Study on Heat Collection Characteristics of Linear Fresnel Lens Solar Concentrator in Tensile Deformation Causing Zoom
The linear Fresnel lens is expected to be widely used in solar concentration fields because of its high optical efficiency and lightweight.However,the focal length of a linear Fresnel lens will become shorter when light tilt incidence occurs,resulting in short daily working hours and low energy collection efficiency of the Fresnel lens,which hinders its large-scale applications.In this regard,this paper presents a linear Fresnel lens made of transparent elastic material,whose focal length can be adjusted by tensile deformation.During light tilt incidence,the shape of prisms of the Fresnel lens is changed by mechanical stretching to adjust the angle of refraction of light to compensate for the change in focal length.The mechanical and optical joint simulations are carried out to study the concentrating behavior of the linear Fresnel Lens during tensile deformation.An exemplary linear Fresnel lens with an aperture width of 200 mm and focal length of 360 mm was designed and experimental studied.The test results indicate that the method of tensile deformation causing zoom can effectively increase the daily working hours of the linear Fresnel lens by more than 2 h.Additionally,the all-day experimental results indicate that the effective daily working hours of the linear Fresnel lens is 6.5 h,during which the average heat collection efficiency exceeds 0.6.
linear Fresnel lensstretch zoomtilt incidencefocal length changesolar concentra-tion
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