LAUSR

Abstract Natural gas is widely used for space heating because of its low pollutant emissions and high combustion efficiency. Nevertheless, the primary energy efficiency of a gas-fired boiler cannot exceed 100% based on high calorific value. In order to improve the efficiency of natural gas for heating, a gas-fired hot water system with a compression-enhanced ejector heat pump is proposed. The simulation results show that the compressor can sustain the ejector’s high efficiency range while in operation. When the ambient temperature is 0 °C, the primary energy efficiency is substantially higher than that of the conventional ejector heat pump system and gas-fired boiler by 40 and 36%, respectively. When the supply water temperature does not exceed 46 °C, the coefficient of performance and primary energy efficiency of the novel gas-fired hot water system can reach 1.65 and 1.22, respectively.