A-12 Survey on hot water usage of CO_2 heat pump water heater in houses : Part 6. Analysis on hot water usage and hot water demand based on the annual measurements in houses

Abstract

The authors carried out questionnaires in four seasons and conducted field measurements about the hot water usage and the performance for the CO_2 heat pump water heater in eight houses for over a year from February, 2007. Based on the results of questionnaires and measurements, the characteristics of hot water usage were analyzed in detail. In this paper, monthly and daily changes of hot water consumption in each house based on the annual measurements were shown and compared to the results of the last year, 2006.