Sustainable Thermal Performance Enhancement of a Rotating Shell-And-Tube Latent Heat Thermal Energy Storage Unit: Experimental and Numerical Investigations

Latent The use of latent heat thermal energy storage units for efficient energy recovery has been established widely, but its efficiency is still restricted by low thermal conductivity of phase change materials. In this work, an experimental and numerical investigation on the solidification process of paraffin wax in a horizontal shell-and-tube latent heat storage unit with stationary and rotating operation modes was performed. The evolution of the temperature field was measured in three different axial directions and three circumferential positions (0°, 45°, and 90°) in the case of both stationary and rotating operations with a flow rate of 2 L/min. At the same time, a three-dimensional numerical model of the solidification process was developed in ANSYS Fluent based on the enthalpy-porosity approach, and the Boussinesq approximation was used. It was found that the solidification process occurred radially from the inner pipe towards the shell, and the bottom part solidified faster than other areas due to thermal stratification. Rotational movement accelerated the solidification process, enhanced the temperature uniformity, and decreased the thermal resistance in the PCM layer. In the case of a flow rate of 2 L/min, the maximum heat gain was equal to 1117.8 kJ, and the total amount of energy. These numerical results agreed well with the experimental and benchmark results, which verified the reliability of the proposed model. These results clearly show that rotational movement is a successful enhancement method that can enhance the discharge process in the latent heat thermal energy storage system. Overall, this research shows that rotational movement is indeed a valid enhancement technique in the latent heat thermal energy storage system especially in terms of achieving faster discharge and thermal uniformity.