河北水勘院正定基地地下水源热泵系统热平衡问题分析及对策

Heat balance analysis and countermeasure of groundwater heat pump system of Zhengding in Hebei

为了准确模拟预测河北水勘院正定基地地下水源热泵系统运行期间的地下水渗流场与温度场的变化规律,避免未来地下水源热泵系统运行期间出现的冷热贯通现象与冷热堆积问题,通过总结分析地下水源热泵的应用与模拟研究现状,针对浅层地温能开发与地下水环境模拟中存在的问题,建立了相应的地下水渗流与热量运移三维耦合数值模型,并结合未来地下水源热泵系统的运行工况,预测分析了不同条件下未来地下水源热泵系统的热平衡发展趋势.结果表明:该示范工程按设计方案运行,抽、灌井之间存在热贯通现象及冷堆积问题;提出了当浅层地温能开发存在冷堆积时,在不改变冷热负荷和抽灌井间距时,可采用运行一周期后互换抽水井与回灌井的方案,以有效缓解地下水源热泵工程热贯通现象与冷堆积问题.

To accurately simulate and predict the change of heat balance and avoid heat transfixion and heat accumulation during groundwater heat pump operation in Zhengding,Hebei province,based on the present application status,a three dimensional numerical model between groundwater seepage and thermal transport was established to combine the demonstration project hydrogeology with marine geological exploration. Combined with the design scheme and operation situation,the heat balance development tendency of groundwater heat pump system under different conditions was forecasted and analyzed. The results show that there are heat transfixion and cold accumulation according to the proposed design scheme.When the shallow geothermal energy exploitation causes cold accumulation,exchanging pumping well and recharge well after one year can effectively remit heat transfixion and cold accumulation without changingthe cooling load and the distance between pumping and recharge well.