Impact of Tube Bundle Placement on the Thermal Charging of a Latent Heat Storage Unit

Mohammad Ghalambaz,Amir Hossein Eisapour,Mohammad S Islam,Pouyan Talebizadeh Sardari,Wahiba Yaïci,Obai Younis,Hayder I Mohammed

doi:10.3390/en14051289

Abstract

The melting process of a multi-tube’s thermal energy storage system in the existence of free convection effects is a non-linear and important problem. The placement of heated tubes could change the convective thermal circulation. In the present study, the impact of the position of seven heat exchanger tubes was systematically investigated. The energy charging process was numerically studied utilizing liquid fraction and stored energy with exhaustive temperature outlines. The tubes of heat transfer fluid were presumed in the unit with different locations. The unit’s heat transfer behavior was assessed by studying the liquid fraction graphs, streamlines, and isotherm contours. Each of the design factors was divided into four levels. To better investigate the design space for the accounted five variables and four levels, an L16 orthogonal table was considered. Changing the location of tubes could change the melting rate by 28%. The best melting rate was 94% after four hours of charging. It was found that the tubes with close distance could overheat each other and reduce the total heat transfer. The study of isotherms and streamlines showed the general circulation of natural convection flows at the final stage of melting was the most crucial factor in the melting of top regions of the unit and reduces the charging time. Thus, particular attention to the tubes’ placement should be made so that the phase change material could be quickly melted at both ends of a unit.

Highlights

The effective methods to correct the irregular global energy consumption are the major point to increase the save and production of power, which fill the gap between the power generation and the demands
We examined the melting interface for melting phase change materials (PCMs) in a rectangular enclosure with a height of 6.35 and widths of 8.89 cm
A geometrical design of an latent heat thermal energy storage (LHTES) unit heated by HTF tubes was systematically investigated

Summary

Introduction

The effective methods to correct the irregular global energy consumption are the major point to increase the save and production of power, which fill the gap between the power generation and the demands. The latent form using the phase change materials (PCMs) is the best conductive type due to the great storage capacity and isothermal behavior. A TES based on PCMs could hold 5–14-fold of latent heat compared to a unit with the same size but based on sensible heat storage materials [2]. Many researches have aimed to enhance the conductive heat transfer, which can be categorized into two groups: Improving the conductivity of the PCM and changing the latent heat system (LHS) unit structure [4]. The addition of metal foams or using fins add weight and cost to the design This is while the container’s geometrical modification could be more desirable since it could add minimal weight or cost to a TES unit

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Conclusion