Study On Evaluation Method Of Double Skin Roof Of Grain Warehouse Based On Combined Weighting And TOPSIS Method

In the process of Grain Warehouse,due to improper cooling treatment before the grain into the warehouse,when the outside world heats up through the heat transfer of the enclosure structure,the temperature of the warehouse rises,which will intensify the grain from breathing and produce the hidden danger of condensation and mildew.In the enclosure structure of Grain Warehouse,due to the poor insulation performance of the roof,about 80%of the heat in the warehouse from the roof.The roof is the main part of heat transfer,and timely adoption of effective measures to isolate the external heat from the roof can significantly reduce the heat gain of the Grain Warehouse enclosure.In this context,the renovation of roof insulation of existing cottage Grain Warehouse can reduce the cost of cooling in summer and realize the green Grain Warehouse mode with low energy consumption and less fumigation,which is in line with the "double carbon" policy guidance advocated by the state.Commonly used roofing insulation transformation measures in civil buildings include EPS insulation board roof,Double skin roof,additional insulation slope roof,gypsum board ceiling,planting roof,among which overhead ventilation roof is widely used.Double skin roof can not only block the sunlight and reduce the heat directly transferred to the roof by solar radiation,but also use natural ventilation to take away the solar radiation heat in the ventilation interlayer.In this study,the multi-objective decision making method is used as the theoretical basis to select eight evaluation indexes from four aspects: economy,thermal insulation performance,building energy consumption and safety,to form a decision-making index system for the renovation plan of Grain Warehouse double skin roof.Among them,the economic indexes include initial investment and operation cost,the thermal insulation performance indexes include hollow board thickness and material performance,the building energy consumption indexes include hollow floor height and cooling energy consumption,and the safety indexes include hollow board bearing capacity and hollow board service life.In order to make up for the shortage brought by single assignment,the combination of objective assignment method(entropy method)and subjective assignment method(AHP)was firstly used to assign weights to the evaluation indexes,and then the combination weight assignment method was incorporated into TOPSIS evaluation system to construct AHP-entropy-TOPSIS evaluation model to analyze the index system of Grain Warehouse double skin roof renovation scheme for decision making,and the application of The TOPSIS method was used to determine the closeness of each solution to the ideal solution and then the optimal solution was determined.This paper proposes a new multi-objective combination of weighted decision making method to systematically provide a decision basis for the selection of insulation retrofitting solutions for Grain Warehouse.