Analysis and design of a radial waveguide concentrator for concentrated solar thermal applications

Non-imaging concentrators based on optical waveguides have the potential to provide low cost solar collection for concentrated solar thermal applications through the elimination of moving parts and tracking structures. The primary working principle involves collection and transport of light through total internal reflection within an optical waveguide onto thermal receivers. This study explores the optical and thermal transport characteristics of radial waveguides integrated with a linear receiver. An analytical closed-form solution for the coupled optical and thermal transport of solar irradiation through a radial planar waveguide concentrator integrated with a linear receiver is developed. The effects of various design and operating parameters on the system performance, which is quantified in terms of net thermal power delivered, aperture area required and collection efficiency are discussed. Design constraints due to thermal stress, maximum continuous operation temperature and structural loading were considered to identify feasible waveguide configurations. A cost analysis is conducted to determine the preferred design configurations that minimize the cost per unit area of the radial waveguide concentrator-receiver system. Optimal design configurations that result in the minimum levelized cost of power (LCOP) are identified for thermal desalination and concentrating solar power generation applications.