Investigations of thermal performance of ejection refrigeration system driven by low grade heat

Buildings represent a very high energy consumption percentage compared to other economy sectors. Technologies dealing with energy savings, reduction of the energy consumption and efficiency improvements are highly desirable. Paper presents the system proposed for the air-conditioning purposes which utilizing the hot water in heat distribution network as a motive heat in summer season. The proposed refrigeration system is equipped with gas ejector. The system is operating with pro-ecological refrigerant R-1234ze(E). The paper presents the results of the experimental investigations. The thermal capacity of the heat source was 100 kW. Water was the heating medium with temperature below 65 °C. Two evaporation temperatures 0 °C and 6 °C typical for low and medium temperature air-conditioning systems were set in the experiments. The operation of the regenerative heat exchanger applied for R-1234ze(E) is analysed for the first time for the case of the ejection systems. The features of operation of the ejection system on the basis both external and internal parameters were analysed. The system achieved COP = 0.25 for evaporation temperature 0 °C, and COP = 0.40 for 6 °C. It was showed that the internal heat transfer improved COP of the system for approximately 10-12%.