土壤冻结作用下地埋管换热器的传热特性

Heat transfer characteristics of ground heat exchangers under soil freezing

以哈尔滨的土壤质地为研究对象,基于相似理论自行搭建了地埋管换热器低温取热工况实验台,研究了不同土壤初始含水量、孔隙率对埋管侧土壤冻结范围、埋管自身换热性能及热泵机组COP的影响。研究结果表明:土壤初始含水量在0~40%范围内时,含水量越大,埋管侧土壤冻结范围越小,换热器换热性能越好,以含水量由0增大到10%最为明显;土壤初始孔隙率由0.16增大到0.38时,换热器换热性能有明显提升,孔隙率由0.38增大到0.47时,对换热器换热性能影响较小;土壤初始含水量为40%、孔隙率为0.47时,地埋管地源热泵机组COP可达3.19。

Taking the soil texture of Harbin as the research object,based on the similarity theory,sets up an experimental platform for low temperature heating of ground heat exchangers,and studies the effects of different initial soil moisture content and porosity on soil freezing range,heat transfer performance of buried pipes and COP of heat pump units.The results show that when the initial soil moisture content is in the range of 0 to 40%,the higher the moisture content,the smaller the freezing range of soil on the buried pipe side,and the better the heat transfer performance of the heat exchanger,especially when the moisture content increases from 0 to 10%.When the initial porosity of soil increases from 0.16 to 0.38,the heat transfer performance of the heat exchanger is obviously improved,and when the porosity increases from 0.38 to 0.47,it has little effect on the heat transfer performance of the heat exchanger.When the initial soil moisture content is 40%and the porosity is 0.47,the COP of the ground-source heat pump unit can reach 3.19.