| Work Detail |
Germany’s Fraunhofer Institute for Solar Energy Systems (Fraunhofer ISE) is developing “easy-to-use and reproducible” propane heat pumps to replace fossil fuel systems in multi-family homes, while exploring retrofit options for various types of residential buildings.
The German institute Fraunhofer ISE is leading a consortium of 20 companies from the heating and housing sector to optimise propane (R290) heat pump systems in existing multi-family homes.
The LC R290 project plans to implement several pilot projects for heat pumps in residential buildings currently using gas or oil heating, with three conceptual approaches proposed.
Fraunhofer ISE noted that the heating load of the buildings considered ranges from 23 kW to 93 kW, requiring a range of heat pumps, including high-performance models.
“A particular challenge is the systems for individual apartments, where everyone has their own gas heating system,” the institute noted. “Solutions are predominantly needed here for small apartments in the low-rent segment. These new system solutions should require as little retrofitting and space as possible.”
One of the three concepts being developed features a heat pump system with a seasonal coefficient of performance (SCOP) of 3.8, a heating output of 6 kW and a sump temperature of 55 ºC.
The second demonstrator is a centrally installed heating system with the heat pump located in the basement of the building. It can use geothermal heat sources, solar thermal, district heating, air collectors or a low-temperature heat network. In the first phase of testing, it achieved a SCOP of 3.65, a heat output of 29.5 kW and a sink temperature of 55 °C.
“Optimisation calculations suggest that the filling quantity could be reduced to 800 g propane and the SCOP could be increased to 3.7 by applying optimised control strategies, for example optimising superheat,” says Fraunhofer ISE.
The third pilot project involves another unspecified type of centrally installed external heat pump for apartment buildings.
“Field measurements on the leakage behaviour of propane are currently being carried out in the Fraunhofer ISE outdoor performance test. These results will provide information on how to further increase the safety of propane heat pumps,” said researcher Katharina Morawietz. “Our goal is to reduce the amount of propane refrigerant in this type of heat pump to a minimum.”
The German Federal Ministry for Economic Affairs and Climate Protection is funding the two-year research project. |
