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http://dx.doi.org/10.6110/KJACR.2014.26.9.401

A Study on Effective Energy Use of the Open Type Ground Heat Exchanger Using Underground Temperature Gradient  

Ryu, Hyungkyou (Technology Research and Development Institute, Daelim Industrial Co., Ltd.)
Chung, Minho (Technology Research and Development Institute, Daelim Industrial Co., Ltd.)
Lee, Byungseok (Technology Research and Development Institute, Daelim Industrial Co., Ltd.)
Rhew, Hyojun (Daelim Information and Service Co., Ltd.)
Choi, Hyunjun (School of Civil, Environmental and Architectural. Engineering, Korea University)
Choi, Hangseok (School of Civil, Environmental and Architectural. Engineering, Korea University)
Publication Information
Korean Journal of Air-Conditioning and Refrigeration Engineering / v.26, no.9, 2014 , pp. 401-408 More about this Journal
Abstract
This paper proposes an optimum operation method for open type ground heat exchangers. A series of TRTs and artificial heating/cooling operations were carried out while monitoring temperature in the hole of SCW. The ground temperature naturally increases with depth, but a switch between the cooling/heating mode results in a change in the distribution of ground temperature. The effect of the mode change was evaluated by performing LMTD and COMSOL multiphysics analysis for a reduced model with the depth of 150 m. As a result, in the cooling mode, the upstream operation is more efficient than the downstream operation and reduces EWT by $2.26^{\circ}C$. On the other hand, in the heating mode, the downstream operation is advantageous over the upstream operation and increases EWT by $3.19^{\circ}C$. The merit of the optimum operation will be enhanced for the typical dimension of SCW with a depth of 400~500 m. In the future, an open type ground heat exchanger system adopting the optimum operation with variation in the ground temperature will be used in practice.
Keywords
Open type ground heat exchanger; SCW; LMTD; ,EWT; LWT; TRT;
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