IEA Heatpump Programm Annex 28





National project

In Japan, recently heat pump water heaters using CO2 have been introduced in the market. Moreover, in Japan, inverter drives are quite wide spread. Therefore, the focus of Japan has been the development of adequate test procedures and calculation methods for these systems.

Fig. 1: System layout of the systems with combined DHW –floor heating tested in the Japanese project

Japan has performed test rig measurements of a CO2-system with combined floor heating and possible additional heat use for radiator heating or drying, which are quite new in the Japanese market. Fig. 1 shows the layout of this system. The single hot water operation is to be tested ac¬cording to the Japanese Standard 4050:2004. Testing is performed for three seasons (winter, summer, intermediate) and three typical days (cold, average, warm) with fixed space heating load profile and tapping profiles for the respective conditions. Testing is performed for the operation modes single DHW and combined SH/DHW. In single DHW, there are the three days cold, average and hot, in combined operation winter mode, the cold and average day are tested, in intermediate season the warm day. By defining tapping patterns, transient effects due to the respective load profile are included in the testing results.
In accordance with this testing approach of JRA 4050:2004 Japan has worked out a calculation method based on a "typical day approach" for the respective seasons. The results of the testing for the respective seasons are weighted with a number of days in the season for all operation modes to receive the seasonal performance of the heat pump operation.
Fig. 2 depicts the tested heat pump system and its specifications.

Fig. 2: System layout of the systems with combined DHW –floor heating tested in the Japanese project

Japanese national team IEA HPP Annex28
National Team Leader:  
University of Tokyo
  The University of Tokyo
Institute of Environmental Studies
Prof. Dr. Eiji Hihara
7-3-1 Hongo
Tokyo, Japan
Phone: +81 3 5841 6323
Fax: +81 3 5841 6323
National Team:  
Tokyo Electric Power Company Tokyo Electric Power Company, R&D Center
Hirofumi Ida
4-1,Egasaki-cho Tsurumi-ku
Japan is represented by a national team with numerous participants. The national team leader is the University of Tokyo. The Heat Pump and Thermal Storage Technology Center of Japan (HPTCJ) has organised a task force of the companies DENSO Co., Toshiba Carrier, Daikin Industries, Mitsubishi Electric, Hitachi Air Conditioning Systems, Hitachi Home and Life Solutions, Sanyo Electric and Matsushita Electric Industries, which are active in the Japanese heat pump market. Moreover, the utilities TEPCO (Tokyo Energy Power Company), Kansai Electric Power Company and Chubu Electric Power Company participate in the project work of IEA HPP Annex 28.
Japanese heat pump links
HPTCJ Heat Pump & Thermal storage technology Centre of Japan
The Heat Pump & Thermal Storage Technology Center of Japan is a public organization functioning under the auspices of the Ministry of Economy, Trade and Industry. As a national center for heat pumps and thermal storage, HPTCJ promotes the use of thermal storage systems and carries out many projects aimed at improving technology

last update:22.01.2008

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