Abstract:

A coupling prediction model is developed for predicting buried pipes' geothermal field existing water advection and coefficient of performance of ground-source heat pump in this paper. The prediction results were validated by the data from literature. Results show that this model can accurately predict the geothermal field existing water seepage. This validated model was used to study the impact of ground water seepage on the performance of geothermal heat exchangers in ground-source heat pump systems. It was found that whether there is water seepage, the COP would continue to fall when the ground temperature is rising. The COP of the heat pump dropped 49% after 90 days' continuous operation when there is no water seepage. While the COP of heat pump dropped 44.7% when there is seeping water. It indicates that water advection can significantly improve the operation effect of the working unite, and it is also helpful to recover the geothermal field.

Key words: ground source heat pump, water seepage, heat, simulation, performance

摘要：

针对地底渗流现象,开发了存在渗流时地埋管地温场及地源热泵性能耦合预测模型,并利用文献中的实验数据进行了验证,证明所建地埋管群模型与数值计算方法能准确地模拟渗流作用下土壤温度场的变化,可以用于地埋管群土壤温度场的模拟计算。利用模型研究了渗流作用对管群换热过程的影响,发现地下水渗流使得地埋管周围土壤温度场由对称分布产生了拉伸而不再对称;无论是否存在渗流,随着地温温度的升高,机组的COP会持续下降。没有渗流时,连续运行90天后,机组COP下降49.0%,而有渗流时,机组COP下降44.7%。渗流能明显改善机组的运行效果,且渗流也有助于地温场的恢复。

关键词: 地源热泵, 渗流, 热量, 模拟, 性能