This paper proposes an optimum operation method for open loop ground heat exchangers. A series of TRTs and artificial heating/cooling operations was carried out with 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 & CFD 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 ~ 500m. In the future, an open loop ground heat exchanger system adopting the optimum operation with variation in the ground temperature will be used in practice.
Keywords. Open-Loop Ground heat exchanger; Standing column well; Logarithmic mean temperature difference; Entering water temperature; Thermal response test
How to cite this article
Choi, H., Park, S., Pham, K.L.N., Ryu, H. and Choi, H. (2014). 'A study on effective energy use of the open loop ground heat exchanger using underground temperature gradient'. SET Proceedings, 13, pp. 1-9. https://doi.org/10.65582/set.2014.015
