Comparison of the energy consumption of ground-source and air-to-water propane heat pumps for the heating needs around Europe.

The most widely used refrigerants for heat pump applications in Europe are HFCs. These refrigerants have a significant direct contribution to global warming. For this reason, they are being phased-out, as established by the so-called F-gas Regulation (EU Reg. 517/2014). Propane is among the possible substitutes for heat pumps used for space heating and cooling. This work aims to evaluate the potential of propane heat pumps focusing on the type of source of energy adopted: ground and air. A ground coupled water-to-water and an air-to-water heat pumps were modeled and their performance parameters were correlated as a function of the boundary conditions at both the evaporator and the condenser. Different climates typical of average, warm and cold regions of Europe were investigated. For each of these regions, a user type was identified and a heating demand profile was used, also taking into account the characteristics of the existing building stock. In order to assess the units, an integrated model of the system was developed in TRNSYS including the heat pump, the climatic conditions, the controls and the thermal load. Results obtained led to the conclusion that energy saving can be achieved by exploiting different technologies depending on the type of user and on the climate taken into account.