著者

Salsuwanda SELAMAT Akio MIYARA Keishi KARIYA

出版者

公益社団法人 日本冷凍空調学会

雑誌

日本冷凍空調学会論文集 (ISSN:13444905)

巻号頁・発行日

pp.15-18RE_OA, (Released:2015-08-31)

参考文献数

14

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Horizontal ground heat exchanger in ground source heat pump systems is susceptible to ground surface variations thus affecting its thermal performance. However, this configuration is desirable due to low installation costs as it mainly involved burying pipes in shallow trenches. The optimization of horizontal ground heat exchanger was investigated by simulating a cross section of the ground containing a single unit of slinky-loops. The analysis shows that although trench depth increased by one third in vertical orientation, there was no significant improvement on thermal performance compared to horizontal orientation. Unless land area is limited then it is suggested that loops are installed in vertical orientation. When the material used as ground heat exchanger was copper pipe, heat exchange rate improved by 20% compared to conventional HDPE pipe. As expected, ground thermal resistance has a limiting effect on thermal performance although the pipe was changed to a material with thermal conductivity of over 800 times higher. The effect of distributing the flow into a group of loops in parallel was also examined. Thermal performance increases as more heat transfer area was provided in parallel loops. The spacing between adjacent loops was studied to elucidate heat interference in parallel loops operation.