Design and experimental analysis of air heating performance of a star-shaped receiver in a non-tracking compound parabolic concentrator

Abstract

In order to find an effective way to improve the performance of the non-tracking compound parabolic concentrator (CPC), this study presents the design evaluation and performance testing of a novel star-shaped receiver with an inexpensive single-layer glass tube. The optical model of the CPC was first established with the TracePro, and the influence of the incident angle on the optical performance of the CPC and the distribution of the energy flux density in each sector of the star-shaped receiver tube were determined. The results show that the rays receiving ratio and the concentration ratio of the CPC both decrease with the increase of the incident angle, when −13°≤α ≤ 13°, the two parameters are 84.37 % and 64.32 %, respectively. Based on this, a testing bench was set up to test the photothermal conversion performance of the CPC under actual weather conditions. The influence of the air flow velocity on the photothermal conversion performance of the CPC, the outlet temperature and air flow velocity in each sector of the star-shaped receiver tube were tested and analyzed, and the potential correlation between them is discussed. When the air flow velocity changes from 1.7 m/s to 4.7 m/s, the daily efficiency of the CPC increases from 53.26 % to 70.71 %. It is found that air flow was not distributed evenly between six sectors of the star-shaped receiver tube trough it is symmetrical, so the outlet temperature and optical contribution ratio are different between six sectors. The results of the study provide a reference direction and data support for the optimization and application of the star-shaped receiver tube in non-tracking CPC.