler, solar heat panels and a wood pellet driven absorption heat pump. At all times the DH Company will use these production units in the most cost effective way, supplying DH heat to its consumers. A major challenge in this project is to make a system design so flexible that it allows the hybrid heat pump to become an economically viable alternative to the gas engine and boiler, thus replacing fossil fuel and enhancing the use of sustainable energy sources.

The project aims to integrate a 1320kW electrical driven heat pump at Loegumkloster District Heating Company in parallel to other heat generating units, i.e. gas engine, solar heat panels and absorption heat pump.

The “hybrid” denomination means that the refrigeration cycle is a combination of compression and absorption principle using a solution of water and ammonia as refrigerant. It is anticipated that the resulting COP (Coefficient of Performance) will be higher than that of ordinary compression heat pumps.

The hybrid heat pump will be tested under a wide range of temperatures and the resulting COP will be documented for each case. The heat pump shall be able to operate with temperatures in the range of 17 °C to 40 °C on the evaporating side and up to 85 °C on the condensing side. Depending on temperature conditions we expect COP up to 4,5. It is our ambition to make a highly adaptable plant design so that the heat pump can support and complement other heat generating units in the best way.

The project is divided into 4 work packages, a) detailed design, b) implementation, c) measuring program and d) project management.

The project results will be disseminated through relevant magazines, through seminars and through IEE-project SDH plus targeted to district heating companies and employees in Denmark and EU27.