The capture of solar radiation by troughs concentrating radiation onto absorbing cylinders placed in them is fundamental to applications in many industrial and urban environments. The efficiency of the collection of solar radiation depends strongly upon the design of the concentrating trough. In this article, the design of three types of concentrating troughs in their solar radiation capture properties is compared. The simplest design of a trough, a semi‐circular form, has been largely ignored at the expense of troughs of compound parabolic or pure parabolic form. The methodology employed in the comparison is a numerical ray‐tracing technique in which the percentage of incident radiation captured by the absorbing cylinder embedded in the trough is calculated. First, troughs which are fixed and so do not track the sun’s movement over the day are considered. A trough of semi‐circular design is contrasted with the ubiquitous troughs of compound parabolic concentrator (CPC) form. Then the light‐gathering characteristics of tracking parabolic troughs are compared with those of the semi‐circular form. The calculations show that a truncated semi‐circular trough (SCT) can give the same 100% capture of incident radiation as a CPC or truncated parabolic trough. The SCT does not require access to sophisticated manufacturing techniques.
Ratismith et al. (Thu,) studied this question.