Experimental Study On Penetration And Cooling Performance Of New Urban Outdoor Green-way Cold Plate Module

The urban hard underlay surface area accounts for about 70%～80%of the urban surface area,and the resulting urban heat island effect and waterlogging disaster seriously affect the normal production and living activities and restrict the urban prosperity and development.Permeable pavement is an important part of sponge city construction,which can not only improve the outdoor hot and humid environment and purify the air,but also eliminate noise,alleviate the heat island effect,rainwater infiltration and storage,and reduce pollution.The permeable road not only reduces the flood peak but also reduces the outdoor temperature locally.Based on this,further understanding and study of permeable pavement has a positive and far-reaching significance to improve the urban heat island effect and flood disaster.In this paper,a new urban outdoor greenway cold plate module experimental test system is designed on the basis of permeable pavement.The test system mainly consists of greenway cold plate module,simulated rainfall system and temperature test system Permeability experiments to simulate light rain,moderate rain,heavy rain,heavy rain and heavy rain conditions such as testing,cooling performance experiment under the condition of the outdoor weather conditions similar to test the influence of different heat pipes pipe flow temperature changes to a module,respectively for the two new urban outdoor green way of cooling-plate module penetration performance and cooling performance evaluation parameters,for engineering application module provides the basic experimental basisThe experimental test module is composed of pervious concrete module and soil planting module.The pervious concrete module is referred to as module A,and the new urban outdoor greenway cold plate module is referred to as module B,which takes the pervious concrete layer as the surface layer.The experimental results show that:in terms of rainwater penetration,the total permeability of module A is 61.5%～78.8%under different rainfall intensity.The total permeability of module B ranges from 0%to 76%,respectively The permeability of module A is better than that of module B,and the rainwater retention effect of module B is better than that of module A.Under the same condition,the time of module flow production decreases with the increase of rainfall intensity.Cooling performance:the average temperature drop of the surface layer of module A in different working conditions is 0.74℃～2.64℃,and that of module B in different working conditions is 0.39℃～1.09℃.Under different flow conditions in the cold plate tube,the surface temperature drop of both modules increases linearly with the flow,and the temperature drop response of module A is more obvious.Temperature delay:during the experiment,the peak of solar radiation intensity appeared between 12:50～14:00.The average delay time of peak temperature in surface layer,gravel layer and grille layer of module A was 2.5 times,3.8 times and 1.1 times that of the blank control group,while that of module B was 0.9 times,3.7 times and 1.02 times.Accumulative heat exchange:the accumulative heat exchange per unit area of module A under different working conditions is 1190.7kJ/m2～2087.1kJ/m2 respectively.The accumulative heat exchange per unit area of module B under different working conditions is:684kJ/m2～1262.7kJ/m2,respectively.Based on the hydrodynamic principle of porous media,the mass conservation of air and water in the structure of the module is(?);The permeability rate of the module is related to the saturation hydraulic conductivity of the module.The heat equilibrium equation of module A is 1316qrad=(7.98-5.32v)(Ts,A-Tair)△τ+7.46[(Ts,A+273/100)4-(Tair+273/100)4]Δτ+150(Ts,A-Ts0,A)+252(Tg,A-Tg0,A)+2793(Twater,A-TwO,A);The heat equilibrium equation of module B is 182qrad=1214ΔT+(7.98-5.32v)(Ts,B-Tair)Δτ+1.43[(Ts,B+273/100)4-(Tair+273/100)4]Δτ+339(Ts,B-TsO,B)+252(Tg,B-TgO,B)+2793(Twater,B-Tw0,B).