The Research Of Built Environment Applied Photovoltaic

Energy shortage and environmental pollution are two severe challenges that human beings face in survival for a long time.It is one of the most direct and effective ways to copy with above problems by replacing traditional fossil energy supply increasingly with photovoltaic(PV)power generation based on the solar cell.The built environment is the artificial environment built to meet the demands of human activities.The advantages of PV application include closely combination of energy production and energy consumption,further developing the potential of developed land and saving the land occupied by centralized power stations,and greatly reducing the loss of longdistance transmission lines.Meanwhile,it can also reduce the pressure of peak demand for electricity,and the generated surplus power can be connected to the grid,thus promoting the regional economic level and reducing the use of fossil energy and carbon emissions.Therefore,it is of great significance to study the PV application of the built environment.Based on the concept of PV application of the built environment proposed by the International Energy Agency in 1997 and the PV application technology updated and developed in recent 20 years,this paper improves the concept of the PV application of the built environment from the aspects of application scope and the related economic,social and aesthetic effects,and defines the scope and mode of PV application of the built environment.Therefore,the suggestions on application mode of PV modules of PV application in the built environment and on selection of PV modules are put forward.The influence of economic environment,aesthetic environment and social environment should be fully considered.Moreover,based on the research of International Energy Agency,the suggestions on design form standards for PV application of the built environment are further improved.The design process for PV application of the built environment is proposed at the same time.The scheme evaluation phase is added to reduce the public's negative attitude towards PV application and promote the implementation of PV application projects.This paper also reviews literature on existing methods for evaluating the potential of PV application in built environment.It is found that there are relatively few methods for evaluating the potential of non-building PV application in the complex environment.This paper also proposes evaluation method for PV potential of parking lot based on the combination of orthophoto and GIS and evaluation method for PV potential of the built environment based on the combination of 3D point cloud reconstruction and GIS.Combined with the literature study,this paper classifies and compared different evaluation methods for PV application potential of the existing built environment.The application scope of different methods is summarized.Besides,the proposed two methods for evaluating the potential of PV were used as examples.The PV application potential of parking lot in a university in Tianjin,and of a parking lot in Singapore and building roof is tested respectively to verify the feasibility of above two methods in the actual operation.Nevertheless,the application of PV in large-area built environment is bound to affect the regional thermal environment.For the sake of understanding the impact of diverse PV modules on the local thermal environment,this paper first compares the micro thermal environment temperature fields of different PV modules installed on the roof of the building in accordance with field measurements.It was confirmed that the PV modules with high efficiency and high reflective material on the back had the most obvious influence on reducing the micro thermal environment of concrete roof under the condition of mounting clearance.In addition,experimental comparison test was performed on the influence of green roof,PV application on roof and non-occluded concrete roof on the micro thermal environment temperature field,indicating that the green roof have the most obvious effects on decreasing the influence of concrete roof on regional thermal environment,followed by the PV applications on roofs.Thirdly,comparing with the upside and backside surface temperatures of PV modules made of different materials,it is concluded that the difference in the temperature between the upside and backside of PV modules is mainly associated with backing materials of PV modules.If the backing materials are high reflective materials,the difference in temperature between upside and backside surfaces during the daytime is about 1?,and the temperature in the nighttime is the same.Lastly,the test data of the air heat transfer distance on the back of the PV modules was collected.It was confirmed that the heat transfer distance under the rooftop PV modules in Singapore was about 6.2cm.The philosophy,equipment,program and primary result of the test conducted above can also provide guidance for micro regional thermal environment of other components of the built environment.To sum up,this paper discusses the PV application of the built environment from conceptual definition,design methods and processes,potential evaluation as well as the impact of local regional thermal environment to provide theoretical and technical support for the productive transformation of the built environment in the future.