22 May 2008


Japan is now striving to attain the lower greenhouse gas emission target set in the Kyoto Protocol. Doing so promptly requires a significant reduction in CO2 emission levels in transportation, commercial, and residential applications because increasing CO2 emission
levels are seen in these three areas. Water heating accounts for 20% of energy consumption in commercial use. Japan has difficulty in substantially reducing the CO2 emission level resulting from water heating, because most water heaters in Japan are combustion-based water heaters, which employ gas, petroleum, or other similar resources as heat sources. In order to meet end-user demands, such as lower CO2 emission levels, ensured safety, and lower costs, we have developed a high-efficiency heat-pump water heater for commercial use. Beginning initial research towards commercialisation in 2004, we strove to increase the capacity of the prototype, and in 2007 finally succeeded in commercializing a large-capacity water heating system that can supply 40 tons of hot water each day. Compared with gasfueled water-heating systems, the heat-pump water heater is capable of reducing the primary energy consumption by approximately 40% and the CO2 emission level by approximately 50%. We describe an overview of our product and report its features, in the hope that this type of product will spark global adoption of heat-pump water heaters.