Study On Dynamic Insulation Performance Of Aerogel Roof Based On RC Heat Network Model

Building envelope is mainly composed of roof,exterior wall,doors and windows.In the way of building loss to the outside world,the energy loss caused by roof heat transfer accounts for 25%-30%of the total energy loss of the building.Roof thermal insulation technology is an important measure to reduce building energy consumption.At present,the widely used traditional roofing thermal insulation materials still have the problems of fast aging,easy combustion and high water absorption.Therefore,it is urgent to develop and apply new thermal insulation materials to fundamentally solve the quality problems and safety risks of traditional thermal insulation materials and improve their thermal insulation performance.Therefore,this paper took Guangzhou,a typical city in hot summer and warm winter region,as an example,and carried out a full-scale roof insulation performance experiment using a new type of ultra-high thermal performance aerogel insulation plate（AIP）from the perspective of practical application,and systematically carried out a comparative analysis and study of its dynamic insulation performance by using a simplified and efficient RC heat network model.The main research work of this paper includes:（1）The performance of the selected aerogel insulation plate was tested and characterized.Including density,thermal conductivity,microstructure,properties of hydrophobic,the infrared spectral transmittance and mechanical property test,the results show that the density of aerogel insulation board in 185.6 kg·m^-3,low heat conduction coefficient 0.023 W·m^-1·K^-1 has good hydrophobic properties（hydrophobic Angle is 132.13°）,the compressive strength is 1.62 MPa,good comprehensive for its application in the building roof to achieve energy conservation and emissions reduction laid a foundation.（2）An aerogel roof experiment platform was established based on the actual engineering background,and the RC heat network model was combined with the roof.To promote the aerogel insulation board in the roofing construction,the application of the aerogel thermal insulation board used in roofing and building the experiment platform,get relevant outdoor meteorological parameters and temperature data,the results and according to the principle of thermoelectric roofing RC network model of the simulation results were analyzed,the results showed that the roof of the internal and external surface temperature calculation value and the actual test value almost the same change trend,good agreement,outside surface temperature the average temperature deviation is 5.9%;The average deviation of internal surface temperature is 2.0%,which verifies the reliability of the roof RC heat network model.（3）Determine the optimal construction mode and the optimal insulation thickness for engineering application of aerogel insulation board in roof.Based on RC network model,by using conventional building roof structure,studied the aerogel insulation board in the practical application of building roof insulation performance,the results show that the AIP has more advantage in roof insulation performance,the attenuation ratio increased by 19.4%-60.5%compared with the traditional heat insulation roofing,delay time is 5.25 h,longest daily energy consumption can be reduced by 14.3%-32.8%;The dynamic thermal insulation performance of the inverted roof structure is better than that of the upright roof.When disturbed by the fluctuation of the external thermal environment,the inverted roof can adjust the indoor temperature more quickly and effectively,and maintain the comfort and stability of indoor thermal environment.The increase of the thickness of AIP has a favorable effect on the temperature and heat flux of the inner surface of the roof.Through the analysis and further study of the relationship between attenuation factor,delay time and AIP thickness,it is determined that the daily energy consumption can be used to guide the corresponding function relationship between AIP thickness in real engineering,which provides data support for the practical engineering application of aerogel insulation roof.The research results can provide a scientific basis for optimizing the insulation performance of roofing,promote the application of aerogel insulation board in building roofing,further promote building energy saving,and help achieve the goal of"carbon neutral".