土壤分层对U形地埋管换热器换热能效特性的影响
Heat transfer energy efficiency characteristics of U-tube ground heat exchangers in stratified soil
摘要：
基于土壤分层特点，引入地埋管换热器能效系数作为换热特性评价指标，模拟分析了无渗流情况下土壤径向与轴向分层对地埋管换热器换热特性的影响。结果表明，回填材料导热性能、不同导热系数土壤层位置及厚度对地埋管换热器的换热特性均有一定影响；增强回填材料的导热性能在运行初期可削弱或抵消热堆积作用，但运行时间一长，会增大热短路效应；高导热系数土壤层位于钻井上部时可增强区段能效系数；增大高导热系数土壤层厚度可增强地埋管换热器总的换热能效。
Abstract：
Based on soil stratification, introduces an energy efficiency coefficient index to evaluate heat transfer characteristics of ground heat exchangers (GHEs). By dynamic simulation, investigates the impact of soil stratification in the radial direction and axial direction on the heat transfer characteristics of GHEs. The results show that the thermal conductivity of backfill material, and position and thickness of soil layers with different thermal conductivities have impact on the heat transfer characteristics of GHEs. The backfill material with higher thermal conductivity can weaken or counteract the heat accumulation effect in early stage but may strengthen short circuit of heat in later time. The section efficiency coefficient can be improved when the soil layer with higher thermal conductivity is on the upper part of borehole. The energy efficiency may increase with the thickness of the soil layer with high thermal conductivity.
Keywords:U-tubegroundheatexchanger,soilstratification,energyefficiencycoefficient,backfillmaterial,thermalconductivity,position,thickness