Performance Evaluation of Multiple Helical Tubes as a Receiver for Solar Parabolic Trough Collector

Abstract

Solar parabolic trough collector consists of a parabolic reflector with a central receiver at a focal point through which heat transfer fluid is passed. Parabolic trough collector is used mostly in solar thermal power plants for generating electricity. This paper describes the experimental results of two straight tubes wrapped over each other to form a helically shaped receiver. The receiver was tested with aluminium material with and without black paint over it. Also, the helical tube receiver was tested with a glass cover over it, at two different mass flow rates and, with and without manual tracking. The tested instantaneous thermal efficiency ranges from 31.26% to 45.28% and the overall thermal efficiency ranges from 14.9% to 31.41% during the experimental period. The instantaneous thermal efficiency increased by an average of 1.32 times for unpainted receiver and 1.36 times for black painted receiver with the increase in mass flow rate. By tracking the parabolic collector according to sun’s position, there is an average increase in instantaneous thermal efficiency by 1.1 times for unpainted receiver and 1.04 times for black painted receiver. The paper further reveals that the use of multiple helical tubes as a receiver for parabolic trough collector increases the overall efficiency of the collector in a substantial manner.