Numerical evaluation of the effects of groundwater flow on borehole heat exchanger arrays
Numerical evaluation of the effects of groundwater flow on borehole heat exchanger arrays
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DOI：
10.1016/j.renene.2012.10.028
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发表时间：
2013-04
期刊：
影响因子：
8.7
通讯作者：
J. Choi;Joonsang Park;Seung-Rae Lee
中科院分区：
文献类型：
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作者：
J. Choi;Joonsang Park;Seung-Rae Lee
采用二维热传导-对流耦合模型研究了地下水流方向和流速对不同类型埋管换热器阵列性能的影响。使用三种类型的阵列（矩形、L型和单线）模拟了15年的加热操作。结果表明，地下水流方向和流速对L型和单线阵（非正方形矩形阵）的性能有显著影响。当Peclet数的特征长度被假定为单位值时，Peclet数小于0.05（即在本研究中小于1 m/yr的低流速）对系统性能的影响可以忽略不计，无论阵列类型或流向如何。地下水流下游地下的蓄冷似乎与流体温度随水流方向的变化有关。年热容量的比较表明，根据流动方向的不同，可能会出现高达13%的差异。这表明，在设计最佳BHE阵列时，考虑地下水流的方向和速率可能是重要的，特别是对于非正方形矩形阵列。
The effects of both direction and rate of groundwater flow on the performance of various types of borehole heat exchanger (BHE) arrays are examined using a two-dimensional coupled heat conduction–advection model. The heating operations were simulated over a period of 15 yrs using three types of arrays: rectangular, L-type, and single line. The results show that the performance of the L-type and single line-type arrays (non-square rectangular arrays) was noticeably influenced by the direction of groundwater flow as well as the flow rate. When the characteristic length of Peclet number was assumed to be a unit value, the Peclet number less than 0.05 (i.e. low flow rates less than 1 m/yr in this study) was found to have negligible effects on the performance of the system, regardless of the array type or flow direction. The cold accumulation in the ground downstream of the groundwater flow seems to be related to the variation of the fluid temperature associated with the flow direction. The comparison of annual heat capacity shows that up to 13% difference can occur depending on the flow direction. This suggests that the consideration of both direction and rate of groundwater flow may be important in designing the optimal BHE arrays, particularly for the non-square rectangular arrays.