This study was carried out with the purpose to estimate the exhaust air temperature changed by passing through the pipe of the soil-air heat exchange system. It was clarified that the exhaust air temperature could be calculated using the established mathematical model under the boundary conditions which were surface soil temperature, soil temperature at the depths and the intake air temperature. Then, the results of the simulation were discussed in comparison with the experiments.
As the result, the values of which were the exhaust air temperature, the inner wall temperature of the heat exchange pipe and soil temperature obtained from the simulation were agreed with the experimental values. It was concluded that the mathematical model was useful for the soil-air heat exchange system.
As for the technical problem of soil-air heat exchange system, the effects of materials and the length of heat exchange pipe were, furthermore, discussed using the above model. Among them, it was became obvious that the function of the soil-air heat exchange system, even using the pipe with the low thermal conductivity, was depending on the method that made the contact thermal resistance low when the pipe was buried, and was not so largely depending on the materials chosen. Moreover, it was concluded from the result of simulation that the horizontal buried pipe was not necessary so long, but had better have a unit made of about 10m length pipe.
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