Experimental investigation of porous disc enhanced receiver for solar parabolic trough collector

Abstract

In this article, experimental investigation of 15 m2 solar parabolic trough collector with porous disc enhanced receiver is carried out according to ASHRAE 93-1986 test procedure. Six different receiver configurations are developed and investigated to compare their performance. The performance of solar parabolic trough collector with two conventional and four porous disc receivers is characterized in terms of time constant, collector acceptance angle, peak performance, daily performance and heat loss tests. The tests are carried out for wide range of flow rates (100 L/h–1000 L/h) and weather conditions. Based on experimental investigation, the time constant of the parabolic trough collector is varied from 70 s to 260 s for different receiver configurations. The collector acceptance angle is determined for both un-shielded tubular receiver (USTR) and shielded tubular receiver (STR) as 0.58° and 0.68° respectively. The collector efficiencies are obtained as in the range of 63.9%–66.66% under ASHRAE standard test condition. Off-Sunset heat loss test is conducted to determine the steady state heat losses from the parabolic trough collector receiver. The heat losses from the parabolic trough collector are in the range of 455 W/m2–1732 W/m2 for average fluid temperature of Tamb + 30 °C. Stagnation temperature of the collector is obtained as 258 °C and 312 °C respectively for USTR and STR corresponding to direct normal insolation (DNI) of 786 W/m2 and 761 W/m2. Based on the above analysis, the porous disc enhanced receiver improves the performance of the parabolic trough collector significantly and it can be used effectively for process heat applications.