Study On The Design Strategy Of Subtropical Pergolas Based On Human Thermal Comfort

As a common garden structure in hot and humid area,the pergola has the advantages of low cost and fast grow.The pergola is a framework that supports climbing plants,and it is able to shade the pedestrians.Sometimes the pergola is independently,and other landscape elements combined with the pergola can also form the complicated landscape space.As an important means of regulating outdoor microclimate,the plant plays an increasingly important role in architectural landscape planning and design.In summer,the microclimate factors of the pergola are closely related to the thermal comfort of human body,such as air temperature,humidity,solar radiation,wind speed,wind direction and so on.In this paper,the design strategy of pergola based on human thermal comfort is quantitatively studied by the method of combination of measurement and simulation.The research results can be used in various common grounds such as parks,squares,roof gardens,etc.This study has a positive role in promoting the construction of a good landscape microclimate and green community,which is conducive to the establishment of low-carbon cities and sustainable development of cities.Based on the above purpose,in the second chapter,the basic types of pergola were sorted out,the forms of pergolas can be divided into "?" type," L " type,corridor type,square grid type," s " type,fan type,circle type,ring type and so on,and the "?" type is selected as the mean type in the following study.In the third chapter,the pergola of Yuexiu Park in Guangzhou is selected as the measuring site,and the horizontal and vertical measuring points are set.The physiological equivalent temperature(PET)is selected as the evaluation index of thermal comfort.Through the analysis,it is found that in summer and transition season of subtropical area,the pergola is able to cool down and increase humidity,and the thermal environment of different positions under the pergola is slightly different: in the horizontal direction,the PET in the center of the pergola is the lowest;in the vertical direction,the closer to the top of the pergola,the lower the PET values.The difference of thermal environment in different positions of pergola is mainly affected by wind direction,Sky View Factor and Leaf Area Index.In the fourth chapter,ENVI-met software is used to simulate the thermal environment of the measuring site,and the applicability and accuracy of the software for the study of the thermal environment of the small-scale garden space such as the pergola are demonstrated.The fifth chapter is based on the above simulation and verification,and simulates the thermal environment of the pergola in different directions,different plant coverage methods and different scales.It is found that when the plant coverage is added to the north of the EastWest pergola,to the east of the corridor in the north-south direction,to the southwest of the corridor in the southeast-northwest direction,and to the southeast of the corridor in the southwest-northeast direction,the effect of thermal comfort form the pergola is better.In the subtropical area with the frequent southeast wind in summer,the long side of the pergola should be set in the upwind direction.When the area of the pergola is fixed,the ratio of width to length is 0.6,which can bring better thermal comfort to the space under the pergola.Finally,the design strategy of subtropical pergolas based on human thermal comfort is put forward in order to provide reference for the design of subtropical pergolas.