Performance evaluation of latent heat energy storage in horizontal shell-and-finned tube for solar application

Thermal energy storage plays a key role in improving the efficiency of solar applications. In this study, the energy storage behavior (melting or charging) and energy removal process (solidification or discharging) are investigated in the presence of paraffin wax as a phase-change material (PCM) in a horizontal shell-and-finned tube. The horizontal shell-and-finned tube comprises 24 and 48 radial fins for investigation in the laminar regime. The effect of external fin surface area on the heat transfer between the PCM and heat transfer fluid (HTF), distilled water, was studied. To realize this issue, the PCM charging and discharging times at different Reynolds number of HTF were investigated in the presence of both series of fins (24 and 48 fins). Along with a significant improvement in heat transfer with higher number of fin, the results concluded that a change in the HTF flow rate presents more influence on the PCM charging process as compared with discharging process. Also, the charging time was reduced 58 and 76 % by increasing HTF flow rate and fins density, respectively.