Via EUREC Member, Fraunhofer ISE

The Fraunhofer Institute for Solar Energy Systems ISE is developing a compact and cost-efficient refrigeration circuit for heat pumps which use propane as refrigerant in the research project “LC150 Development of a Refrigerant-reduced Heat Pump Module with Propane”, funded by the German Federal Ministry for Economic Affairs and Energy BMWi.

A broad industrial consortium of European heat pump manufacturers is now financially supporting and technically accompanying the development in the project. The joint development platform will open up considerable cost reduction potential to the participating companies and accelerate the industrial development of heat pumps for residential buildings. 

As the EU regulation on fluorinated greenhouse gases mandates a 70 decrease in harmful emissions from refrigerants by 2030, propane is becoming increasingly important as natural refrigerant. Its excellent thermodynamic properties allow for a higher efficiency compared to conventional heat pumps. At the same time, the global warming potential is 500 times lower than the GWP of the classic fluorinated refrigerants most commonly used today.

In 2019, Fraunhofer ISE succeeded in developing a brine-water cooling circuit using components available on the market. The circuit requires only 150 grams of propane for a heating capacity of 8 kW, which corresponds to a refrigerant reduction of 75 percent compared to systems on the market. A heat pump based on this concept could be placed inside the home without any additional safety precautions.

In the project, the optimization of the performance, efficiency and operational stability are addressed. The decisive factors for the overall optimization are the use of heat exchangers, compressors and piping systems with reduced refrigerant charge and the development of operating modes that allow the refrigerant to be distributed well throughout the components.