Study On Hollow Optical Fiber For Solar Energy Transmission And Design Of Concentrator

This paper describes an in-depth study on fabricating membrane of PMMA/Ag (Polymethyl Methacrylate)leakage hollow optical fibers which have large aperture and low transmission attenuation.Relative to conventional hollow optical fiber for transmission of CO₂ laser,this type of fiber transmits 300-1800 nm wavelength of the sunlight.So the thickness of the optical film in the design and material selection has some difference.This band of energy accounting 85%of solar radiation energy, through low-loss hollow optical fiber,transmits to indoor lighting.To a certain extent, it can solve the energy crisis problem,but also be beneficial to the environment.Through analysis and comparison,a choice of quartz glass capillary has be done as hollow optical fiber matrix,the inner diameter of 2 mm;through theoretical calculation and the choice of materials to determine the coating thickness is 0.2μm high reflectivity silver membrane,then plating thickness of 90 nm PMMA dielectric layer;by plating silver membrane and PMMA dielectric thin films on quartz substrates,overall optimization of manufacturing parameters can be determined in the vertical coating film machine of hollow optical fiber.The optimum response condition is that the reaction temperature was controlled in 17℃,shading the light, the pH value controlled in pH=8～9,in the return a few nitric acid joined to original state fluid as catalyst,a few polyethylene glycol 4000 as stabilizer,moreover,a few ethyl alcohol in the return to original state fluid to be possible to reduce surface tension of the solution,favoring the response advance.The silver complex ion density is 0.1mol/L,the reaction time is 1min,the current capacity is 18ml/min,the reaction time decides as 1～2min;In the capillary vessel preparing the PMMA dielectric medium coating is not big difference on the substrate preparation craft,mainly lying in the current capacity control.Through the experiment comparison,determined that take the 0.4%PMMA acetone solution,the current capacity as 50 ml/min,the time is 30s.Solar collector is based on the principle of focusing parabolic mirror to make the parallel incident solar energy together into a point light source and then transmit into a hollow fiber.This paper has a scientific design in the structure and optics for high-precision paraboloidal solar collector.It will get a good match in the concentration and spot diameter with the hollow optical fiber.Based on the revolving parabolic mirror's collection parameter,has chosen the caliber D=250mm,the edge half-angleφ=45°parabolic mirror.This parabolic mirror core facula diameter is 1.2mm,the sunlight degree of enrichment is 31218;The biggest collection efficiency's facula diameter is 2mm,average sunlight concentration 15609. Considered this design take collection efficiency primarily,chooses the hollow optical fiber diameter as 2mm.Had determined through the theoretical calculation the plane reflector's diameter is 15mm,the distance of optical fiber's input end between plane mirror is h=6.7mm.By using similar solar spectrum xenon light source tests and analyses transmission performance of the PMMA/Ag leakage hollow optical fiber.By measuring the energy input and output,according to formulas,the straight loss and bending loss can be calculated.The fiber and collector assembly,testing the efficiency of the whole system and the transmission loss,comprehensive evaluation of the study design.With the traditional use of solar energy devices,compared to the device does not require energy conversion,high efficiency,simple structure,focus can be achieved after long-distance efficient solar energy transmission.