Investigation of solar collector system with turbulator considering hybrid nanoparticles

M. Sheikholeslami and Seyyed Ali Farshad

Renewable Energy, 2021, vol. 171, issue C, 1128-1158

Abstract: In this article, six-lobed absorber tube equipped with combined turbulators was investigated. To enhance the productivity of solar unit, hybrid nanoparticles were added in to working fluid. Helical coil and twisted tape have been employed together. For evaluating the thermal behavior and exergy loss, average solar flux were imposed in boundary condition. Also, variable heat flux was applied to evaluate the thermal efficiency including air gap for solar system. Homogeneous model for hybrid nanomaterial was utilized and outputs were presented to analyze the impact of changing operating fluid. Selecting six-lobed tube instead of circular tube leads to better cooling performance and lower exergy loss. When Re = 10000, convective coefficient augments about 3% while exergy drop declines about 5.198% with using six-lobed tube. Insertion of twisted tape for lower Re leads to augmentation of h by 1.666% and reduction of exergy drop about 1.828%.To scrutinize the influence of width ratio and (w˜) and revolution number (n˜) for coil insert, exergy drop and friction factor values in form of bar chart were presented. Velocity augments with rise of both factors and impingement of fluid with wall increases which provides higher pressure drop and lower exergy drop. Exergy loss decreases about 8.671% and 6.286% with augment of n˜and w˜when Re = 5000. Owing to nice attributes of hybrid nanofluid, not only convective flow augments but also exergy loss reduces by adding such particles. Dispersing nanoparticles can enhance the convective flow about 9.096% and 8.438% for circular tube and six-lobed tube with turbulator, respectively. Also, exergy loss for six-lobed tube with turbulator reduces about 8.562% with adding hybrid nanomaterial. Replacing, six-lobed tube with turbulator instead of circular tube leads to reduction of exergy drop about 17.907% while convective coefficient augments about 12.719%. Augmenting solar irradiation enhances the thermal efficiency about 180.24% and outlet temperature rises from 293.2 K to 293.36 K when Re = 5000.

Keywords: Solar irradiation; Six-lobed tube; Hybrid nanoparticle; Exergy; Helical coil (search for similar items in EconPapers)
Date: 2021
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (7)

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Persistent link: https://EconPapers.repec.org/RePEc:eee:renene:v:171:y:2021:i:c:p:1128-1158

DOI: 10.1016/j.renene.2021.02.137

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