Melting phase change heat transfer in a quasi-petal tube thermal energy storage unit.

S A M Mehryan,Pouyan Talebizadeh Sardari,Sayed Reza Ramezani,Mohammad Ghalambaz,Ahmad Hajjar,Kaamran Raahemifar,Obai Younis,Djamel Eddine Ameziani

doi:10.1371/journal.pone.0246972

Abstract

In the present study, the thermal energy storage of a hot petal tube inside a shell-tube type Thermal Energy Storage (TES) unit was addressed. The shell is filled with the capric acid Phase Change Material (PCM) and absorbs the heat from a hot U-tube petal. The governing equations for the natural convection flow of molten PCM and phase change heat transfer were introduced by using the enthalpy-porosity approach. An automatic adaptive mesh scheme was used to track the melting interface. The accuracy and convergence of numerical computations were also controlled by a free step Backward Differentiation Formula. The modeling results were compared with previous experimental data. It was found that the present adaptive mesh approach can adequately the melting heat transfer, and an excellent agreement was found with available literature. The effect of geometrical designs of the petal tube was investigated on the melting response of the thermal energy storage unit. The phase change behavior was analyzed by using temperature distribution contours. The results showed that petal tubes could notably increase the melting rate in the TES unit compared to a typical circular tube. Besides, the more the petal numbers, the better the heat transfer. Using a petal tube could increase the charging power by 44% compared to a circular tube. The placement angle of the tubes is another important design factor which should be selected carefully. For instance, vertical placement of tubes could improve the charging power by 300% compared to a case with the tubes’ horizontal placement.

Highlights

The energy demand has been increased significantly in recent decades due to the dramatic increase in the population in addition to technological and industrial developments
It should be noted that the fusion temperature of the Phase Change Material (PCM) is Tm = 305 k, which means that PCM in the zones where the temperature is higher than Tm is melted and in the liquid state, while in the other zones, it remains in the solid-state
The heated zone increases in size, and as the PCM melts, it undergoes free convection as the hot melt moves upwards

Summary

Introduction

The energy demand has been increased significantly in recent decades due to the dramatic increase in the population in addition to technological and industrial developments. These advancements have posed a challenge to clean energy production with a justified economic value and not harmful to the environment. In the last two decades, they have been used in engineering applications extensively These applications include- but are not limited to- heat and tube heat exchangers [1,2,3,4], Thermal energy storage systems [5,6,7,8,9,10,11], and electronic devices cooling [12,13,14,15,16,17]

Methods

Results

Conclusion