地源热泵岩土热响应测试影响因素分析

Analysis of Influencing Factors on Thermal Response Test in Ground Source Heat Pump

建立了地源热泵岩土热物性现场测试系统的三维数值模型,基于所建数值模型分析了测试时间、舍弃初始小时数、钻孔半径、岩土体初始温度、加热器输入功率等因素对岩土热响应测试结果的影响。研究结果表明:对于柱热源模型,随着钻孔尺寸的增大,辨识得到的热导率越小;采用参数估计法作为辨识方法时,岩土初始温度的测试精度对辨识结果有较大影响。测试得到的热导率有6%~18%的偏差。

A three dimensional numerical model of ground source heat pump system was established, and the effects of testing time, starting time, borehole radius, initial ground temperature and heat injection rate on identified thermal conductivity of the deep ground soil were analyzed based on the numerical model. The simulation results showed that the identified thermal conductivity decreases with an increase in borehole radius based on column-source method. For parameter estimation, the measuring accuracy of the initial temperature of the deep ground soil has greater effect on identified thermal conductivity. The deviations of measured heat conductivities are within 6%~18%.