Internal and external fin heat transfer enhancement technique for latent heat thermal energy storage in triplex tube heat exchangers

The importance of latent heat thermal energy storage is significant in contrast to sensible energy storage because of the large storage energy densities per unit mass/volume at nearly constant thermal energy. In this paper, heat transfer enhancement technique by using internal and external fins for PCM melting in a triplex tube heat exchanger (TTHX) was investigated numerically. A two-dimensional numerical model is developed using the Fluent 6.3.26 software program, and pure conduction and natural convection are considered in the simulation. The number of fins, fin length, fin thickness, Stefan number, TTHX material, and the phase change material (PCM) unit geometry in the TTHX are found to influence the time for complete melting of the PCM. Experiments were conducted to validate the proposed model. Simulated results agree with the experimental results. The computational results show that case G (8-cell PCM unit geometry) achieved a shorter time in completing the melting of the PCM, the total melting time is decreased to 34.7%.