| Project/Area Number |
01550461
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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 |
建築環境・環境工学
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| Research Institution | Faculty of Engineering, Kagoshima University |
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Principal Investigator |
AKASAKA Hiroshi Kagoshima Univ. Professor, 工学部, 教授 (20094112)
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| Co-Investigator(Kenkyū-buntansha) |
OHARA Satoshi Miyakonojyo College Research Associate of Technology, 建築学科, 助手 (60214219)
KUROKI Soichro Kagoshima Univ. Research Associate, 工学部, 助手 (30094139)
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| Project Period (FY) |
1989 – 1990
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| Project Status |
Completed (Fiscal Year 1990)
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| Budget Amount *help |
¥2,400,000 (Direct Cost: ¥2,400,000)
Fiscal Year 1990: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1989: ¥2,000,000 (Direct Cost: ¥2,000,000)
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| Keywords | wooden house / attic ventilation / amount of air change / heat exhausting effect / k-epsilon model / k-εモデル |
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| Research Abstract |
Attic air temperature of wooden houses usually rises more than 50 ^ﾟC during daytime in the summer season, and this causes a temperature rise in the rooms underneath the attic space. The common countermeasure for this problem is ventilation of attic space. Especially, forced ventilation of attic space with fan is expected to be effective on heat exhaust and lowering the temperature of the space. So this effect was examined quantitatively by the field measurements of two individual wooden houses (One is 2 x 4, and the other was constructed by Japanese traditional method) in Kagoshima City from 1989 to 1990. Based upon the measurements of attic air temperature and amount of air change of attic space as well as air temperature of the ceiling underneath the attic space, the following results were obtained :
1. Fan is effective when attic space is air tight and amount of natural air change is small. When the Amount of natural air change exceeds 4 (times/h), fan is no more effective on lowering attic temperature.
2. Even if attic space is well ventilated, attic temperature is higher than outdoor temperature by 3 to 5 ^ﾟC. To lower attic temperature to outdoor temperature, roof insulation should be necessary. The thickness of the insulation should be decided taking into account intensity of solar radiation.
In addition to the field measurements, K- epsilon turbulence model was introduced to analyze attic air distribution. Both isothermal and non-isothermal situations with forced ventilation were simulated. The influences of inlet and outlet locations and their sizes
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