Experimental investigation on the influence of nanofluids used as heat transfer fluid in phase change material based thermal energy storage system

The present study investigated the enhancement of energy conservation under the principles of pure substances that exercise phase change throughout charging and discharging processes. This work primarily focused on the thermal energy storage system, where the working medium charges the PCM’s namely (Paraffin wax u0026 stearic acid) that is normally encapsulated in spherical balls. The potentiality in charging of working medium was examined upon blending HTF (heat transfer fluid) with four nano-particles (Al2O3, CuO, TiO2 u0026 MgO). Several volume concentration levels (0.2%, 0.5% and 0.8%) were considered for afore mentioned nanoparticles under the influence of assumed flow rates (2l/min, 4l/min and 6l/min). The experiments were carried out with various nano-fluids used as HTF for different flow rates and volume concentrations. The results showed that there is a considerable amount of reduction in charging time, in case of 6 l/min, 0.8% volume concentration and PCM as Paraffin wax, around 27.22 % for TiO2 nano-fluid, 36.66% for Al2O3 nano-fluid, 40.90% for CuO nano-fluid and 63.63% for MgO nano-fluid, and PCM used as Stearic acid, around 26.31 % for TiO2 nano-fluid, 42.10% for Al2O3 nanofluid, 47.36% for CuO nano-fluid and 68.42% for MgO nano-fluid, when compared with the conventional HTF, water. From the results, it was observed that the effect of particle concentration played an important role in the heat transfer process. During the discharging process, 210 liters of hot water withdrawn with paraffin wax used as PCM and 198 liters of hot water withdrawn with stearic acid used as PCM.