Enhancing the Performance of Latent Heat Thermal Energy Storage System by Optimising the Design Geometry

Abstract:

Latent Heat Thermal Energy Storage (LHTES) systems are increasingly recognised as effective solutions for mitigating the intermittency of solar thermal energy. This study presents a comprehensive numerical investigation into the effect of fin geometry on the thermal performance of LHTES units designed for solar applications. Five configurations were examined: a baseline unit and four enhanced designs incorporating longitudinal, V-shaped, T-shaped, and triangular fins. The triangular fin geometry was further optimised by varying the number of fin patterns—two to five—across the heat transfer surface. All configurations employed paraffin wax (RT82) as the phase change material (PCM), thermally enhanced with copper particles to improve thermal conductivity. A high-fidelity 3D model was developed in ANSYS Fluent to simulate the melting process within a triplex-tube heat exchanger under natural convection conditions. The results revealed a strong dependence of melting performance on fin geometry. Notably, the five-pattern triangular fin configuration achieved the shortest melting time (78 minutes), representing an 82% reduction compared to the baseline. These findings underscore the critical role of fin optimisation in improving heat transfer and overall efficiency of LHTES systems.

• Periodical: Diffusion Foundations and Materials Applications (Volume 39)
• Pages: 177-192
• DOI: https://doi.org/10.4028/p-39Qeub
• Online since: January 2026
• Authors: Abdul Khadir Mohamad Syafiq*, Adel Nasser, Mohd Haidiezul Jamal Bin Ab Hadi, Noorhafiza Muhammad, Ahmad Zulhusni Bin Mahmad Zuki
• Keywords: Latent Heat Thermal Energy Storage, Phase Change Material, Triplex Tube Heat Exchanger

References

[1] IEA. (2023). World Energy Outlook 2023. International Energy Agency.

[2] REN21. (2023). Renewables 2023 Global Status Report. REN21 Secretariat, Paris.

[3] Zhang, Y., et al. (2023). "Optimisation strategies for thermal energy storage systems in renewable energy applications: A review." Renewable and Sustainable Energy Reviews, 176, 113232.

[4] Hasan, A., et al. (2023). "Recent progress in solar thermal energy storage technologies." Applied Energy, 345, 120296.

[5] Sharma, R. K., et al. (2022). "Latent heat thermal energy storage systems for solar applications: Recent trends and challenges." Energy Reports, 8, 3371–3385.

[6] Khodadadi, J. M., & Hosseinizadeh, S. F. (2022). "Thermal conductivity enhancement in phase change materials for thermal energy storage: A review." Renewable Energy, 201, 68–90.

DOI: 10.1016/j.rser.2010.08.007

[7] Mahdi, J. M., et al. (2023). "Numerical evaluation of paraffin wax melting in a shell-and-tube thermal storage unit with helical fins." Applied Thermal Engineering, 222, 119936.

[8] Al-Abidi, A. A., et al. (2022). "Review of finned tube heat exchangers in PCM-based thermal energy storage systems." Renewable and Sustainable Energy Reviews, 160, 112296.

[9] Li, W., et al. (2023). "Thermal performance enhancement of multiple tubes latent heat thermal energy storage system using sinusoidal wavy fins and tubes geometry." International Journal of Heat and Mass Transfer, 208, 124114.

DOI: 10.1016/j.applthermaleng.2024.122750

[10] Eltaweel, A., et al. (2024). "The effect of fin geometry on the thermal performance of a conical latent heat thermal energy storage system." Case Studies in Thermal Engineering, 47, 103253.

[11] Al-Abidi, A. A., Mat, S., Sopian, K., Sulaiman, M. Y., & Mohammad, A. T. (2014). Experimental study of melting and solidification of PCM in a triplex tube heat exchanger with fins. Energy and Buildings, 68 (PARTA), 33–41. https://doi.org/10.1016/j.enbuild. 2013.09.007

DOI: 10.1016/j.enbuild.2013.09.007

[12] Mahdi, J. M., et al. (2023). Numerical evaluation of paraffin wax melting in a shell-and-tube thermal storage unit with helical fins. Applied Thermal Engineering, 222, 119936.

[13] Al-Abidi, A. A., et al. (2022). Review of finned tube heat exchangers in PCM-based thermal energy storage systems. Renewable and Sustainable Energy Reviews, 160, 112296.

[14] Liu, X., et al. (2023). Effect of eccentricity and V-shaped fins on the heat transfer enhancement of latent heat thermal energy storage units. Case Studies in Thermal Engineering, 42, 103039.

[15] Khalid, M., et al. (2022). Evaluation of T-shaped fins with a novel layout for improved melting of phase change materials in vertical triple-tube heat exchangers. Frontiers in Energy Research, 10, 947391.

[16] Rahman, M. M., et al. (2024). Investigation of the impact of triangular shape fins to enhancing the melting performance in a triplex-tube thermal energy storage system. International Journal of Heat and Mass Transfer, 213, 124589.

[17] Mostafa, A. M., et al. (2021). Impact of innovative fin combination of triangular and rectangular fins on the thermal performance of a latent heat thermal energy storage system. Case Studies in Thermal Engineering, 27, 101268.

DOI: 10.1016/j.csite.2021.101339

[18] Eltaweel, A. A., et al. (2024). Thermal performance of composite fin designs for PCM melting in cylindrical heat exchangers. Energy Conversion and Management, 293, 117631.