| This paper choose paraffin and glass roof filled with paraffin wax as research object,the transmission spectrum of glass roof filled with paraffin wax was measured,and optical properties of paraffin was obtained.Photo-thermal performance of glass roof contained paraffin was analyzed by combining experiment and simulation,the energy efficiency and its influencing factors was also studied.Based on the climate data of Daqing to optimize the structure parameters of the glazing roof contained paraffin.The main contents of this paper are as follows:1.A constant temperature heating chamber used in UV spectrophotometer was designed,and the thermal environment in it was analyzed numerically.The transmission spectra of paraffin was measured in the range of 40~80 ?,and the optical constants of paraffin was obtained by the double-thickness method.The results show that the temperature has a ruleless effect on optical constants of paraffin.2.The experimental device for photo-thermal performance of glass structure containing paraffin was designed.The influencing factors of the glass stucturc containing paraffin on its photo-thermal performance was investigated,such as solar radiation intensity,thickness and melting temperature of paraffin.The results show that solar radiation intensity and thickness of paraffin have a significant effect on photo-thermal performance of glass structure containing paraffin,but the melting temperature of paraffin is nearly making no difference.3.The heat transfer experiment device of glass roof containing paraffin was built in cold area of China.Based on the outdoor climate parameters of Daqing,the temperatures of glass inner surface and indoor were measured,the effects of paraffin phase change temperature,thickness and roof slope on thermal environment of the experimental box were also investigated.The results show that paraffin phase change temperature and roof slope affect the indoor temperature and the delay of its peak temperature,the thickness of paraffin has a great influence on temperature inside the box,which is hardly affect the delay of peak temperature.4.Considering the radiation of translucent medium as source terms,the heat transfer model of glass roof containing paraffin was established,which used solidification & melting model to calculate phase change heat transfer.The heat transfer characteristics of glazing structure filled with paraffin was simulated based on Fluent software.The study found that the latent heat,absorptance and thickness of paraffin and the solar radiation intensity have great effects on heat transfer characteristics of glass structure filled with paraffin,but the refractive index of paraffin and outdoor heat transfer coefficient has weak influence on it.5.Separating the solar thermal transmission,a one-dimensional photo-thermal transfer model for glass roof contained paraffin was developed based on explicit capacity method.The computation program was written to investigate the influence of capacity,latent heat,melting temperature of paraffin and so on.The study found that the thickness of paraffin should meet the range of 9~12 mm in Daqing.The results of this paper can provide some theoretical reference and data to support the development and application of PCM-filled glass roof technology in severe cold areas. |
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