Innovative Energy-Saving Technology Based on Heat Pumps

researcher's name
about researcher SAITO, Kiyoshi Professor
Faculty of Science and Engineering School of Fundamental Science and Engineering
research field
Intelligent mechanics/Mechanical systems,Dynamics/Control,Thermal engineering


Energy-saving efforts, including CO2 emissions reductions, are being linked to the global calls for CO2 reductions in recent times. Meeting Japan’s target of a 25% reduction in CO2 emissions from 1990 levels by 2020 will be extremely difficult. Under the “Cool Earth 50” program, the Japanese government supports entities which contribute to energy conservation. However, Japan needs innovations in energy use technologies through the collective efforts of energy suppliers, manufacturers, and users.


This technology is characterized by two principles. First, heat moves from hot things to cold things. Secondly, if gas is spewed out all at once from a high-pressure area to a low-pressure area, then the gas is cooled rapidly. This technology is expected to have significant energy conservation potential depending on the operating conditions. Furthermore, with the development of smart systems, it will become important that optimal energy systems are operated with heat pumps forming the crux of the systems.


Cooling and heating equipment applications (for household use, for business use, for industry use, automobiles). Refrigerator, vending machine, hot water supply, clothes dryer of a washing machine, and snow melting. The demand for heat pump technology for automobiles is anticipated to increase due to the expanded use of electric vehicles, and therefore, in order to increase their travel distance. This technology may also be applied to cope with the heat island phenomenon. In addition, in the industry sector, thermal energy is supplied, stored, transported, and used in a variety of forms, including electricity, fire, steam, hot water, cold water, and dry air. Innovation is needed to enable the use of this technology through an optimal combination of energy. 


Heat pumps are a highly energy-saving and eco-friendly technology, and Japan’s is among the leading technologies of the world. Heat pumps are a vital technology that the Japanese government included in the list of 21 technologies that would be given priority in its Cool Earth-Innovative Energy Technology Program. This technology is expected to have significant energy conservation potential depending on the operating conditions. Both manufacturers and the government are putting efforts into increasing the performance of the technology and promoting its adoption.

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posted: 2014/05/21