抄録
Water heating consumes about one-third of total residential energy in Japan. Therefore, addressing the carbon dioxide (CO2) emissions from this energy use is one of the top priorities for Japan in order to mitigate climate change. Further, heat pumps that rely on HFCs pose another problem in the form of direct greenhouse gas emissions, due to their high GWPs. To reduce energy and minimize emissions of both greenhouse gases and ozone depleting substances, CO2 was chosen as a refrigerant. This paper describes how the properties of CO2 are not only suitable for hot water heaters, but why CO2 is actually preferred because of the electric power generating composition and resulting charge rate structure in Japan. It also discusses the latest product development and describes Japanese national policy to expand the use of this type of product in order to reduce climate emissions.
