22 May 2002

A2-06 Innovate hot water supply technology conductive to arresting global warming. – Development and significance of CO2 heat pump water heater- K.Kusakari (Japan)


The need to promote energy-saving efforts and reduce CO2 emissions at home is increasing. Particularly, “hot tap water supply” which accounts for about 35% of residential final energy consumption, now depends largely on direct combustion of fossil fuels such as gas and oil.

Against such a background, The Tokyo Electric Power Co., DENSO CORP., and Central Research Institute of Electric Power Industry have jointly developed a CO2 heat pump water heater for residential use, which uses a natural refrigerant (carbon dioxide) that has very little impact on global warming, and boasts a very high coefficient of performance (COP). After performance evaluation and service tests of a field testing machine, we have made it available in the market for the first time in the world.

The CO2 refrigerant heat pump water heater we have recently developed boasts very high efficiency with a coefficient of performance (COP) of more than 3.0 a year on average. Compared with conventional combustion type water heater, our new water heater saves energy by about 30%.