| Project/Area Number |
63550430
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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 | KYUSHU UNIVERSITY |
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Principal Investigator |
HAYASHI Tetsuo KYUSHU UNIVERSITY, GRADUATE SCHOOL OF ENGINEERING SCIENCES, ASSOCIATE PROFESSOR, 総合理工学研究科, 助教授 (40150502)
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| Co-Investigator(Kenkyū-buntansha) |
SHIOTSUKI Yoshitaka KYUSHU UNIVERSITY, GRADUATE SCHOOL OF ENGINEERING SCIENCES, RESEARCH ASSISTANT, 総合理工学研究科, 助手 (40150487)
KATAYAMA Tadahisa KYUSHU UNIVERSITY, GRADUATE SCHOOL OF ENGINEERING SCIENCES, PROFESSOR, 総合理工学研究科, 教授 (80017938)
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| Project Period (FY) |
1988 – 1989
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| Project Status |
Completed (Fiscal Year 1989)
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| Budget Amount *help |
¥2,400,000 (Direct Cost: ¥2,400,000)
Fiscal Year 1989: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1988: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Keywords | Heat Transfer on and under Ground / Moisture Movement / Heat Balance at the Ground Surface / Water Evaporation / Simulation / Thermal Properties / Water Content / Long-Term Measurement |
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| Research Abstract |
Long-term Observation of vertical temperature distribution and surface heat flux of the ground has been carried out through two years. The ground is covered with five different kind of materials; bare soil, lawn, concrete pavement, asphalt pavement and permeable asphalt pavement. The Observation includes the data acquisition of weather and water content of soil.
The results of the long-term Observation show the daily average surface temperatures of the the concrete and the asphalt pavement are over 40ﾟC in summer. The daily average surface temperatures of the bare soil and the lawn are lower than those of the concrete and the asphalt pavement by from 7 to 10ﾟC in the same season. The underground temperatures of the bare soil and the lawn at the depth of 80cm are always lower than those of the concrete and the asphalt pavement by from 3 to 5ﾟC through a year. The water content of the soil under the concrete and the asphalt pavement is high because of the suppression of water evaporation
… More
at the surface.
The thermal conductivity, volumetric specific heat and electric resistance of the soil were measured according to the variation of the water content. The thermal conductivity of the soil under wet condition has as two times large value as that under dry condition.
Two types of simulation model are examined to predict the thermal performance of the ground. One exactly considers the moisture movement in the ground, and the other simply takes the effect of water evaporation at the surface into consideration. In the former simulation model, called Model A, moisture in the ground moves according to the gradient of water content and thermal properties of the soil also vary according to the water content. The latter model, called Model B, uses evaporation ratio to calculate the water evaporation at the surface and thermal properties are constant. The comparison of the measured and the calculated values shows Model A is more accurate than Model B in the viewpoint of the reproducing heat transfer phenomenon on and under the ground. Model B, however, has enough accuracy to predict the heat transfer on and under the ground. Less
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