Propane (R290) is a natural refrigerant without global warming contribution. But it is flammable. Because of safety reasons it is good to keep the “charge” (amount of refrigerant in the heat pump) at a minimum. Especially when we use such a heat pump in living areas. That is why we develop a low charge propane heat pump.
In 2017, Saint Trofee designed a R290 heat pump with a heating power of 4 kW and a refrigerant charge of only 150 grams. We built a laboratory prototype and we tested it in our lab. It performed very well according to the design parameters.
In 2018, Saint Trofee filed a patent for an innovative “single pass” heat exchanger with very low refrigerant content. We consider to use it as a heat pump condensor.
Currently, we work on a follow-up (9 kW) prototype design with very low R290 refrigerant content. This design makes use of the innovative heat exchanger.