Numerical Simulation Analysis Of Dual U-tube Earth Buried Heat Exchanger In Winter And Summer

With the development of economy and the improvement of productivity,people enjoy the superior life brought about by the rapid development of material information.At the same time,the energy shortages that can be used become more and more obvious.The road to sustainable development is of global importance.The development strategy.The energy consumption related to HVAC of our country's civil buildings accounts for more than 55% of the energy consumption of buildings.Therefore,in the current situation,ground-source heat pump air-conditioning systems with energy-saving,environmental-friendly,and sustainable characteristics gradually come to our attention.Pay attention.Geothermal heat exchanger is very important for ground source heat pump air conditioning system.Its heat transfer performance will affect the work efficiency and operation of the entire heat pump system.Therefore,studying geothermal heat exchanger has become a more widely used ground source.Heat pump air conditioning system is an important research topic.The purpose and significance of the research in this paper is to provide reference for the actual design of ground source heat pump through the data and conclusions obtained through numerical simulation,and to contribute to the sustainable development of energy.In this paper,the underground vertical double U-shaped underground heat exchanger is taken as the research object,combined with engineering examples and related literatures,to conduct comparative analysis of continuous and intermittent operation in winter and summer,mainly to perform the following work:Firstly,on the basis of introducing the heat pump heat transfer mode of the ground source,the heat transfer process of the vertical double U underground pipe is analyzed,and the effect of the heat transfer model of the ground pipe on the thermal properties of the soil is studied.Secondly,using GAMBIT,FLUENT software to establish a vertical double U-shaped underground heat transfer model;Finally,the CFD software was used to simulate the 90-day continuous and intermittent operating conditions in winter and summer,and the distribution of the temperature field in the ground tube and surrounding soil and the vertical double U-tube heat exchanger were obtained.The role radius increases with the passage of time and the growth rate becomes slower,and through the change in the unit well depth heat transfer over time,the value of the heat transfer amount at each time and the regularity of the change are obtained,and geothermal is also obtained.The temperature of the water along the pipe running in different periods has been changed linearly,and the temperature difference between the inlet and outlet of the geothermal pipe has changed after the system has been running for different periods of time.Several suggestions for specific engineering design have been put forward.For example,in the actual engineering design,the radius of the heat pump system operation under corresponding conditions can be multiplied by 2 as the optimal shaft spacing for ensuring continuous operation of the heat pump system;the temperature of the water is not caused due to thermal interference between the legs.Changes along the exit can be added without insulating layer in the exit section;during the operation of the heat pump system,only the soil temperature at the top and bottom of the geothermal heat pipe varies greatly.Therefore,when designing the ground source heat pump system,the geothermal heat pipe is surrounded.The bottom and top areas focus on the soil and so on.