Evaluation of Melting Mechanism and Natural Convection Effect in a Triplex Tube Heat Storage System with a Novel Fin Arrangement

Abstract

In this research, a numerical analysis is accomplished aiming to investigate the effects of adding a new design fins arrangement to a vertical triplex tube latent heat storage system during the melting mechanism and evaluate the natural convection effect using Ansys Fluent software. In the triplex tube, phase change material (PCM) is included in the middle tube, while the heat transfer fluid (HTF) flows through the interior and exterior pipes. The proposed fins are triangular fins attached to the pipe inside the PCM domain in two different ways: (1) the base of the triangular fins is connected to the pipe, (2) the tip of the triangular fins is attached to the pipe and the base part is directed to the PCM domain. The height of the fins is calculated to have a volume equal to that of the uniform rectangular fins. Three different cases are considered as the final evaluation toward the best case as follows: (1) the uniform fin case (case 3), (2) the reverse triangular fin case with a constant base (case 12), (3) the reverse triangular fin case with a constant height (case 13). The numerical results show that the total melting times for cases 3 and 12 increase by 4.0 and 10.1%, respectively, compared with that for case 13. Since the PCM at the bottom of the heat storage unit melts slower due to the natural convection effect, a flat fin is added to the bottom of the heat storage unit for the best case compared with the uniform fin cases. Furthermore, the heat storage rates for cases 3 and 12 are reduced by 4.5 and 8.5%, respectively, compared with that for case 13, which is selected as the best case due to having the lowest melting time (1978s) and the highest heat storage rate (81.5 W). The general outcome of this research reveals that utilizing the tringle fins enhances the thermal performance and the phase change rate.

Numerical simulation study of the effect of mechanical vibration on heat transfer in a six-fin latent heat thermal energy storage unit

“…F.T. Najim et al [21] studied a new design fins arrangement to a vertical triplex tube latent heat storage system during the melting mechanism, the result shows that the slope of the sides of the triangular fins has a determinant role in the circulation of the PCM inside the heat storage unit. A.H. Eisapour et al [22] proposed wavy profiles with different amplitude characteristics and the twisted shape which benefits the configuration of LHTES.…”

Design and Research of Heat Storage Enhancement by Innovative Wave Fin in a Hot Water–Oil-Displacement System

“…Extensive research has been undertaken with the aim of enhancing the thermal efficiency of LHTES systems [13,14]. These studies have focused on various approaches, including the use of metal fins or metal foam [15,16], dispersing nanoparticles in PCM to improve overall heat exchange efficiency [17,18], and packaging PCM to improve heat transfer uniformity [19,20]. Among these approaches, enhancing heat transfer performance through metal fins is advantageous due to its simplicity and efficiency [21].…”

Numerical analysis of the energy-storage performance of a PCM-based triplex-tube containment system equipped with arc-shaped fins

“…The effective primary way to increase energy efficiency and sustainability is the TES strategy, which has thus far caught the researcher’s attention ( IRENA, 2020 ). The TES systems are utilized in energy conservation demands ( Hasnain, 1998 ; Najim et al, 2022a ), industry, commercial building ( Heier et al, 2015 ), solar-powered energy systems ( Fath, 1998 ; Shahsavar et al, 2020 ; Ansu et al, 2021 ), and thermal management of batteries ( Mohammadi and Mohammadi, 2014 ; Keiner et al, 2019 ). In latent heat TES, the mechanism of thermal storage in the aforementioned applications is involved with phase-change materials (PCMs), which store thermal heat during the melting process as latent heat and then gives it off during solidification ( Sardari et al, 2019 ; Zhou et al, 2022 ).…”