Numerical Investigation of phase transition in different latent heat storage systems in the presence of natural convection and porous media

Abstract

Securing a reliable supply of energy is critical given the ever-increasing demand for energy and the challenges posed by a growing population. Latent energy storage is being introduced as one of the most efficient solutions to harness renewable and waste energy and ensure a constant supply. The phase change material (PCM) in this type of energy storage suffers from low responsiveness, which slows down the industrialization of latent storage. This study succinctly identifies the influencing factors that affect the efficiency of PCM-based latent energy storage, including fluid temperature, the role of natural convection and the benefits of porous media. It also provides new insights through comprehensive configuration analysis, ultimately contributing to the understanding of the field and addressing sustainable energy demands. For the numerical computations, enthalpy-porosity methodology via ANSYS Fluent 18.2 is employed a rigid grid for precise dual-phase simulation. The working fluid temperature is of similar importance for three types of units, as an improvement of 22% has been obtained by increasing the inlet temperature by 5 degrees, while the pipe model has benefited from an improvement of 26% under the same condition. The Triplex Tube Heat Exchanger (TTHX) outperforms the other units in all scenarios, as the heat transfer surface of this type is greater than that of its counterparts. Natural convection phenomenon is most effective in the pipe model, as its absence slows the melting rate by 236%. The inclusion of porous media produced on average 93% faster systems due to the additional heat transfer surface, although it suppressed the gravitational movement.