Simulation Study On Heat Transfer Performance And Ground Temperature Field Of Vertical Buried Ground Source Heat Pump

With the rapid development of society and technology, the energy problem has become a global problem, the burning of fossil fuels has led to a series of air pollution and environmental deterioration, looking for clean and sustainable energy is a key step to solve the problems of energy and environment. Ground source heat pump technology makes full use of low energy as high energy for purposes of indoor cooling and heating , Ground source heat pump technology,with the features of energy saving, environmental protection,sustainable, gradually into the horizon, recivied more and more personnel favor of industry related people.In this paper, a three-dimensional physical and mathematical model of the coupled heat transfer between the pipe and soil was established based on a project in Nanjing. The thermal response test was carried out to gather the actual operating conditions for the initial conditions of buried pipe heat transfer process simulation, the numerical results and the collected data were compared, results showed that: the operation of 1 days, therelative error between outlet water temperature measured and simulation value is 4.9% in winter,6.4% in summer; running for 24 days, the relative error is 2.3% in winter and 1.6% in summer , in order to verify the accuracy of the model, and the simulation time is longer,the error is small.The factors of buried pipe heat transfer and temperature field are analyzed using this model, during the selection and design of GSHP system, the influence of the physical parameters of soil and buried pipe on the heat transfer performance and the temperature field in the operation of the system are considered, so is the influence of operation time on the heat transfer performance of inlet velocity and sustained operation and the impact of temperature field. The results showed that soil temperature has great influence on the heat exchanger performance and temperature field distribution, the soil temperature of 15?18,which can better meet the requirements of winter and summer running; on the heat transfer performance of thermal conductivity of the soil have obvious effect, soil specific heat decided buried pipe heat effect radius, soil thermal conductivity and specific heat is two an important indicator of the ideal buried pipe laying environment; buried pipe heat transfer increases with the increase of pipe thermal conductivity increases, increase the speed gradually slowed down; promote the increase of inlet velocity on the heat, but the flow rate increases will lead to inadequate and buried tube heat pipe flow resistance increases,so the flow rate increases to a certain value, buried only a small increase in the heat transfer tubes,general 0.6?0.8m/s flow can ensure the import and export of large temperature difference will not affect the overall heat transfer; continuous operation time will lead to a large heat exchange pipe Drop, run continuously for 24 days, reduce the quantity of heat exchange pipe 40%?50%,the radius of thermal effect increases with the increase in running time,running for 30 days, the radius of thermal effect is about 2.0m, the engineering general recommends the use of the 4.0?4.5m tube spacing.The influences of factors on heat exchanger performance and temperature field distribution was studied in this paper to provide guidance and theoretical basis for actual engineering during the choose of site, design and operation management of GSHP system...