New Energy Foundation

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=Cartoon Report=
Freezing with Solar Heat
R&D Division, Sanyo Electric Co., Ltd.
Story:Nagamasa Kudo Pictures:Nobuya Akamatsu

ilust
Love for man and the earth
On March 24,1996, Yomiuri Shimbun(Osaka edition) reported with great fanfare that "Sanyo Electric developed a refrigeration device that employs hydrogen alloy and runs on solar heat. "Development of this device was at Sanyo's R&D division based in Hashiritani, Hirakata City, Osaka Prefecture. The departments in charge were the Cooling and Heating Environmental Technology Research Room, Amenity System Research Department, Mechatronics Laboratory, and the New Alloy Research Room, Electronic Chemical Research Department, New Material Laboratory.
On the laboratory wall is the sign that says"we hope to become an existence essential for the people of the world, "Sanyo's pamphlet announces in the beginning that it"loves man and the Earth, "conveying its respect for man and earnest determination to work on environmental protection.

Toward total elimination of CFCs
Chlorofluorocarbons have become a serious threat to the global environment. Certain CFCs that have been used widely as coolant in refrigeration equipment were found to destroy the Earth's ozone layer, increase exposure to hazardous ultraviolet rays, and cause serious impact on tha planet, including rise in skin cancer cases, increase in global temperature, greenhouse effect, and influence on ecosystems. For this reason, CFC production has been stopped by the end of 1995.
To protect the ozone layer, the Vienna Convention was adopted in 1985 and the Montreal Memorandum was signed in 1987. HCFCs,which have been used as alternate CFCs, are expected to be banned by the year 2020 at the 1995 international convention. Technology development eliminating the use of CFCs has become an urgent issue in many areas.
Sanyo's research team at Hirakata had been working on this problem headon since 1977,which is three years before participation in the Sunshine Project.
The project commissioned by NEDO to research into"the use of sola r heat as energy source for refrigeration systems"started in 1989 and was completed in 1992 with first-phase research into water-cooling system. As its second phase, research moved into air/water cooling system and is progressing toward practical use in the year 2000 or thereafter, drawing expectations for wide-ranging applications.
Unlike the conventional electric refrigerator, the system adopts hydrogen-absorbing alloy instead of alternate CFC and runs on natural heat source instead of electricity. It also has replaced the existing "absorption-type refrigerator"and is distinguished for use of hydrogen-absorbing alloy instead of lithium bromide.

Solar heat for refrigerators
Let us explain its basic mechanism with something familiar to us all.
Gardens can be cooled by sprinkling water. This is because heat is removed with evaporation of water. M2H removes heat from its surrounding when hydrogen is released and can even cool a warehouse this way. The released hydrogen is then given a place to go in the next chamber where metal M1 is located. As salt absorbs water even at room temperature, M1 absorbs hydrogen at room temperature. This reaction is completed when either M2H releases as much hydrogen as it can or when M1 absorbs as much hydrogen as it can. This is what is called the "refrigeration process."
Next, let us see the "recycling process." After releasing as much hydrogen as it can, M2 absorbs hydrogen again at room temperature and returns to M2H. After full absorption, application of heat causes M2H to release hydrogen again and return to M1, as when evaporation of water in "miso" soup makes the liquid saltier.
If air and water provides room temperature source and sun provides the heat, a warehouse can be cooled totally with natural energy.
Hydrogen-absorbing alloy conventionally stops releasing hydrogen at around 20 degrees below zero(centigrade). However, Sanyo's research team had been able to improve the alloy configuration to make it release hydrogen at lower temperatures. It was a triumph of the group's idea to combine high-effi-ciency heat exchange system and heat insulation devices.

For inquiries, please contact:
  • Cooling and Heating Environmental Technology Research Room,
    Amenity System Research Department,
    Mechatronics Laboratory

  • New Alloy Research Room,
    Electronic Chemical Research Department,
    New Material Laboratory

    • R&D Division
    Sanyo Electric Co., Ltd.
    1-18-13 Hashiritani, Hirakata City, Osaka 573
    Phone:0720-41-7871
    Fax:0720-41-0302