Research On A Novel Point-focusing Total Reflection Photovoltaic Concentration System

As the issue of clean energy becomes increasingly urgent,solar energy has great advantages over other energy sources,due to its huge resource reserves and no pollution.Therefore,focusing on the development and utilization of solar energy has become an important trend.Because of the complexity of the structure of the traditional solar energy concentrating with lightguide,the cost of electric power generation is high,and the efficiency of light is low.This article applys the theory of non-imaging optics,designs two sets of new point-focusing photovoltaic concentration systems based on the traditional solar concentrations.The new concentration systems have both high concentration ratio and high efficiency.The main work is as follows:First,a compound parabolic(CPC)point-focusing total reflection photovoltaic concentrator is designed based on the theory of edge rays and the law of refraction and reflection of rays.The concentrator includes dual-parabolic collector array and a CPC-type lightguide.Light converges through the dual-parabolic structure and is coupled into the lightguide,and then converges on the end side of the lightguide via the CPC structure to achieve point-focusing.The performance of the concentration ratio and efficiency are then analyzed when using varied parabolic coefficient,height of the collector,and CPC design parameters of the system.On the one hand,the design of the CPC-type point-focusing total reflection photovoltaic concentrator can keep the condensing system with a high efficiency under the condition of a high geometric concentration ratio.On the other hand,the dualparabolic structure and CPC structure are relatively easy to process,therefore the manufacturing cost of the system is reduced.In order to improve the efficiency of design,a fan-shaped point-focusing total reflection photovoltaic concentrator is proposed.Compared with CPC type point-focusing total reflection photovoltaic concentrator,the dual-parabolic concentrating module are cut,trimed and arrayed into a fan shape,and accordingly the lightguide is designed as a fan shape,which produces a point-focusing condenser at the beginning of the design.There is no the secondary converging element.Therefore,this design is simpler and more efficient in design efficiency,and is suitable for general point-focusing photovoltaic concentration systems.In order to research the influence of the central angle of the fan shape on the focusing performance,fanshaped point-focusing total reflection photovoltaic concentrators are tested and analyzed under different conditions of the central angle of the fan.The relative position error between the collector array and the lightguide in the photovoltaic concentration system is analyzed and researched.Finally,related modules are processed in two new types of point-focusing total reflection photovoltaic concentration systems,and test platforms for concentration systems are built respectively.While the geometric concentration ratio varies with the number of collectors,the effects of wavelength and weight on the efficiency are researched,and the feasibility and accuracy of two design methods of point-focusing concentration systems are verified.The two new point-focusing total reflection photovoltaic concentration systems proposed in this paper have reasonable design methods,concentration ratio and concentration efficiency can reach up to 800 and 83% respectively,which provides some ideas for the design and development of hybrid solar concentrators.