| The Sichuan-Tibet Railway starts from Chengdu,Sichuan Province in the east and ends in Lhasa,Tibet Autonomous Region in the west.The outdoor environment along the line is complex,with high average altitude and most of the areas belong to cold and severe regions,and the severe outdoor weather conditions seriously affect the indoor thermal environment and building energy consumption of housing buildings along the line.Prefabricated buildings have the advantages of being free from environmental constraints,energy saving and environmental protection,and short construction periods.For the multi-storey housing structures along the Sichuan-Tibet Railway,the use of prefabricated buildings can improve productivity,promote the industrialization and standardization of railroad life housing buildings,and achieve " Green,environmental protection,energy saving" construction concept.At present,domestic and foreign scholars have little research on the indoor thermal environment and building energy consumption in high-cold and high-altitude areas,and the research on railroad life housing buildings is mostly at the structural level.Therefore,this paper combines the thermal characteristics of prefabricated buildings and outdoor environment in high-cold and highaltitude areas,and conducts thermal analysis of prefabricated railroad life housing buildings along the Sichuan-Tibet railway line.Firstly,by considering the possible thermal bridge effect in the prefabricated buildings and taking the average heat transfer coefficient of the external wall as the key parameter,the thermal design method considering the thermal bridging effect is proposed for DeST software,and the correctness and applicability of this method is verified by comparing the simulation results with the measured experimental data of references.Secondly,aiming at the high-cold and high-altitude areas of the western Sichuan Plateau and the Tibet Plateau along the Sichuan-Tibet Railway,taking the Ganzi area as an example,the indoor thermal environment and building energy consumption are calculated by the proposed thermal calculation method considering the thermal bridge effect,and important data such as average indoor temperature,indoor discomfort and annual load are obtained.While the model is optimized with the parameters of building orientation,window-wall ratio,average heat transfer coefficient of external walls and heat transfer coefficient of external windows,and a standardized prefabricated railroad life housing building template is obtained for the Ganzi area.Finally,taking Ganzi area as the base point,by extending to the whole line of SichuanTibet Railway,studying the high cold and high altitude areas along the line through Ganzi to Litang,Batang,Qamdo,Nyingchi,and finally to the terminal station Lhasa,studying the changes in the layout and thermal structure of the buildings along the line at each site,and getting the best standardized prefabricated railroad life housing building templates at each site to be applied to the actual construction projects.The specific content of this paper is detailed as follows:(1)Research the domestic and foreign research status of indoor thermal environment,building energy consumption and prefabricated buildings.By analyzing and summarizing the current research status,the vacancies in the current research are found,that is,the research on the indoor thermal environment and building energy consumption of prefabricated railroad life buildings in high-cold and high-altitude areas,and give the research purpose,research content and research technology line of this paper(Chapter 1).(2)The related theories and influencing factors of indoor thermal environment and building energy consumption are expounded,and the building thermal process theory and the simulation method of building energy consumption are introduced.By studying the characteristics of prefabricated buildings,it analyzes the more obvious thermal bridge effect of prefabricated buildings compared with traditional cast-in-place buildings,.By summarizing its unique indoor thermal environment characteristics and its consideration method,a thermal design method that considers the thermal bridge effect of the prefabricated building is proposed(Chapter 2).(3)The method of considering the effect of thermal bridges on the indoor thermal environment of prefabricated buildings by DeST software was used to simulate the actual measured data of indoor temperature of existing prefabricated buildings,and the correctness and applicability of this method were verified by comparing the results of the actual measured data,the simulated data considering the thermal bridge effect and the simulated data without considering the thermal bridge effect(Chapter 3).(4)By applying the thermal design method considering the thermal bridge effect of the assembled building,the thermal analysis of a proposed prefabricated railroad life house building in Ganzi area was carried out to obtain the calculation results of indoor temperature,indoor discomfort and building load of the initial model.The building orientation,south-facing window-wall ratio,average heat transfer coefficient of exterior walls and heat transfer coefficient of exterior windows are used as parameters to investigate the influence of each parameter on the building indoor thermal environment and building energy consumption.Through the design method of orthogonal test,the degree of influence of nine different models on the building indoor thermal environment when each parameter is coupled is investigated,and the best model for standardized prefabricated railroad life housing buildings in Ganzi area is obtained.The conclusions are as follows: in the Ganzi area,when the influence of the four parameters on the indoor thermal environment of the building is comprehensively considered,the model 6 is the best.At this time,the building orientation is 30° south-west,the south-facing window-to-wall ratio is 0.45,the heat transfer coefficient of the exterior wall is 0.15 W/(m~2·K),and the heat transfer coefficient of the exterior window is 1.5 W/(m~2·K).The heat transfer coefficient is 0.15 W/(m~2·K),and the heat transfer coefficient of the exterior window is 1.5W/(m~2·K).(Chapter 4).(5)Aiming at the high-cold and high-altitude areas along the Sichuan-Tibet Railway along the Western Sichuan Plateau and the Tibet Plateau,thermal analysis was carried out for each station along the line: Ganzi-Litang-Batang-Qamdo-Nyingchi-Lhasa.The optimal values of building orientation,window-wall ratio and heat transfer coefficient of the envelope under the condition of meeting the limits of indoor thermal comfort and building energy consumption and their variation laws are investigated to provide a reference basis for practical projects(Chapter 5). |
