Investigations of thermo-structural instability on the performance of solar parabolic trough collectors

Abstract

Solar parabolic trough collectors are a mature technology among other concentrated solar power technologies. However, improvements in the structural stability and the accuracy in the shape of the reflectors and the receiver are essential for making them at par with other solar power technologies. A methodology is proposed in the present work for the investigations of the combined effect of the thermo-structural instability in the reflector and the receiver on the performance of trough collectors. The circumferential temperature distribution and wind loads lead to bending in the receiver and the reflector, respectively. The analysis involves temperature and bending effects at four mass flow rates of 3 kg/s, 6 kg/s, 9 kg/s, and 18 kg/s in the absorber tube and three slope errors 1 mrad, 2 mrad, and 3 mrad at the reflector. The optical efficiency decreases from 86% to 67.24% for the bending from 0 mm to 10 mm, and the loss is as high as 17.7% for 3 mrad and 10 mm deflections at the reflector and the receiver, respectively. The present study shall help in the design and condition monitoring of the trough collectors.