The Infuence Of Tree-Lned Parking Lot Greening Pattern In Hefei City On Human Thermal Comfort

With the rapid development of China’s economy,the number of motor vehicles has increased rapidly.The construction of parking lot has changed from the traditional open-air parking lot to the tree lined parking lot.With the improvement of urban green space system planning,the function of parking lot in the city has also changed.On the basis of the traditional vehicle distribution center,the ecological and beautifying functions have been derived.The national garden city has brought the promotion rate of tree lined parking lot into the selection standard.Based on the study of the thermal comfort of the parking lot in summer in Hefei,this paper puts forward the optimization suggestions for the construction mode of the parking lot in Hefei,mproves the microclimate environment of the parking lot,and improves the overall thermal environment quality.In this paper,two methods of actual measurement and simulation are used to study the thermal comfort of parking lot.The actual measurement methods are as follows:Taking 9 parking lots in Shushan District of Hefei City,i.e.Aolinge parking lot,AUAU postgraduate building parking lot,Tongluowan square parking lot,Chuntiandasha parking lot,AHAU sixth dormitory parking lot,Huibinlou parking lot,AHAU technical Corridor parking lot,AHAU Lilinxuelou parking lot,Hupotan park parking lot as the research objects,and stopping at the end of July The microclimate factors such as air temperature and humidity,black-bulb temperature,wind speed and solar radiation intensity were measured.In order to reduce the impact of single evaluation index deviation,three thermal comfort evaluation indexes were used,namely,wet black bulb temperature(WBGT),average radiation temperature(Tmrt)and physiological equivalent temperature(PET).The simulation method is:using sketch up and eco-tech software to simulate the shading effect of tree spacing in different parking lots,and get the optimal plant spacing in different directions.The results show that Compared with the control point,WBGT,Tmrt and PET in the parking lot decreased by 26%on average,and the thermal environment improved significantly.The canopy shadow coverage in the parking lot has a significant impact on the thermal environment.The linear regression equation between the canopy shadow coverage and WBGT is:WBGT=-0.061x+28.860(x canopy shadow coverage,the same below);the linear regression equation with the Tmrt is:Tmrt=-0.111x+32.818;the linear regression equation with the physiological equivalent temperature PET is:PET=-0.076x+32.904.According to the measured results,the best planting method for thermal comfort in Hefei in summer is Arbor irrigation type,and the order from the best to the worst is Arbor irrigation type,arbor type and shrub type.In the plant spacing simulation,take the tree with crown of 5m and height of 7m as an example.In the vertical parking space,the best plant spacing is 6m;in the North-South parking space,the plant spacing must be reduced to 4m;in the southeast northwest and northeast southwest parking spaces,the plant spacing can be appropriately expanded to 8m,which can ensure that there is shade shelter in the most intense sunshine period of a day,which is also relatively appropriate.In parallel parking spaces,6m plant spacing is suiTab for parking lots in all directions.When the parking lot trend is southeast northwest and northeast southwest,the plant spacing can be appropriately expanded to 8m.In the inclined parking lot,at the hottest 14:00 time of the day,even under the plant spacing of 4m,the trees in the east-west and northeast southwest directions cannot provide enough canopy shadow coverage;the best plant spacing in the north-south direction is 6m,and the best plant spacing in the southeast northwest direction is 8m.It is concluded that the north-south direction should be selected as much as possible in the greening optimization of the parking lot,and the canopy shadow coverage rate should be increased at the same time.In the plant spacing optimization,according to the simulation results to ensure the continuity of shade in the period of strong sunshine.The research results can not only provide scientific basis for the optimization strategy of parking lot greening mode in Hefei and even surrounding areas under the principle of"people-oriented",improve the scientificity of urban parking lot construction,but also better guide the planning and design of road green space in urban green space system,provide more comforTab and safe urban thermal environment for residents,and realize sustainable development.