Decentral heat pumps for the retrofit of apartments
The replacement of decentral gas boilers, common in many European countries, is a key challenge on the pathway to the decarbonization of building stock. The solution proposed in this work is the stepwise retrofitting of multi-family houses formerly using decentralized gas boilers, using a semi-central system with decentral apartment heat pumps in the dwellings. Building on promising simulation results from a research project, demonstration in a real building has shown that a semi-central heating system can avoid distribution losses, stop worst-case design, and enable an incremental retrofit, offering a wide range of applications. Within a research project, a small-scale R290 heat pump for apartment-wise deployment has been developed based on requirements explored in a serially retrofitted multi-family house (MFH). In a second use-case, a semi-central heat pump system has been already implemented. First measurement results show a good adaption to different supply temperature levels and a good overall system coefficient of performance (SysCOP).