| With the social progress and development,human's demand for energy is growing.The reserve of traditional energy resources.)has been unable to support the energy supply of social development for a long time,and excessive exploitation and use of fossil energy has caused serious damage to the environment.Therefore,people began to look for some clean and effective new energy.Solar energy is favored by people for its superiority,such as being easily obtained,renewable and zero pollution etc.Although solar energy resources are widely distributed.the density of energy flow on the earth's surface is low,So it is difficult to obtain a high temperature of heat collection by direct utilization,Therefore,the composite parabolic concentrator(CPC)is widely recognized by advantages of its simple structure and high efficiency.The standard compound parabolic concentrator(S-CPC)cannot achieve the synchronous improvement of the half-acceptance angle and the geometric concentrating ratio.To solve this problem,this paper offered a novel type of solar composite parabolic concentrator with synchronous improvement in original acceptance angle and concentration ratio(IAR-CPC)and the surface construction,model validation,optical characteristics and lighting performance of IAR-CPC were studied.The main contents of the study are as follows:(1)Based on the edge-ray theory,a novel type of surface structure model of concentrator is constructed,and its surface mathematical model is obtained by the principle of differential equation.IAR-CPC surface model is printed by 3D printing technology.There is little error of printing model,and the maximum relative error value is 0.61%.The shape of the reflecting surface is verified by the IAR-CPC model printed by 3D.The further analysis of IAR-CPC structure based on the mathematical model of surface shape shows that the matching state between the surface shape and the absorber can be ideal by adjusting the tangent angle on the premise that the surface shape of the reflecting surface is not truncated.Moreover,the angle of IAR-CPC surface parameters and the change of surface structure are more flexible,which makes IAR-CPC have better plasticity than S-CPC.(2)Based on the geometric meaning of the surface mathematical model,the parameter equations of the initial acceptance angle and the geometric concentration ratio of the optical characteristic parameters are derived and obtained.The feasibility of synchronous improvement of the two parameters is proved from the functional characteristics.The results show that under the same aperture width and absorber size,the acceptable angle of IAR-CPC is 17.56% higher than that of S-CPC through the numerical solution and comparison of the acceptable angles of IAR-CPC and S-CPC.(3)Based on the Monte Carlo Ray-Trace,the optical performance of IAR-CPC and S-CPC under ideal conditions are obtained and compared.The results show that the average optical efficiency of IAR-CPC is 4.32% higher than that of S-CPC under the same aperture width,absorber size and material characteristics.Furthermore,the energy density distribution on the surface of the two circular absorbers was studied.The results show that the energy flux density on the surface of IAR-CPC absorber is more evenly distributed than S-CPC.(4)Taking the all glass solar vacuum tube with 58 mm as the circular absorber,the surface models of IAR-CPC and S-CPC are constructed.Combining with the separation of solar directing and diffusion and the data of daily radiation of local typical meteorological year,the annual of collect daylight by two kinds of CPC heat collection system are calculated,The result shows that the total radiation collected by IAR-CPC heat collection system is higher than that of S-CPC heat collection system,and the average improvement ratio is 1.57%.At the same time,the monthly total amount of solar radiation energy collected by IAR-CPC heat collection system can meet people's psychological needs and actual needs of life in this season. |
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