Experimental and numerical investigations with multifunctional heat transfer fluid to evaluate the performance of a thermal energy storage system

Abstract

In the upcoming decades, concentrated solar power (CSP) technology is expected to be one of the most promising methods of producing electricity.Along with the reduction in energy waste coupled with an increase in efficiency, the thermal energy storage (TES) systems are vital in refining the dependability and efficacy of the energy infrastructure and in reducing gap between supply and demand. This study aims to evaluate a parabolic trough collector by means of experimental investigation and mathematical modelling. Nanofluid is employed as an energy absorption material and transport medium from concentrating tube to storage tank. At consistent flow rate of 3.0 L per minute, a comparative evaluation is conducted between water and ZnS/ water-quantum dots at different volume concentrations (0.1, 0.2, 0.3, and 0.4 %). Heat exchanger-delivered sensible heat, thermal efficiency, heat removal factor, and energetic efficiency are used to examine the qualitative and quantitative performance of the system. The ZnS/ water-quantum dots ratio of 0.3 % (wt%) has been found to yield the maximum thermal and energetic efficiencies. At a solar intensity of 1210 W/m2, the highest thermal efficiency of 57.81 % is reflected by the experimental observations. At the same intensity, there is a 20.63 % increase in the energy efficiency. The charge and discharge of phase-changing material (PCM) are highly influenced by the flow rate of heat transfer fluid (HTF). By increasing the HTF flow rate from 1 to 3 L per minute, the solidification and melting times are shortened by 30 % and 10 %, respectively. This study emphatically reflects a high potential of employing nanofluid in TES to enhance the performance of energy infrastructure coupled with energy waste reduction.