Photothermal Properties Of Glassing Window Containing Silica Aerogels And Phase Change Materials

Window filled with phase change material(PCMW)can improve its thermal capacity and thermal inertia and other thermal performance,slow down indoor temperature fluctuations,and improve indoor thermal comfort,which has a bright future in building envelopes.However,under severe winter conditions,the phase change material dissipates too much heat to the outdoor environment,which makes it impossible to achieve an effective phase change process and affect its light transmission performance.Adding silica aerogel to the outer interlayer of PCMW to construct a glass window containing silica aerogel and phase change material(SPCMW)to ensure the energy storage / releasing process of the phase change material,which can effectively utilize solar energy and reduce energy consumption of building envelope.However,the photothermal characteristics of SPCMW are significantly affected by silica aerogels.Therefore,in this paper,photothermal properties of SPCMW was investigated.First,the silica aerogel was prepared experimentally,and the photothermal properties of the silica aerogel were measured.Secondly,a SPCMW test bench was set up to compare and analyze light and heat characteristics of hollow glass windows,glass windows containing phase change material,glass windows containing silica aerogels,SPCMW.Thirdly,the effects of the properties of silica aerogels on the heat transfer performance of SPCMW was investigated by numerical simulation.Finally,the performance of SPCMW was evaluated through four aspects: energy consumption level,economy,investment payback period and environmental benefits.The main contents of this paper are as follows:(1)Based on the sol-gel method,several groups of silica aerogel samples under different volumetric concentration ratios,p H values,hydrolysis time,and distilled water volumes were prepared,and their thermal conductivity and UV-visible spectrum were measured.The results show that different preparation conditions have a significant effect on the photothermal properties of silica aerogel.(2)Set up a SPCMW light and heat transmission experiment bench.Contrast research on light and heat transmission of four kinds of glass windows: hollow glass window,glass window containing phase change material,glass window containing silica aerogels,SPCMW.The results show that the light transmittance and inner surface temperature of SPCMW are lower than that of hollow glass windows,glass window containing phase change material and glass window containing silica aerogels.(3)A two-dimensional non-steady-state heat transfer model for a SPCMW.Develop UDF code for outdoor environmental conditions in severe cold regions,and study the influence of physical properties of silica aerogels on the dynamic heat transfer performance of SPCMW.The feasibility of silica aerogels in improving the heat transfer performance of glass windows containing phase change materials was investigated from the aspects of liquid phase ratio and inner surface temperature of glass windows.The results show that the silica aerogel can ensure the effective phase change process of the phase change material under the winter climate conditions in severe cold regions.(4)Establish a rural residential model in severe cold areas,and four kinds of glass windows:hollow glass window,phase change material glass window,aerogel glass window,SPCMW were researched and analyzed in four aspects: energy consumption level,economy,investment recovery period and environmental benefit.The results show that the use of SPCMW reduces building energy consumption and protects the environment.The research results in this paper can provide scientific references for the future engineering application and development of SPCMW,and provide certain theoretical and data support for engineering applications in severe cold regions.