Influence Of Groundwater Seepage On Heat Transfer Performance Of Ground Heat Exchanger

Ground source heat pump?GSHP?technology is a kind of renewable energy technology,which is the most promising energy saving and environmental protection technology in the 21th Century.And the key to the promotion of ground source heat pump technology is the heat transfer problem of the ground heat exchanger?GHE?.This paper focused on the influence of groundwater seepage on heat transfer performance of GHE,and regarded the inlet and outlet temperature of the fluid in tube as the focus of study.The ground heat transfer efficiency?GTE?coefficient was introduced as the evaluation parameters to make quantitative analysis on the heat transfer performance of GHE.The main contents were as follows:?1?The mathematical and physical models of a vertical U-tube GHE under two kinds of heat transfer manners?considering the groundwater seepage or not?were established,in which the modes were based on real condition.The finite element analysis software was used as the dynamic numerical simulation platform to analyze the influence of many factors on the GTE,the results showed that the GTE could be improved by increasing the thermal conductivity of the backfill material,increasing the branch pipe spacing or When the seepage velocity is 10^-6m/s magnitude,the heat transfer efficiency of the GHE can be improved in the area where the groundwater seepage velocity is large;Choosing the inlet velocity of 0.6⁰.8m/s was more favorable to the heat transfer of the GHE;When the groundwater seepage temperature is 15?or the inlet temperature is 40?,the heat transfer capacity of the GHE is the strongest.?2?By comparing the difference of the heat transfer performance of GHE under the condition of groundwater seepage or not,found that groundwater seepage could effectively enhances GTE,and the running time was longer,the influence of groundwater seepage on heat transfer ability of GHE was more obvious.Therefore,under the premise of meeting the heat transfer load,considering the seepage of groundwater could reduce the number of pipe or the drilling depth,so as to reduce the initial investment of GHE.