Stationary concentrating reflector cum tracking absorber solar energy collector: optical design characteristics

Abstract

This article presents an analysis of the optical design characteristics of a stationary reflecting/tracking absorber solar energy collector. This type of collector consists of a segment of a spherical mirror placed in a stationary position facing the sun, but having a linear absorber that can track the image of the sun by a simple pivoting motion about the center of curvature of the reflector. The optical characteristics of this system and the axial variation of its concentration ratio are developed to provide information for the engineering design and sizing of this type of solar energy collector system.

Optical and Thermal Performance Analysis of a Steady Spherical Collector with a Crescent-shaped Rotating Absorber

“…We obtain so the absorber characteristics as a truncated cone. This is also stated by Steward and Kreith 1975 [7]. By considering the half angle of the sun image projection …”

Low-Cost Solar Electricity Using Stationary Solar Fields; Technology Potential and Practical Implementation Challenges to Be Overcome. Outcomes from H2020 MOSAIC Project

“…Unlike parabolic mirrors, spherical concentrators (or solar bowls) can be fixed using a mobile receiver [8]. Hence, these systems are also known as SRTA (stationary reflector/tracking absorber).…”

Development of a solar collector with a stationary spherical reflector/tracking absorber for industrial process heat

“…The outside diameter of the coil was 75 mm, which is five times the maximal theoretical diameter. This safety factor was determined based on the optical analysis of the SRTA by Steward and Kreith (1975), which had indicated a considerably smaller (14 mm versus 75 mm) diameter possible for a perfect spherical mirror. However, in our practical mirror, the absorber diameter was determined not only by the 0.5°divergence of the solar rays but also by the imperfections of the mirror surface and the tracking system accuracy.…”

“…The optical design characteristics of the SRTA were studied in detail by Steward and Kreith (1975). A thermal performance analysis was conducted by Kreider (1975), which identified the important design parameters influencing heat losses from the absorber.…”