热屏障井对地下水源热泵换热影响模拟

对于场地受限的地下水源热泵项目，随着系统运行时间的增加易引发热贯通现象进而降低机组运行效率。地下水源热泵设计中，在抽灌水井连线间布设热屏障井可改变地下水流场，降低热量在抽灌井间的运移速度，有利于延长热贯通发生时间并缓解热贯通程度。通过构建地下水换热模型，模拟计算夏季制冷工况条件下36组热泵运行场景，分析了热屏障井的位置，过滤管长度及回灌量对热贯通和含水层温度场的影响规律。结果表明:热屏障井回灌量的增加有利于提升热屏障效果，但提升幅度随回灌量的增加逐渐减弱；最大水位降深值随着热屏障井回灌量的增加呈线性增长；增加热屏障井滤管长度可提升热屏障效果，提升效果随屏障井回灌量的增加逐渐增强。通过模型多周期、长时间模拟计算发现，热屏障井的运行可促使回灌的冷热量集中在回灌井一侧，对于采用冬夏季抽灌井交换运行模式的热泵系统，可充分利用含水层储能，提升机组运行效率。

Simulation study on the effect of thermal barrier well on the heat transfer of groundwater heat pump

GWHP system is easy to cause the thermal breakthrough which will reduce the operation efficiency,when the site area is small.In the design of GWHP,by setting up a thermal barrier well between the pumping and recharging well can reduce the heat transfer speed between pumping and recharging well,which is conducive to prolonging the occurrence time of thermal breakthrough.36 groups of GWHP operation scenarios under the cooling condition are simulated through heat transfer model,and the influence of the location,structure and recharge quantity of the thermal barrier well on the thermal breakthrough and the aquifer’s temperature field are analyzed.The results show that the increase of recharge quantity of the thermal barrier well is conducive to improving the thermal barrier effect,but the degree of improvement decreases with the increase of recharge quantity.At the same time,with the increase of recharge quantity,the maximum drawdown will increase linearly.The location of the thermal barrier well has little influence on the aquifer temperature field and the closer the barrier well is to the recharging well,the later the thermal breakthrough time will be.Increasing the length of the filter tube in the heat barrier well can improve the thermal barrier effect,and the effect of the thermal barrier is gradually enhanced with the increase of the recharge quantity.In addition,through the long-time simulation of model,it is found that the operation of the heat barrier well can concentrate the energy near the recharging well.When the GWHP adopts the exchange operation mode of pumping and recharging well,it can make full use of the aquifer energy storage and improve the operation efficiency of heat pump.