Experimental investigation into a parabolic solar collector with direct flow evacuated tube

Solar energy is among the cleanest and most adaptable in comparison with other renewable energy sources. Considering the request for long-term using of solar collectors, developing and enhancing the performance of these systems has become one of the main subjects. Parabolic trough solar collector (PTSC) is one of the best usual solar collectors. improving the thermal performance of PTSC concentrates several attention and different approaches are evaluated to maximize the collector thermal efficiency with a reasonable penalty in the pressure drop and energy losses. For this reason, the use of different nanofluids as working fluids, as well as the use of various absorbers (receivers) are the major challenges and techniques which are examined. Therefore, in this study, a novel parabolic trough solar collector (PTSC) using U type tube is designed and manufactured. To increase the operational temperature, evacuated tube is used and performance of the mentioned system is experimentally examined using both distilled water and CuO nanofluid as working fluids. It should be noted that, CuO is selected as nanoparticle and water as base fluid. CuO/nanofluid. Absorption spectrum results of CuO/nanofluid at different resting times by using Ultraviolet-Visible (UV-Vis) spectroscopy examined. Experimental results for the changes in three important parameters including, performance index (PI), thermal efficiency as well as pressure drop are obtained for different mass flow rates including, 1, 3 and 5 L/min and also three particle volumetric concentrations including 0.01%, 0.05% and 0.08%. The results showed that, thermal efficiency, pressure drop and PI is mostly affected and increased by mass flow rate and nanofluid volume fraction. In addition, based on the experimental results, maximum thermal efficiency and performance index are obtained respectively 71% and 1.74, corresponding in the case of nanofluid with 0.08% volume fraction and mass flow rate of 5 L/min.

Automated summary

The study developed a novel parabolic trough solar collector and experimentally examined its performance. The results showed that mass flow rate and nanofluid volume fraction have significant impacts on thermal efficiency and performance index.