Analysis Of The Thermal Environment Of Xi'an City Square In The Effect Of Solar Radiation

As a place for recreational and social activities of urban residents,the quality of city square has an impact on the use of people,because the construction of the city square lacks consideration of the thermal comfortable feelings,and some of the squares are large and improper,and the layout of the space is not reasonable.In order to meet people's requirements for using the city square at different times in thermal comfort environment and improve the use rate of the square,this research studies the thermal environment characteristics of the city square based on related principles and measured data,and then proposes that it can meet people's needs for thermal comfort in different periods of use.Spatial adjustment strategies provide ideas and basis for climate adaptive design of city square.Because the solar radiation is the main source of the field energy,the research on the thermal environment of the square is mainly from the analysis of the process of the interception,absorption and transformation of the solar radiation by the elements of the square space,and considering the daily and seasonal variations of the solar radiation,and analyzing the different periods and different seasons in the square.The study of thermal environment mainly includes the following four parts:(1)By combing the basic principles of the thermal environment analysis of the city square under the action of solar radiation,clearing the analysis of thermal environment of the square on the thermal comfort of the human body is cleared.(2)Through the investigation and characteristic statistics of the city square in Xi'an,the type of construction is classified according to the building enclosure,and the characteristics of the shadow proportion in the square under different enclosure and D/H ratio are analyzed,and the characteristics of different basement in the square are also characterized.The analysis of the plant coverage determines the difference in the solar radiation reaching the ground and affects the overall thermal environment and the local spatial microclimate characteristics of the square.By analyzing the components of the square,the way of space restriction,and determining the influence factors of the space form,the different spatial composition patterns are extracted.(3)Through the related principles and measured data,the thermal environment characteristics of different spatial patterns of ground material and plant factors are mainly analyzed.On the one hand,from the angle of influence of spatial morphological factors,such as material type,area ratio,plant cover area,under crown,and on the other hand,from surface material and plant The influence on the thermal environment of the square and the characteristics of the thermal environment in different periods are analyzed in the light of the sunshine period and the material related properties of the space.(4)At last,from two aspects of solar radiation and air temperature,the thermal comfort status of different spatial composition patterns in winter and summer square,and the time characteristic of relative comfort in the whole day are analyzed,and the adjustment function of different spatial composition models to the thermal environment of square is further analyzed with the ENVI-met software simulation.The main conclusions of this study are as follows:(1)The effect of different open-air ground material space configuration modes on the thermal environment of the city square,summer heat storage and absorption of less floor materials has a good improvement effect on the space thermal environment;the square should be avoided in an area of hard pavement Space,for the same area square rigid pavement,scattered pavement is more conducive to improving the space thermal environment than the overall large area pavement.(2)The influence of spatial pattern of different plant cover on the thermal environment of the urban square.Results and simulations are available.The larger the area covered by vegetation,the canopy density is about 30-40%,and there is better regulation of the thermal environment under the crown.The greater the canopy area of the plant,the lower the temperature of the canopy center during the day,and the relatively stable range;(3)The effect of different spatial combination modes on the thermal environment and comfort period of the city square,controlling the area ratio of hard and soft floor materials,the greater the proportion of grassland area,the better the cooling effect on the overall space;the plant coverage space and open air In the combined mode of paving,the range of arrangement of planting plants in the north-south direction is greater than that in the east-west arrangement of the canopy,and it can provide people with relatively long comfort zones on the east and west sides.