A Theoretical Study of the Energy‐Harvesting Properties of Nontracking Semicircular Concentrating Troughs

Abstract

The objective of this paper is to give a theoretical appraisal of the light harvesting attributes of nontracking concentrating troughs of a simple semicircular cross section. Emphasis is placed on the importance of the geometry of the caustic exhibited by reflection from a semicircular surface. The efficacy of various placings of the absorber tube is assessed using the method of ray tracing calculations. Utilization of the caustic geometry leads to troughs of optimized width which can capture 100% of the incident radiation normal to the fixed trough aperture. Troughs of different optimized widths (in units of the diameter of planar or cylindrical absorbers) are examined. The major results are to show that these troughs, with fixed concentration ratios, have universal properties which scale with the absorber size and that a favorable comparison is made with the ubiquitous compound parabolic concentrator of the same order of magnitude in size. This work suggests that there is further scope for the optimized design and testing of semicircular troughs.