Influence Of Structure On Heat Transfer Characteristics Of Insulation Window Filled With Phase Change Materials

The glass window filled with phase change materials(PCMs)can improve its optical-thermal transfer characteristics to realize the optical-thermal collaborative utilization.The window filled with PCM has the bright future in the application of energy saving building due to the advantages of thermal inertia and heat insulation.It has become the hot spots in the research of glass window.The phase change process of paraffin is easily affected by its thermophysical properties,environment and other factors,which leads to the inharmonious between indoor optical-thermal environment and paraffin phase change.Therefore,the author’s team built the insulation window filled with silica aerogels and PCMs to control solar energy absorption and to enhance the insulation performance of glass window.It solves that the problem of inharmonious between paraffin phase change process and indoor optical-thermal environment.However,the previous experiments show that the window frame has a great influence on the heat transfer characteristics of the insulation window filled with PCMs,which directly affects the thermal performance of the window.In order to improve the thermal performance of the insulation window filled with PCMs,this paper proposes the structure relies on inserting polyurethane into the frame of insulation window filled with PCMs.The influence of the section of frame and glass with paraffin and silica aerogels on the thermal performance of the whole window was studied.In this paper,the research on the photo-thermal utilization of insulation window filled with silica aerogels and PCMs was investigated.First,a two-dimensional thermal transfer model of insulation window filled with silica aerogels and PCMs was established,and the impact of insulation frame and glass with paraffin and silica aerogels on the thermal transfer was investigated.Next,the influence of different frame-glass ratio on the heat transfer characteristics of the insulation window filled with silica aerogels and PCMs was analyzed.Considering the frame structure,glass structure and the linear heat transfer coefficient at the joint between frame and glass,the method of calculating the heat transfer coefficient of the whole window was modified.Finally,the performance of insulation window filled with silica aerogels and PCMs was evaluated in terms of energy consumption,economy,payback period and environmental benefits.The main contents of this paper are as follows:1.In order to analyze the heat transfer characteristics of the window frame structure,a two-dimensional steady-state heat transfer model of the window frame structure was established.The effects of different filling methods,filling positions and filling amounts on the heat transfer characteristics of the frame were studied.It was found that the heat transfer coefficient of the window frame filled polyurethane can be reduced by 46.8%.2.A two-dimensional steady-state heat transfer model was established to analyze the heat transfer characteristics of glass structure filled with silica aerogels and PCMs.The influence of thickness of silica aerogels and paraffin on the heat transfer performance of insulation window filled with silica aerogels and PCMs was compared.Then the influence of nanoparticles on the heat transfer characteristics of the insulation window was analyzed.The results show that the heat transfer coefficient of insulation window filled with silica aerogels and PCMs is 1.19 W/(m~2·K),which is 42.79%lower than that of glass window.The temperature rise rate of paraffin layer in the insulation window filled with nanoparticles is faster than insulation window filled with silica aerogels and PCMs,but the heat insulation performance is lower.3.A three-dimensional steady-state heat transfer model was established to analyze the heat transfer characteristics of insulation window filled with silica aerogels and PCMs.The influence of different frame-glass ratio on the heat transfer characteristics of insulation window filled with silica aerogels and PCMs was compared and analyzed.The method of calculating the heat transfer coefficient of the insulation window filled with silica aerogels and PCMs was modified.The results show that the frame-glass ratio has a great impact on the heat transfer characteristics of the insulation window.When the frame-glass ratio increases from 20%to 30%,the heat transfer coefficient of the window decreases by 4.2%.4.The energy consumption of rural residential buildings with insulation window filled with silica aerogels and PCMs with different window-wall ratios and different building orientations.The performance of insulation window filled with silica aerogels and PCMs was evaluated in terms of economy,payback period and environmental benefits.The results show that the installation of insulation window filled with silica aerogels and PCMs in rural residential buildings can effectively improve the indoor thermal environment and reduce the annual energy consumption of buildings in severe cold area and cold area.In this paper,the structure of insulation window filled with silica aerogels and PCMs is proposed,and the research method of thermal performance is developed.The energy consumption,economic benefit,investment recovery period and environmental protection benefit are evaluated.The results can provide scientific reference for the application and development of insulation window filled with silica aerogels and PCMs.