Large Heat Pumps in German District Heating Systems
As part of living lab “Reallabor_GWP – Large Heat Pumps in District Heating Networks – Installation, Operation, Monitoring and System Integration” initiated and coordinated by the German district heat association, the implementation of large scale heat pumps coupled with district heating technology has been scientifically supported at five locations in Germany since 2021. The first system was commissioned in 2023. Four of the systems are now in the R&D commissioning phase, which is accompanied by an in-situ measurement campaign. The article presents the five locations with regard to the current generation portfolio and identifies the challenges for integrating the heat pumps into the hydraulic and electrical system aside. Based on the requirements at the respective locations, the specifics of the heat pump solution selected are explained. In addition, the installed refrigeration circuit processes are compared. Challenges in the commissioning phase are highlighted. Using the scientifically prepared measurement data, key characteristics such as COP and temperature lift as well as the number of start-stop cycles are analysed to underline the dynamics related to cost of electricity.