1990 Fiscal Year Final Research Report Summary
Direct Solar Thermal Energy Storage Using a Semitransparent Phase Change Material
| Project/Area Number |
01550729
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
化学工学
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| Research Institution | Gifu University |
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Principal Investigator |
NISHIMURA Makoto Gifu Univ., Fac. Eng., Professor, 工学部, 教授 (10021627)
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| Co-Investigator(Kenkyū-buntansha) |
BANDO Yoshiyuki Gifu Univ., Fac. Eng., Assoc. Professor, 工学部, 助教授 (60144002)
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| Project Period (FY) |
1989 – 1990
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| Keywords | Heat storage / Latent heat storage / Phase change material / Solar thermal energy / Volume heat trap |
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| Research Abstract |
The latent heat storage of a volume heat trap (VHT) type was proposed as a new passive system of solar thermal energy storage, in which a plane layer of a semitransparent phase change material (PCM) is directly heated and melted by the sun. The performance was investigated in the indoor and the outdoor experiments and analyzed theoretically. Those of the latent heat storage of surface heat trap (SHT) type and the sensible heat storage of VHT type were examined in parallel. Paraffin wax was used as a PCM and the time changes of temperature distributions in the collector during heat storage weremeasured. The tilt angle of the collector and the thickness of PCM were varied. In the theoretical analysis, the basic equations were derived by assuming the two-dimensional fluid flow and heat transfer and by applying the concept of overall specific heat, and were solved numerically. The effects of the tilt angle and the thickness of PCM on the time changes of temperature distribution and heat storage efficiency were discussed. As a result, the following conclusions were obtained.
1) The calculated results reasonably expressed the tendencies of the experimental data so that the present theoretical analysis was considered to be valid.
2) The latent heat storage of VHT type was superior in performance to the latent heat storage of SHT type and the sensible heat storage of VHT type.
3) In the latent heat storage of VHT type, the internal heating and the heat and fluid flow by natural convection affected the characteristics of heat storage.
4) In the outdoor experiments, the most suitable tilt angle was found to be solar incidence angle at the time of culmination.
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