Denmark has a target to meet 55% of its energy demand with renewable production until 2030. While the electricity was already 64% renewable in 2017, the challenge lies within the heating sector. This creates perfect conditions for wide implementation of heat pumps.

Two areas of interest for implementation are district heating systems and industrial applications. For district heating, this is already demonstrated through several successful installations. The focus there now lies on upscaling and operation as well as on exploiting further benefits. The development regarding industrial installations is not as strong. There the focus lies on simplifying the optimal integration of heat pumps and enabling higher supply temperatures.

For district heating applications of heat pumps, the request is increasing due to a number of concurrent factors. One is that district heating operators are legally obliged to consider the socioeconomic cost as the main criterion. Combined with decreasing electricity prices and available subsidies for integrating heat pumps as an energy efficiency measure, this makes heat pumps more interesting for district heating operators. At the same time, the technology has matured on the market and is now considered well-known and acknowledged.

Some new applications are tested in Denmark, e.g., an installation in a district heating grid connected to a warehouse, and a cruise ship terminal, creating an island configuration without connection to the larger city network. In this system, flexible operation can be tested, exploiting secondary benefits such as cost optimal operation, peak shaving of the district heating demand and delivery of ancillary services to the power system. Further development is expected, but initial tests show that it is possible to deliver secondary and tertiary reserve power.

In comparison, integration of heat pumps in industrial applications is rather challenging. The boundary conditions are more diverse, the level of integration can vary, and the available technologies do not cover the entire range of applications. Regarding the level of integration, it is found that the highest performance regarding thermodynamics and economy is reached when the heat pump is integrated at the utility level, with a high degree of integration with the process. On the other hand, integration at the process level enables a gradual implementation and may be more appropriate for integration in existing plants.

Another challenge regarding industrial applications is that the temperature demand is often higher than what a heat pump can deliver. The demand could be as high as 300 °C, while heat pumps supply up to 150 °C. Nevertheless, it is expected that the development will continue and that the demand for industrial heat pumps will increase accordingly.

Benjamin Zühlsdorf, Wiebke Meesenburg, Pernille H. Jørgensen and Brian Elmegaard, Denmark



The text has been shortened by the HPC team


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