22 May 2008
In January of 2001, for the first time in the world, Tokyo Electric Power Co.,
DENSO CORP., and Central Research Institute of Electric Power Industry have reported the
practical application of the CO2 refrigerant heat pump water heater for residential use, which
can save more than 30% of energy compared to conventional combustion type water heater.
The government has started a subsidy system in September of 2002, and at the end of
March, 2008, about 1,240,000 of the system have accumulatively forwarded to the whole
market and now it continues to spread around well.
This paper deals with the newest situation of CO2 refrigerant heat pump water heater “Eco
Cute” in Japan, its widespread use situations, performance improvements achieved since
introduction of the first model, variations, user evaluations, efforts by Tokyo Electric Power
Company, programs for supporting the widespread use, challenging issues and future