Numerical Simulation Of Energy Pile Heat Transfer And Thermal Storage

Energy pipe is a special ground source heat pump technology which combined the traditional ground source heat pump system with pile foundation,Energy pipe technology with two major technical advantages which are large heat transfer cross section of pile foundation and concrete materials with good thermal conductivity.Compared with the traditional heat exchanger,energy pipe with higher efficiency,better heat transfer performance.Energy pile construction is synchronized with the building pile foundation construction,and the heat exchanger is embedded in the pile foundation,reduce drilling cost and backfill material,which reflects its economic advantage.In the land of the city underground space utilization,application of energy pile technology reflects its broad market prospects.Although the energy pile technology has a lot of advantages but its large-scale application and popularization still have two problems,energy pile heat transfer performance evaluation is not comprehensive enough,on the other hand,the energy pile thermal storage system under different injection thermodynamic heat storage effect and structure of the corresponding response lack of research.In view of the above two problems,this paper uses numerical analysis method to study the heat transfer performance,thermal storage effect and structural thermodynamic response of energy pile.The main contents of this paper are as follows:(1)The process of energy pile system operation is a process of multi field coupling,including the flow and temperature change in the heat exchanger,pile body and soil temperature field and structure field changes,the pile foundation seepage environmental impact,this paper based on the previous research of the establishment of energy double pile thermal coupling and fluid solid heat coupling mathematical model,the feasibility and correctness of the mathematical model and the coupling mode built through the model test of previous.(2)The numerical calculation of the full scale energy pile geometry model by two heat coupling mathematical model of energy pile up,analyzes the influence of pile energy heat transfer performance factors such as the refrigerant injection temperature,refrigerant flow,material of pile,the pile of rock and soil,thermal conductivity and heat exchanger materials the branch spacing,initial temperature,heat exchanger diameter and wall thickness,pile diameter and pile depth,operation mode,groundwater flow velocity on the heat transfer performance of energy pile,which provides reference for the design of energy pile foundation.(3)The use of heat energy pile established solid coupling mathematical model for numerical simulation of energy pile thermal storage system,using four different injection schemes of energy pile loaded and considering the mechanical structure of pile foundation load,analysis of different injection schemes of energy storage change of temperature field in the system,analysis of single group pile under load of pile pile and soil stress field change,and provide a theoretical basis for the optimization of system operation for energy storage pile.