Experimental study of a parabolic trough solar collector with flat bar-and-plate absorber during direct steam generation

The present work aims at investigating an innovative flat aluminum absorber for process heat and direct steam generation in small linear solar concentrating collectors. After defining its optimal width through a Monte Carlo ray-tracing analysis, this absorber has been manufactured with the bar-and-plate technology, including an internal offset strip turbulator in the channel. This technology is cost-effective and extremely flexible, allowing to easily adapt the geometry of the absorber to different reflecting optics configurations. It has been mounted on an asymmetrical parabolic trough concentrator to form a solar collector with a concentration ratio of 42, which has been experimentally investigated. In particular, a new test procedure is presented, applied and validated to characterize the thermal performance of the collector during steam generation. The results show that a promising overall thermal efficiency of 64% at 0.160 K m2 W−1 can be achieved with negligible pressure drop.