Study On The Influence Of Horizontal Buried Pipe Laying In Subway Air Conditioning

Because of its safety,comfort,punctuality,rapidness and efficiency,large volume of transporting passengers and less environmental pollution,metro has played an essential role in alleviating traffic pressure.In addition to its convenience to urban residents,metro has also aroused many problems.Under the background of massive construction of the metro in China,in particular,its energy consumption issue has been paid more and more attention,of which the energy consumption of air conditioners accounts for 30%of the total's.Especially for traditional air conditioners,on the one hand,the cooling towers occupies large space,on the other hand,the generated noise and exhausted air exert a certain impact on the surrounding environment.For this problem,this paper is going to adopt the horizontal buried pipes with the buried depth being 10m to 20m to provide the cooling capacity for a metro station,and in this way,the heat in the soil can be easily discharged into the atmosphere.Firstly,this paper adopts TRNSYS to stimulate and calculate the hourly load of Zhengzhou metro station and get the hourly cooling load of the metro station in summer,then analyses the composition of the station's load,and makes a selection of air conditioning equipment of environmental control system.Secondly,a GSHP horizontal buried pipe simulation platform was set up in TRNSYS and the outlet temperatures of horizontal U-shaped buried pipe were stimulated and calculated with different buried depths and different spacing.Finally,ANSYS/FLUENT software was used to simulate and calculate the soil temperature distribution around the horizontal spiral buried pipe.An indicator(the heat transfer per meter length of linear meter)was used for evaluating the heat transfer performance of horizontal spiral buried pipe under different setting conditions of spacing,pitch of screw and so on.In the last,the optimum buried location for metro station was obtained.Through analysis of data,it can be obtained:(1)using U-shaped buried pipe under metro air-conditioning environmental control system,in the Scheme E,under the condition of the depth being 10m and 20m and spacing being 1.0m,the pipe outlet temperature is 32.3?,and the floor area is 5400m~2.In the Scheme F,under the condition of the depth being 10m and 20m and spacing being 1.0m,the pipe outlet's peak temperature is 32.1?,and the floor area is 7650m~2.(2)In the Scheme S,under the condition of the pitch of screw being 1.0m,pitch being 1.5m,and the heat transfer per meter length of linear meter being 31.1w/m,it calls for a total length of 13665m of pipes and the spiral pipe occupy approximately 3654m~2.In the Scheme T,under the condition of pitch of screw being 1.0m,pitch being 2.0m,and the heat transfer per meter length of linear meter being 32.3w/m,it calls for a total length of 13157m of pipes and the spiral pipe occupy approximately 4327m~2.After the analysis of data,it can be found that the best laying method of horizontal U-shaped tube is that the double laying with the depth of 10m and 20m and the spacing of 1.0m.The optimum buried location for horizontal spiral tubes is under the condition of the pith of screw being 1.0m and pitch being 1.5m.In this way,the comprehensive energy-saving effect of horizontal spiral buried tube is significant and it can be promoted and applied in the areas where the summer is hot and winter is cold.