| Title |
A Study on Effective Energy Use of the Open Type Ground Heat Exchanger Using Underground Temperature Gradient |
| Authors |
류형규(Hyungkyou Ryu) ; 정민호(Minho Chung) ; 이병석(Byungseok Lee) ; 류효준(Hyojun Rhew) ; 최현준(Hyunjun Choi) ; 최항석(Hangseok Choi) |
| DOI |
http://dx.doi.org/10.6110/KJACR.2014.26.9.401 |
| Keywords |
개방형 지중열교환기 ; 스탠딩컬럼웰 ; 대수평균온도차 ; 히트펌프 입구온도 ; 히트펌프 출구온도 ; 열응답 시험 Open type ground heat exchanger ; SCW ; LMTD ; EWT ; LWT ; TRT |
| 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℃. On the other hand, in the heating mode, the downstream operation is advantageous over the upstream operation and increases EWT by 3.19℃. 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. |