基于地埋管换热器热响应测试的土壤热物性参数估算方法

Estimation method of soil thermal physical parameters based on thermal response test of ground heat exchangers

根据实测地埋管换热器进出水温度和流量,分别用线热源解析模型、柱热源解析模型和一维数值模型估算土壤的导热系数、孔内热阻和单位体积热容。介绍了二三参数估算法,三参数估算法可同时估算导热系数、孔内热阻和单位体积热容,但计算时间太长,对计算机的内存要求也较高;二参数估算法对导热系数和孔内热阻进行寻优搜索,单位体积热容利用关联式计算,结果合理,计算时间较短。基于二参数估算法结果显示,一维数值模型的结果更接近实际值。

According to the measured inlet and outlet water temperature and flow rates, estimates the thermal conductivity of soil, thermal resistance in hole and heat capacity per unit volume using linear and cylindrical heat source analytical models and one-dimensional numerical model respectively. Presents two and three-parameter estimation methods. Three-parameter estimation method can estimate the thermal conductivity, thermal resistance in hole and heat capacity per unit volume at the same time, but the calculation time is too long, and the requirement of the computer memory is higher. Two-parameter estimation method can obtain reasonable results through searching thermal conductivity and thermal resistance in hole, the heat capacity per unit volume can be obtained by using the correlative equation, and the calculation time is less. The results based on the two parameter estimation method show that the result using one-dimensional numerical model is closer to the actual value.