Study On Performance Optimization Of Office Building Envelope In Sichuan Tibetan Region Based On Solar Energy Utilization

Sichuan Tibetan region is located in the Hengduan Mountains of the Qinghai-Tibet Plateau,with a severe winter climate and a lack of heating resources;however,the region is rich in solar energy resources,and if certain technical measures are taken to make full use of solar energy resources in the process of building design and use,the energy consumption of the building is bound to be greatly reduced.The paper takes an office building in the Sichuan Tibetan region as the object,combines the climate characteristics of the Sichuan Tibetan region,the functional characteristics of the office building and the characteristics of use,and carries out a suitable office building envelope wall form and its structural parameters optimization research in the Sichuan Tibetan region,the research work and research results have important engineering practical value and engineering guidance significance.First of all,through literature review,combined with field research and actual measurement,the paper summarizes the climate characteristics and energy status of the Tibetan area in west Sichuan,investigates the existing office building structure form and winter heating status of the Tibetan area in west Sichuan.By compiling and analyzing the data,it can be found that:the winter temperature in Sichuan Tibetan region is low and the temperature difference between day and night is large(taking Kangding as an example,the average daily temperature in winter is 2.7℃,the maximum daily temperature is 20℃and the minimum daily temperature can reach-12℃);the daytime horizontal solar radiation value can reach 800W/m~2;the average unit area heat supply of existing office buildings in winter is 65.80W/m~2.With the advantage of solar energy resources and high energy consumption of existing office buildings,it is suitable to promote the application of solar energy utilization technology in the energy-saving renovation of office buildings.Secondly,the paper compares and analyzes the heat transfer performance of several commonly used facades in low altitude areas in office buildings in the Sichuan Tibetan region through numerical simulation methods,and discusses the advantages and shortcomings of the application of different facades.Under non-heating conditions,compared with rooms with existing facades,insulated facades,glass curtain walls and solar collector walls,rooms with solar collector walls(internal vents)can be improved by at least 2°C(maximum room temperature up to 21°C during daytime)and room temperature at least 1-2°C at night(minimum room temperature 12°C at night).The solar collector wall(internal vent)has good heat collection and insulation performance and is suitable for application in office buildings in the Sichuan Tibetan region.Then,based on effectively reducing the effect of cold radiation at night in winter,the thesis proposes the structural form of the new solar collector wall based on the existing solar collector wall(internal vent);using the total heat transfer from the new solar collector wall to the room as the evaluation index,the numerical simulation is used to analyze the inner window area,inner window material,air interlayer width,vent area,wall thickness and material,and inner shade material of The calculation results show that:the increase of the inner window area can increase the solar radiation heat entering the room,but the internal ventilation heat transfer will decrease with the increase of the inner window area,and the optimal window-to-wall ratio is 0.1;the inner window material is recommended to use high transmittance glass;the width of the air interlayer has a significant influence on the air flow pattern inside the interlayer,and the optimal width is50mm;the increase of the vent area will increase the internal ventilation heat transfer and decrease the wall heat transfer at the same time.The recommended value is 1.5%of the wall area;the smaller the thickness of the wall,the greater the total heat transfer of the wall,but the heat storage and thermal insulation performance of the wall also decreases;the recommended thickness of the wall is 180mm or 240mm;when the wall thickness is the same,the greater the thermal conductivity of the wall material,the greater the total heat transfer of the heat collecting wall;at night,setting curtains inside the mezzanine can effectively reduce the heat transfer of the heat collecting wall to the outside at night.At night,setting curtains inside the mezzanine can effectively reduce the heat transfer from the heat collecting wall to the outside at night,and the lower the long-wave emissivity of the material,the better the heat collecting wall insulation effect at night.Finally,the paper establishes a model of office building based on a new solar collector wall with an office building in Kangding as a prototype,and simulates and analyzes the winter heating energy consumption of the building.Through the comparative analysis of the simulation results,it can be found that:when the main facade of the building faces south,the energy saving rate of the office building with the new solar collector wall can reach 51.25%compared with the existing office building in the form of envelope structure,and the energy saving rate reaches 34.18%and 37.67%when the building faces east and west respectively,indicating that the new solar collector wall has good energy saving effect and can be used in the Sichuan Tibetan region.The new solar collector wall has good energy-saving effect and can be promoted and applied in the energy-saving renovation of existing office buildings in Sichuan Tibetan region.