Experimental investigation of hybrid vacuum tube solar water heater/parabolic concentrator integrated with phase change material and nanofluid as HTF simultaneously; energy and exergy assessments

ABSTRACT

Solar water heaters suffer from fluctuating hot water production due to unpredictable weather changes throughout the day. In this study, the hybrid configuration of a vacuum tube solar water heater with a parabolic solar concentrator, in conjunction with the application of paraffin as a phase change material, is employed as a novel approach to address this problem. Furthermore, the study investigates the utilisation of a nanofluid (0.05%, 0.1%, and 0.2% mass) containing Al₂O₃ and ZnO nanoparticles dispersed in water-ethylene glycol (base fluid) as the medium fluid to enhance thermal performance. The experimental results revealed that the utilisation of 0.2% mass ZnO and Al₂O₃ nanofluids led to a considerable increase of 10.74% and 7.25%, respectively, in the maximum reservoir temperature. This resulted in a respective average thermal efficiency improvement of 41.6% and 33.9% compared to the base fluid. Furthermore, the maximum exergy efficiency of the system exhibited a significant increment of 54% and 40.1% compared to the base fluid. Moreover, the incorporation of phase change material in the system effectively minimised temperature fluctuations.

KEYWORDS:

• Solar water heater
• evacuated tube
• parabolic concentrator
• nanofluid
• phase change material
• hybrid

Disclosure statement

No potential conflict of interest was reported by the author(s).