基于系统优化的岩土热物性确定方法

Determination method for rock-soil thermal properties based on system optimization

针对地埋管地源热泵系统设计中的岩土热物性确定问题,以竖直U形地埋管换热器的管式储热系统DST模型为基础,建立岩土热物性试验系统模型.通过系统模拟出的地埋管换热器进、出水平均温度与实测值的对比,以其差值的平方和为目标函数,利用系统优化的方法,对岩土的综合导热系数和热容量2个参数实施优化,确定出其最优值.通过具体算例,将优化算法确定的热物性参数应用于不同的地埋管换热器模型(有限长线热源模型、柱热源模型、DST模型)中计算埋管平均水温,并与试验结果进行对比,结果表明:应用DST模型确定的热物性参数对应的水温差值的平方和最小,且试验系统模型计算的地埋管换热量模拟值与试验输入值的最大误差为3.11%.

For determining rock-soil thermal properties in the design of ground source heat pump system （GSHPs）, this work presented a system model of rock-soil thermal response test （TRT） based on the duct storage system （DST） model of vertical U-pipes ground heat exchanger （GHE）. As objective function,the temperature difference quadratic sum of the simulated average water temperature in the GHE from the system model and the testing value from the TRT was calculated. And a simulation-optimization approach was proposed for determining the optimal thermal conductivity and the heat capacity of rock-soil. A calculating sample based on TRT was conducted to validate the simulation-optimization approach. After the optimal result was applied in the system model of rock-soil TRT, three groups of simulated average water temperature based on different GHE models （finite line source model, cylinder source model, DST model） were compared with the test values. The result showed that the temperature difference quadratic sum corresponding to the DST model was minimum, and the maximum relative errors of heat transfer rate of GHE between the simulating values from the system model of rock-soil TRT and the test input values were lower than 3.11%.