The thermo-hydraulic performance of a parabolic trough collector with helically corrugated tube

Abstract

The parabolic trough collectors (PTCs) are widely used to produce thermal energy. The thermal performance enhancement of PTCs draws considerable attention. Corrugated tubes are extensively used in engineering applications, which are successful in increasing heat transfer and decreasing the size of the system. Despite the high efficiency of helically corrugated tubes, not much work has been done to determine the effect of them in a PTC. Consequently, in this experimental study, the effects of corrugated tubes at different pitch ratios on the performance of the PTC are surveyed. For this aim, a PTC was manufactured, and the effects of three different corrugated absorber tubes were experimentally investigated based on the standard of ASHRAE 93 (2010). The Reynolds number changed from 624 to 4757. The results depict that the PTC using corrugated tubes has the highest performance in the transitional regime. The maximum Nusselt number augmentation was 4.2 at the pitch ratio of 0.12, and roughness height ratio of 0.06. Also, the thermal performance factor has an increase of about 26%–176%.