ABSTRACT
Latent heat energy storage system employing phase change material forms the backbone of energy storage techniques with high energy storage density. But the low thermal conductivity of PCMs always poses a hindrance. In this chapter, the geometrical variations providing eccentricity to the inner heat transfer fluid tube are numerically studied. Enthalpy Porosity formulation is applied for the simulations of the phase change of honeybee wax. Vertical eccentricity with magnitudes 20 mm and 40 mm upwards and downwards is provided to the inner tube. Contours of temperature, liquid fraction, and velocity are represented, and performances are compared by studying the plots of liquid fraction, average temperature, and energy stored with time. The results have shown that the downward eccentricity increases the melting rate but decreases the rate of solidification and the upward eccentricity decreases both melting and solidification rate compared to the concentric inner tube case. The percentage increase of the solidification time is less in the upward direction compared to the same amount of downward eccentricity. The concentric inner tube case is the most efficient case for a complete cycle compared to other cases considered.
