NEXT GENERATION OF HEAT PUMPS WORKING WITH NATURAL FLUIDS: NxtHPG PROJECT RESULTS

NxtHPG project ‘Next Generation of Heat Pumps working with natural fluids’ is a Research and Development project partially funded by the European Union under FP7, which has been recently finished. NxtHPG project targeted the development of a new series of safe, reliable, high efficiency and high capacity heat pumps working with natural refrigerants (namely: Hydrocarbons and CO2) in several applications where the take-off of this technology could be reasonably short. The project involved a large group of OEMs of both components and heat pumps who provided their best technology to reach the project objectives. This paper presents first the structure and main objectives of the project, and then a brief description of the 5 different heat pump prototypes which were developed; three employing propane as refrigerant and two employing CO2. 1. Geothermal heat pump; 2. Roof-top air to water heat pump (both reversible so able to produce both heating in winter and cooling in summer); 3 Heat pump booster to directly produce sanitary hot water from waste heat water streams, as per example from sewage water or condensation loop; 4 CO2 air heat pump for the production of high temperature hot water; 5 CO2 air heat pump for substitution of boilers in high temperature radiator heating systems. Prototypes capacities were around 30 to 60 kW but could be easily scaled up to larger capacities. The paper then presents a summary of the experimental performance of the final design of the different developed prototypes and finally, the conclusions that can be drawn from the performed development work.