竖直埋管换热器热响应半径简化计算方法

THE SIMPLIFIED CALCULATON METHOD OF THE THERMAL RESPONSE RADIUS FOR VERTICAL BOREHOLE HEAT EXCHANGERS

基于半无限空间均匀介质线热源传热模型,在大量数值计算分析基础上,提出竖直埋管换热器热响应半径的简化计算方法。计算方法考虑了土壤热物性、系统运行时间和钻孔布置方式等因素。计算结果表明,对于钻孔单排、双排和多排布置情况下,本文方法的计算结果与理论解之间最大相对误差分别为3.51%、2.96%和2.76%,满足工程要求。针对实际地源热泵系统运行时常根据需要采用昼夜和季节间歇运行工况的情况,给出系统运行时间的计算方法。为便于工程应用,分别计算单排、双排和多排(三排以上)钻孔布置方式下不同岩土介质竖直埋管换热器热响应半径随时间的变化曲线,绘制出计算图表,为工程应用提供理论依据和方法。

The simplified calculation method of thermal response radius for vertical borehole heat exchangers was proposed by a large number of numerical analysis with the semi-infinite homogeneous medium line source heat transfer model in this paper. The soil thermal physical properties, system running time and borehole arrangements is considered in the calculation method. The calculation results showed that the maximum relative errors between the method and analytical solutions were 3.15%, 2.96% and 2.76% respectively in the case of a single row, double rows and more than three rows drilling layout which satisfied the engineering demand. The calculation method of system running time was suggested in view of the operation mode of day and night and seasonal intermittent for ground-source heat pump system. The graph of thermal response radius for vertical borehole heat exchangers along with running time was presented with different soil media of a single row, double rows and more than three rows drilling layout in this paper which provided theoretic and method of the engineering application.