地下水源热泵抽灌井群优化布置

为提高地下水源热泵效率,避免在回灌与抽水过程中发生热贯通,研究地下水源热泵系统井群的合理布置形式。基于COMSOL Multiphysics软件,建立地下水源热泵抽灌系统的三维模型,模拟抽灌井在对齐型、交错型和叉排型3种不同布置形式以及不同井距下抽水井水温变化情况,根据热贯通发生的程度,选取井群布置的最优形式。结果表明:无论井距如何变化,中心井温度变化始终最大且最明显,即所受热贯通影响最大;在相同的布置形式下,抽灌井之间距离越大,抽水井水温变化幅度越小,发生热贯通的程度越轻;在系统运行期间抽灌井采用对齐型布置方式时,热贯通发生时间最晚且影响最小,且井距取100 m时在2种工况下4号井水温变化均为0.03 K,5号井分别升高0.07 K和降低0.06 K,6号井则分别升高0.02 K和降低0.03 K,故采用100 m为宜。

Optimal Layout of Pumping and Recharging Wells for Ground-source Heat Pump

The reasonable layout of well group for ground-source heat pump system is studied in the purpose of improving the efficiency of ground-source heat pump and in the meantime avoiding heat penetration during refilling and pumping. A 3D model of the pumping and recharging system for ground-source heat pump is established using COMSOL Multiphysics software to simulate the water temperature in wells of three different layouts (aligned, staggered, and cross-row layouts) with different well spacings. The optimal layout of well group is selected according to the degree of heat penetration. Results demonstrate that: no matter how the well spacing changes, the temperature in the central well changes the most drastic, subject the most to thermal penetration; in the same layout, a wider spacing between pumping wells results in a smaller change of water temperature and a slighter heat penetration. When the pumping and recharging wells are arranged in alignment, heat penetration during the operation of the system occurs the latest with the least impact. When the well spacing is 100 m, the water temperature of well No.4 under both working conditions changed by 0.03 K, whereas that in well No.5 climbed by 0.07 K and dropped by 0.06 K respectively in the two working conditions, and well No.6 raise by 0.02 K and fell by 0.03 K, respectively. In conclusion, a spacing of 100m is recommended to be the optimal.