An Innovative Air—Water Heat Pump with Ecological Refrigerant

The heat pump market is growing year on year and more than 20,000 units were sold in 2015 alone. The majority were air to water heat pumps for heating or for only warming up domestic hot water utilizing inside air. The project ordered by Kołton S.C. company, co-funded by Regional Operating Programme 2014–2020 of the Lesser Poland Region, was conducted in the AGH-UST Educational and Research Laboratory of Renewable Energy Sources and Energy Saving in Miękinia and had the following goals: defining the type of air-water heat pumps, determining the refrigerant, design, developed and testing the prototype. According to EU F-gas regulations, the use of refrigerant with high GWP (Global Warming Potential) will be limited. It was one of the reasons to develop a heat pump using an environmentally friendly and natural refrigerant—R290. The type of construction used in the heat pump is monobloc, which simplifies the installation. It uses components dedicated for R290, such as a scroll compressor, evaporator and condenser, 4-way valve, electronic expansion valve, etc. The first tests of the device gave the following results: for an air temperature of 2 °C and a water temperature of 35 °C the heating power was 13.2 kW and COP was 3.69. Further tests will be conducted to optimize the parameters of the heat pump and the controlling algorithm.