The Fraunhofer Institute for Solar Energy Systems ISE has presented the prototype of an environmentally friendly heat pump . The refrigerant used is propane gas, whose greenhouse gas potential is about 500 times less than conventional refrigerants and therefore extremely low. Another advantage is that the 150-gram brine-to-water heat pump presented here requires only around one fourth of the refrigerant compared to conventional heat pumps available on the market at the same power. According to the developers, such a heat pump can be installed indoors without the need to implement additional safety measures and then reaches around 8 KW heating power. Per kilowatt it requires only about 20 grams of propane. The prototype was built using standard components available on the market. Heat pumps with the alternative refrigerant propane are environmentally friendly, have a high power yield, and the gas is also available worldwide at low cost.

The search for new refrigerants is necessary, since the first bans on harmful refrigerants will come into force in the European Union on January 1, 2020. EU Regulation 517/2014 , also known as the F-Gas Regulation, mandates a continual reduction of refrigerants that are harmful to the environment. It aims to decrease emissions from refrigerants by 70% by 2030, compared to the base year 1990.