Thermal Performance Analysis of a Triple-Tube Heat Exchanger with Internal and External Conductive Connections

Kuihua Fu

doi:10.62051/ijmee.v8n3.08

Authors

Kuihua Fu

DOI:

https://doi.org/10.62051/ijmee.v8n3.08

Keywords:

Triplex-tube Heat Exchanger, Phase Change Material, Heat Transfer Enhancement, Conductive Connection, Melting and Solidification

Abstract

Latent heat storage systems are limited by the low thermal conductivity of phase change materials (PCMs), resulting in prolonged charging and discharging times. To address the issues of a single heat conduction path and thermal coupling imbalance in triplex-tube heat exchangers (TTHX), this study proposes an optimized TTHX with internal and external conductive connections. By integrating fins penetrating the tube walls at the bottom of both annular channels, a direct metallic thermal connection node is established, enabling rapid thermal equilibrium between the inner and outer HTFs. Numerical simulation results show that at an inner-to-outer ratio of 0.7, the melting time is reduced by 35.2%; at a ratio of 0.5, the solidification time is 58.9% shorter than that of the novel TTHX at the same ratio and 41.8% shorter than its optimal solidification time. The performance enhancement is attributed to multi-path heat transfer and the full development of two independent natural convection zones. This study achieves a shift from quantitative enhancement to targeted point-specific enhancement, providing new insights for the design of efficient latent heat storage systems.

References

[1] L. Vallese, H. Javadi, B. Badenes, J. F. Urchueguia, G. Lombardo, D. Menegazzo, et al., A comprehensive review of thermal energy storage technologies and their applications: Creation of a database, Renew Sust Energ Rev 225 (2026) 116133. https://doi.org/10.1016/j.rser.2025.116133.

[2] H. Togun, H. S. Sultan, H. I. Mohammed, A. M. Sadeq, N. Biswas, H. A. Hasan, et al., A critical review on phase change materials (PCM) based heat exchanger: Different hybrid techniques for the enhancement, J Energy Storage 79 (2024) 109840. https://doi.org/10.1016/j.est.2023.109840.

[3] Z. Chang, K. Wang, X. Wu, G. Lei, Q. Wang, H. Liu, et al., Review on the preparation and performance of paraffin-based phase change microcapsules for heat storage, J Energy Storage 46 (2022) 103840. https://doi.org/10. 1016/j. est.2021.103840.

[4] M. Wang, W. Liu, J. Wang, J. Xu, Research progress of shell-and-tube heat exchanger of latent heat storage (in Chinese), J Eng Therm Energy Power 38 (2023) 1 – 12. https://doi.org/10.16146/j.cnki.rndlgc.2023.10.001.

[5] B. Kurşun, M. Balta, K. Karabulut, Exploring the impact of inner and middle channel geometries on the melting rate of PCM-metal foam composition in a triplex tube heat exchanger, Therm Sci Eng Prog 51 (2024) 102621. Https://doi.org/10.1016/j.tsep.2024. 102621.

[6] B. Basal, A. Ünal, Numerical evaluation of a triple concentric-tube latent heat thermal energy storage. Sol Energy, 92 (2013) 196 –205. https://doi.org/10.1016/j.solener.2013.02.032.

[7] R. Eibahjaoui, H. E. Qarnia, A. Naimi, Thermal performances analysis of combined solar collector with triple concentric-tube latent heat storage systems, Energ Buildings 168 (2018) 438 – 456. https://doi.org/ 10.1016/j. enbuild. 2018.02.055.

[8] G. Chen, G. Sun, D. Jiang, Y. Su, Experimental and numerical investigation of the latent heat thermal storage unit with PCM packing at the inner side of a tube, Int J Heat and Mass Tran 152 (2020) 119480. https://doi. org/ 10. 1016/j.ijheatmasstransfer.2020.119480.

[9] K. Y. Leong, S. Hasbi, B. A. Gurunatha, State of art review on the solidification and melting characteristics of phase change material in triplex-tube thermal energy storage, J Energy Storage 41 (2021) 102932. https://doi. org/10. 1016/ j.est. 2021.102932.

[10] M. Gorzin, M. J. Hosseinib, A. A. Ranjbar, R. Bahrampoury, Investigation of PCM charging for the energy saving of domestic hot water system, Appl Therm Eng 137 (2018) 659 – 668. https://doi.org/ 10.1016/j. applthermaleng. 2018.04.016.

[11] M. Sriram, A. Bhattacharya, Analysis and optimization of triple tube phase change material based energy storage system, J Energy Storage 36 (2021) 102350. https://doi.org/10.1016/j.est.2021.102350.

[12] B. Hussain, M. Irfan, M. M. Khan, S. Ullah, F. Hasnain, Geometric optimization of fin structures for accelerated melting of phase change material in a triplex tube heat exchanger, J Energy Storage 79 (2024) 110162. https://doi.org/10.1016/j.est.2023.110162.

[13] M. M. Zaytoun, M. M. El-Bashouty, M. M. Sorour, M. A. Alnakeeb, Heat transfer characteristics of PCM inside a modified design of shell and tube latent heat thermal energy storage unit, Case stud therm Eng 49 (2023) 103372. https://doi.org/10.1016/j.csite. 2023.103372.

[14] S. Seddegh, X. Wang, A. D. Henderson, A comparative study of thermal behavior of a horizontal and vertical shell-and-tube energy storage using phase change materials, Appl Therm Eng 93 (2016) 348 – 358. https://doi.org/ 10. 1016/j. applthermaleng.2015.09.107.

[15] M. Wang, X. Dou, W. Liu, K. Fu, Enhanced thermal performance of a multi-module latent heat storage heat exchanger with mesh-like flow channels, Energy 334 (2025) 137857. https://doi.org/10.1016/j.energy.2025.137857.

[16] M. Mozafari, A. Lee, S. Cheng, A novel dual-PCM configuration to improve simultaneous energy storage and recovery in a triplex-tube heat exchanger, Int J Heat Mass Transf 186 (2022) 122420. https://doi.org/ 10. 1016/ j. ijheatmasstransfer.2021.122420.

[17] M. Wang, W. Liu, Thermal performance analysis of a new multiple flat-plate latent heat storage heat exchanger, J Energy Storage 98 (2024) 113035. https://doi.org/10.1016/j.est.2024.113035.