抄録
Heat pumps using CO_2 as a natural refrigerant have been developed, and are expected to contribute to energy saving in hot water supply. In residential applications, CO_2 heat pumps are used in combination with hot water storage tanks. The objective of this paper is to analyze the overall performance of a hot water supply system composed of a CO_2 heat pump and a hot water storage tank by numerical simulation. A simulation model is created based on thermodynamic equations for all the components of the system. The performance an improved system with hot water extracted from top and middle positions of the tank is analyzed. It is shown that the performance of the improved system is superior to that ofa conventional one.
