The Study Of Numeric Simulation Of Temperature Field Of U-vertical Buried Pipe Of GSHP In Lanzhou Area

In China, building energy consumption has accounted for40%of all energy consumption,including air conditioning and hot water system can accounts for30%~50%of total energyconsumption of buildings, energy conservation and environmental protection are the two mostconcerned topic in the world. So, we need to replace with other heating way of old centralheating mode, and the heat pump is a kind of to reduce air pollution and CO2emissions ofenergy-saving new technology.This paper studied the soil source heat pump technology, due to the dense population inLanzhou, and industrial zone is located in the upstream, residential and business district islocated in the downstream, and has the characteristic of the terrain, makes the whole citypollution is serious, environment problems to be solved. So in Lanzhou region to carry out thestudy of soil source heat pump is very meaningful.This paper collects and analyses theclimate characteristics, soil characteristics data in Lanzhou. To calculate the soil initialtemperature in Lanzhou, and determined the soil initial temperature, this is important for laterin the simulation.The rationality of soil source heat pump heat exchanger design directly affects the heattransfer performance of the whole system, and the heat transfer performance has relationshipwith underground soil temperature field distribution.In order to research on heat transfercharacteristics of the heat exchanger in detail, in this paper, the single U heat transferperformance of heat exchanger and the surrounding soil temperature field distribution of thenumerical simulation study, mainly done the following work:(1)In this paper, first of all, in the aspect of heat transfer theory, through the analysiscomparison of analytical solution and numerical solution of the two heat exchanger heattransfer model，to set up the simplified model of a two-dimensional unsteady temperaturefield around single U tube.(2) Using ANSYS finite element analysis software, simulation of the soil around theu-shaped tube unsteady temperature field, Simulation is obtained in the different periods ofsoil temperature field distribution and the change rule of temperature field model along theradial.(3) Under the assumptions of soil is the isotropic and homogeneous porous media, to setup the three-dimensional model of the U tube heat exchanger and the surrounding soil.(4) Simulated under the condition of different inlet velocity, fluid pressure in U tube andu-shaped tube cross-section velocity distribution, to verify the model of this paper is accord tothe actual situation.(5) Based on different inlet velocity, coefficient of thermal conductivity backfill materialsand different circulation medium inlet temperature under the condition of simulation analysis,respectively obtained the temperature field distribution of the inside, outside the drilling and the u-shaped tube. Study concluded that with the increase of backfill material coefficient ofthermal conductivity, inlet velocity increase and higher inlet temperature of circulatingmedium, heat exchanger heat transfer will be increased. And the coefficient of thermalconductivity of backfill materials effect is particularly obvious.Through the above simulation analysis, can provide some reference for practicalengineering design.