| In recent years,China’s economy continues to develop,people are increasingly high quality of living,building air-conditioning system(heating and cooling)is necessary for people’s lives,but this part of the total energy consumption accounted for the total energy consumption 25% to 30%.In China,most of the region mainly to coal energy as a heating resource,coal energy in the combustion process will produce a large number of toxic and harmful gases,to bring a series of environmental problems.In a variety of new and renewable sources of energy,ground source heat pump systems are a sustainable,environmentally friendly energy system that utilizes geothermal energy heating / cooling construction to meet green building design requirements.Earth’s surface contains the huge potential of stored geothermal energy,ground source heat pump technology is to take full advantage of this energy for heating and cooling a building energy-saving technology.Since the 1990 s,ground source heat pump technology has been from around the world has been vigorously developed and widely used.Although the ground source heat pump with economic,energy saving,green and many other advantages,but not perfect,the main manifestations in three aspects: 1.The project began to invest high capital 2.Unreasonable layout takes up the underground space,3 The wrong way to pollute the groundwater.This paper summarizes the current ground source heat pump technology based on the proposed energy pile technology.The energy pile technology embeds the heat transfer tubes in the concrete piles,and connects the heat exchangers through the inlet and outlet pipes to realize the heat transfer between the energy pile and the surrounding soil.The implementation of the technology to reduce the ground source heat pump system in the drilling links,saving land,reduce project cost.The main results of this paper are as follows:(1)This paper summarizes the research status of energy pile technology both at home and abroad,and introduces the main problems and research value of energy pile.(2)The heat transfer theory between heat exchanger and concrete and soil is analyzed,and the heat exchange model is established.The heat transfer model between heat exchanger and concrete and soil is analyzed.(3)The finite element model was established by using MIDAS/CIVIL finite element calculation software.The influence of different working conditions on the heat transfer capacity of energy pile was analyzed.It was found that the difference between the inlet water temperature and the soil temperature was bigger,the greater the temperature difference between the inlet and the outlet The larger the diameter of the pile,the stronger the heat storage capacity of the pile.At the same time,when the pile diameter is 800 mm,the pipe spacing is set to 400 mm,and the pile storage heat is the most reasonable.(4)The comparison of the heat transfer performance of "U" type and "W" type heat exchanger is analyzed.The numerical simulation results show that the inlet and outletwater temperature,heat transfer power,soil temperature change and thermal diffusion of the two heat exchangers under the same conditions Radius with time curve,found that W-type heat transfer performance is better than U-type,but the economy is not as good as U-type heat transfer tube.(5)The thermal influence radius of each energy pile is 2m,which is obviously larger than the thermal influence radius of single pile,which shows that the thermal effect of pile group is not the thermal superposition of single pile. |
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