Simulation Study of Solidification in the Shell-And-Tube Energy Storage System with a Novel Dual-PCM Configuration

Moslem Mozafari,Shaokoon Cheng,Ann Lee

doi:10.3390/en15030832

Abstract

This study proposes a novel dual-PCM configuration with outstanding solidification response in a horizontal shell-and-tube energy storage system. To demonstrate that the proposed PCM configuration is superior in its thermal responses, results from a range of numerical simulations are presented and compared between different configurations of dual-PCM. As the melting/solidus point is a crucial factor for the solidification rate, dual PCMs are chosen such that the average of their melting point is equal to the melting point of the single-PCM in the reference case. Additionally, equal-area sectors are considered for all cases to ensure the same quantities of PCMs are compared. The temporal liquid fraction and temperature contours reveal that solidification is delayed in the upper half of the system due to strong natural convection motions. Therefore, a dual-PCM configuration is offered to improve the solidification rate in this region and accelerate the full solidification process. Results show that placing a PCM with a lower solidus point in the lower half or an annulus-shaped zone around the cold tube can save the full recovery time up to 8.51% and 9.36%, respectively. The integration of these two strategies results in a novel and optimum design that saves the solidification time up to 15.09%.

Highlights

There is a growing environmental concern regarding the increasing usage of fossil fuels, and solar energy has gained much attention as an important substitute [1]
The heat recovery was studied in the solidification of Phase change materials (PCMs) in a shell-and-tube storage system
Different configurations of dual-PCM were comparatively investigated against a single-PCM configuration

Summary

Introduction

There is a growing environmental concern regarding the increasing usage of fossil fuels, and solar energy has gained much attention as an important substitute [1]. Thermal energy storage (TES) systems have been introduced as an attractive way to store solar energy [2,3]. Phase change materials (PCMs) are highly used in latent thermal energy storage (LTES) systems due to their high latent energy capacity [3,4,5]. A TES system with PCM can store 5–14 times more energy than a system using suitable storage materials of the same volume [6]. The usage of PCMs has received widespread interest, with clear evidence demonstrating the important roles they have in the storage and recovery of solar energy [7,8], energy savings in buildings [9,10,11], and electronics cooling [12,13]

Objectives

Methods

Results

Conclusion