Comparative Experimental Study On Optical And Thermal Properties Of Nano-silica Aerogel Glass System

Nano-silica aerogel is a new type of light-transmitting and thermal-insulating material.Architectural windows with aerogel glass have energy-saving potential.As the aerogel optical parameters-extinction coefficient is difficult to determine,it is difficult to theoretically analyze the lighting effects and energy saving potential of the aerogel glass in the actual weather conditions.Therefore,it is necessary to evaluate the daylighting effect and energy saving potential of aerogel glass by experimental study.In this study,a comparative experimental platform for aerogel and hollow glass was set up,and the parameters of radiation,illumination and temperature were measured under the same climate condition.In this paper,the thermal and optical properties of aerogel glass and hollow glass were compared under four kinds of weather conditions,such as sunny day,cloudy day,cloudy day and rainy day on summer in Changsha.By measuring the total solar radiation and scattered radiation inside and outside of the aerogel glass and hollow glass,the comparative study shows that compared with the hollow glass,the solar radiation entering through aerogel glass is reduced by 45%,and it is basically a diffuse radiation.That is to say,compared with the hollow glass,the transmittance of the glass to the solar radiation is greatly reduce,which means the indoor solar radiation heat gain is greatly reduced.In addition,due to the scattering of solar radiation by the aerogel,when the solar radiation enters the room through the aerogel glass,almost all the scattered radiation.By measuring the indoor light intensity and comparing the visible light transmittance on sunny and cloudy day,analysis shows that the aerogel glass lighting effect on sunny day is better than that on cloudy day.The aerogel glass' visible light transmittance reduction rate on sunny day is 23%?45%,compared with hollow glass,which in cloudy day,reduction trate is 37%?53%.In addition,the studies also compared the indoor illumination of aerogel glass and hollow glass on cloudy and rainy day,whici shows that the cleaner the weather is,the better lighting effect of aerogel glass will be.The temperature analysis shows that,compared with the hollow glass,the surface temperature of all layers in aerogel glass is higher because of the absorption of aerogel to radiation,and the greater the outdoor solar radiation is,the higher the temperature will be.Energy consumption analysis shows that total heat gain through the aerogel glass is 37%less than that through the hollow glass on sunny day,and 36.7%on cloudy day.Through the experimental data,this paper discusses the method of the present thermal calculation of glass,and puts forward the linear fitting formula of the heat gain of aerogel glass.In this paper,a comparative experimental platform for aerogel and hollow glass was set up,through the contrast analysis of aerogel glass and hollow glass,The results show that the aerogel glass has a great potential for energy saving in Changsha area,and which is accompanied by good lighting performance.