A cylindrical blackbody solar energy receiver

Abstract

This paper discusses a design for a receiver appropriate Fora concentrating collector having potential application at moderate working temperatures (near 100°C) as well as at high temperatures (above 300°C). The receiver consists of an annular cylindrical tube with an aperture parallel to the axis of the cylinder. The aperture is illuminated by means of a focusing concentrator, such as a lens, and the radiation energy is scattered inside the cavity, absorbed by the walls and transmitted, as heat, to the working fluid flowing axially inside the annulus. To reduce radiative losses the tube is surrounded by a layer of a thermal insulator. Principal advantages of this design lie in exclusive use of commonly-available materials and current fabrication technology. Thermal losses are controlled by the configuration of the receiver assembly containing the working fluid, without the use of special surface coatings, vacuum enclosures, or other complex features. Projected performance of the collector is compared with other designs. A theoretical performance analysis is presented, and two specific examples pertiment to moderate and high-temperature applications, are discussed.