Refractive Secondary Concentrators for Solar Thermal Systems

High-throughput, non-imaging, secondary concentrating optics that utilize refraction and total internal reflection are undergoing development for use in conjunction with advanced primary solar concentrators to provide solar thermal energy for space applications. This development is prompted by (1) a need to concentrate sunlight by factors of as much as 104 to satisfy design and operating requirements for some advanced solar thermal systems and (2) the impracticality of fabricating primary concentrators with sufficient precision to afford such high concentration ratios by themselves. Figure 1 illustrates the operation of a refractive secondary concentrator.