The Fraunhofer Institute for Solar Energy Systems ISE has made significant progress in the development of heat pumps by creating a functional model of a refrigeration circuit that utilizes propane as a climate-friendly and cost-effective refrigerant alternative.

“The project goal was to develop a nearly market-ready heat pump module which uses the climate-friendly refrigerant propane, does not exceed the 150-gram limit for indoor use and yet still provides sufficient heat for single-family homes,” says Dr. Lena Schnabel, Head of the Heating and Cooling Department at Fraunhofer ISE. “We have now achieved this goal in cooperation with our industry partners and have given them the tools to develop a market-ready heat pump.”

This breakthrough innovation aims to address the issue of environmentally harmful refrigerants still being used in many heat pump devices. The research team, in collaboration with an industrial consortium, successfully achieved impressive results with a brine heat pump that utilized only 146 grams of propane but delivered a heating capacity of 11.4 kilowatts.

This low refrigerant charge allows for the installation of the unit indoors without extensive safety precautions. Compared to existing systems on the market, the Fraunhofer ISE model requires just one-fifth of the propane amount per kilowatt of heat output.

The project was funded by the German Federal Ministry for Economic Affairs and Climate Action and shows promise in driving the transition towards sustainable heating technologies.