Performance enhancement of latent heat thermal energy storage system using fins nanoparticles and ultrasonic vibrations

Abstract

Thermal energy storage utilising phase change materials (PCMs) newlinehas sparked the interest of researchers over the last few decades due to its newlinesalient features like high storage density, isothermal heat transmission, newlinechemical stability, and so on. Despite a large number of quantitative studies, newlinethe implementation of PCM-incorporated latent heat thermal energy storage newlinesystems (LHTESS) in real-time applications has been limited due to its newlineunfavourable properties like poor thermal conductivity, phase segregation, newlineetc. This motivates the scientific community to investigate the use of various newlineheat transfer enhancement techniques, including incorporation of fins, newlineinsertion of metal structures/porous materials, dispersion of high conductive newlinenanomaterials, etc. newlineIn this work, novel quadruple helical fins are designed for shell and newlinetube LHTESS and the thermal performance enhancement is compared with newlinethat of conventional longitudinal fins. The role of these two fin geometries on newlinethe melting and solidification behaviour of paraffin wax is analysed newlinenumerically and the numerical model is validated with the experimental newlineresults. For comparative evaluation, the geometrical properties of quadruple newlinehelical fins are fixed in such a way that the volume occupied by quadruple newlinehelical fins and longitudinal fins is the same. The melting time is reduced by newline85% with quadruple helical fins as compared to the system without fins, and newlinelongitudinal fins could exhibit an 80% reduction in melting time. The newlinereduction in solidification time is found to be 68% (quadruple fins) and 63% newline(longitudinal fins). Further, quadruple fin arrangement is found to generate newlinevortex flow in liquid PCM during melting and, hence, enhanced natural newlineconvection is observed when compared to the system having longitudinal fins. newline newline