Study On The Influencing Factors Of Water Temperature Of Buried Pipes And The Change Of Soil Temperature

With the development of industry,more and more attention has been paid to the energy problem.Ground source heat pump(GSHP)is an engineering technology that takes heat from the soil in winter and accumulates heat to the soil in summer.This system makes full use of renewable energy and has the advantages of energy conservation and environmental protection.The ground source heat pump uses the buried pipe to exchange heat with the surrounding soil.The heat exchange efficiency is affected by many factors,which have mutual influence.In some areas,the amount of heat removed from the soil in winter is much more than the amount of heat stored in the soil in summer,so it will cause the imbalance of the soil cold and heat.If the heat pump operates for a long time,it will cause the cold accumulation of the ground,which will affect the operation efficiency of the heat pump system.The establishment of the relationship between the water temperature of the buried pipe and the soil temperature can reflect the change of the soil temperature through the water temperature of the buried pipe,predict the soil temperature,reduce the accumulation of soil heat and cold,which has theoretical significance and practical value for the operation regulation of the system and energy conservation and emission reduction.In this paper,Gambit software is used to build the system model of the ground heat exchanger and divide the grid.Then FLUENT software is used to set up the boundary conditions of the model and build the heat exchange model for simulation.Through analysis,the influencing factors of the outlet water temperature of the ground heat exchanger and the influence degree of each factor are summarized.Summer conditions: the larger the flow velocity of the circulating medium,the higher the inlet temperature of the circulating medium and the higher the initial soil temperature,the change of these conditions will increase the outlet water temperature;the higher the thermal conductivity of the soil and backfill material,the lower the outlet water temperature.Winter conditions: the higher the flow velocity of the circulating medium is,the lower the outlet temperature is;the higher the inlet temperature of the circulating medium is,the higher the initial temperature of the soil is,the greater the thermal conductivity of the soil is,and the higher the thermal conductivity of the backfill material is,the change of these conditions will increase the outlet temperature.In order to study the relationship between the operation of the ground pipe heat exchanger and the surrounding soil temperature,this paper uses the simulation software to simulate and analyze the operating conditions of the ground pipe heat exchanger system in different seasons for 60 days,90 days and 150 days.The results show that: the soil temperature around the borehole presents the logarithmic distribution rule in different operating days.According to the knowledge of heat transfer,the relationship between the outlet water temperature of buried pipe and the soil temperature can be established.