Heat transfer model is essential to predicting performance of vertical U-tube ground heat exchanger. Based on reasonable hypothesis a novel 1 -D transient numerical model is built in cylindrical coordinate system for single borehole and multiple boreholes, and the computing algorithm is also given. This model predicts outlet and inlet temperature of U-tube and ground temperature using arbitrary hourly load as inputs. Test data of 3 single-boreholes were used to validate the model's accuracy: comparison of outlet temperature between test and simulation shows that the maximum absolute bias is 0. 8℃. It takes no more than 1 minute to hourly simulate the ground heat exchanger's performance in one-year period. Considering its computing ability, accuracy and speed the authors think the model may be a powerful tool for designing and analyzing borehole heat exchanger of ground source heat pump system.%地下换热器传热模型是地源热泵系统长期运行性能预测的基础.基于合理的简化处理,在柱坐标下建立了一种新的单孔及多孔竖埋U形换热器一维非稳态传热数值模型,并给出了求解算法.该模型基于任意时变冷热负荷,预测换热器进出水温及地温.用3组单孔实测数据进行了验证,出口水温模拟值与实测值最大绝对偏差为0.8℃,说明模型可靠准确.全年逐时动态模拟消耗机时不足1 min.综观计算功能、准确性及快速性,本模型可以作为地源热泵地下换热器设计分析的强有力的工具.
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