A-57 Survey on hot water usage of CO_2 heat pump water heater in houses : Part 5 Running condition of CO_2 heat pump for hot water supply system

Abstract

The field measurements of the loads of hot water demands and the performance for the CO_2 heat pump water heaters were carried out in 14 houses located at the regions of different climates for over a year. In this paper, based on the measurement data, the characteristics of running conditions for the CO_2 heat pumps are analyzed in details. The effect factors for the COP of heat pumps and systems are analyzed with the multiple regression analysis technique. As for the residual hot water in storage tank, which seems to influence the COP of systems, the relationship the required hot water temperatures and the volumes of thermal storage are shown.