Fresnel Lens Characterization for Solar Concentration Efficiency

Abstract

Due to the inexpensive and light weight nature of Fresnel lenses, they are key components in many solar energy concentration systems. Thus, the ability to effectively characterize Fresnel lenses over large areas is essential to verifying their system performance and efficiency. Under high concentration, it becomes impractical to perform detailed spatial and spectral measurements under full sun conditions. We have developed a method to characterize large Fresnel lenses for concentrating solar applications. Our Lens Characterization Unit (LCU) analyzes the resultant pattern of an incident laser beam which may be scanned across the lens. Using the LCU, we can evaluate the portion of diffracted light that is concentrated on the receiver area at each point of incidence. After running initial tests and quantifying our results, we have determined that this method of lens characterization is effective for both focal point analysis and spatial distribution of the incident beam.