Study On Optimization Of Thermal Performance Of Prefabricated Sandwich Wall Panels In Northwest Cold Regions

With the country’s promotion of prefabricated buildings,prefabricated sandwich external wall panels that can be manufactured in factories and realize the integration of insulation and structure have been widely used.However,as the country implements the 75%energy-saving goal of residential buildings,In cold areas such as Ningxia and other severe cold areas,the thermal performance of prefabricated sandwich wall panels needs to be further improved to meet new energy-saving requirements.Therefore,this article uses the prefabrication used in a 5-story prefabricated steel structure dormitory building of Ningxia Yinchuan Changjiang Precision The sandwich external wall panel is the research object,and its thermal performance is optimized based on the structure.The main research work is as follows:(1)Through field investigation and measurement,the material and size of the prefabricated sandwich external wall panels used in the Yangtze River Jinggong dormitory building were clarified,and the detailed structural drawings of the wall panels were obtained,and then the heat transfer coefficient of the wall panels was calculated through theoretical calculations K=0.520W/(m2·K),at this time,the heat transfer coefficient of the outer wall of the dormitory building when the energy saving is 75%is not met,that is,K≤0.45W/(m2·K).(2)Based on the analysis of the original structure and thermal performance of the prefabricated sandwich wallboard,two new structural optimization schemes that can improve its thermal performance are designed on the basis of the original structure scheme of the wallboard,namely Foamed concrete is filled in the blades and a closed air compartment is added to the outer blades.(3)Using the finite element software ANSYS Workbench to perform numerical simulation and analysis of the thermal performance of the prefabricated sandwich external wall panel before and after optimization,it is concluded that the inner blade of the wall panel is filled with a thickness of 40mm,and the thermal conductivity is 0.077W/(m·K)～0.163W/(m·K)or 30mm thick foamed concrete with a thermal conductivity of 0.077W/(m·K)～0.110W/(m·K)can make the heat transfer coefficient of prefabricated sandwich external wall panels K≤0.45W/(m2·K),in addition,the wallboard will not have condensation on the inner surface after inspection.(4)Using the Green Buildingsville energy-saving series software to simulate the energy-saving effect of prefabricated sandwich external wall panels,it is concluded that the dormitory building with optimized heat transfer coefficient K≤0.45W/(m2·K)wall panels and the original use Compared with the dormitory building constructed with wall panels,its heat consumption index and heating coal consumption index are both reduced by 3.3%～5.4%compared with the original index,while the energy saving rate of the dormitory building envelope structure has increased by 15.5%～26.6%,indicating optimization The rear wall panel further saves energy.