Numerical investigation of heat transfer mechanism in a vertical shell and tube latent heat energy storage system

Seddegh, Saeid; Wang, Xiaolin; Henderson, AD

doi:10.1016/j.applthermaleng.2015.05.067

Cited by 135 publications

(27 citation statements)

References 29 publications

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“…where A mush is the mushy zone constant and varies between 10 4 and 10 7 , according to previous literatures, 10 5 is applied [43][44][45][46]. The constant χ is a small number to prevent division by zero.…”

Section: Numerical Modellingmentioning

confidence: 99%

Investigation of the Dynamic Melting Process in a Thermal Energy Storage Unit Using a Helical Coil Heat Exchanger

et al. 2017

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Abstract:In this study, the dynamic melting process of the phase change material (PCM) in a vertical cylindrical tube-in-tank thermal energy storage (TES) unit was investigated through numerical simulations and experimental measurements. To ensure good heat exchange performance, a concentric helical coil was inserted into the TES unit to pipe the heat transfer fluid (HTF). A numerical model using the computational fluid dynamics (CFD) approach was developed based on the enthalpy-porosity method to simulate the unsteady melting process including temperature and liquid fraction variations. Temperature measurements using evenly spaced thermocouples were conducted, and the temperature variation at three locations inside the TES unit was recorded. The effects of the HTF inlet parameters were investigated by parametric studies with different temperatures and flow rate values. Reasonably good agreement was achieved between the numerical prediction and the temperature measurement, which confirmed the numerical simulation accuracy. The numerical results showed the significance of buoyancy effect for the dynamic melting process. The system TES performance was very sensitive to the HTF inlet temperature. By contrast, no apparent influences can be found when changing the HTF flow rates. This study provides a comprehensive solution to investigate the heat exchange process of the TES system using PCM.

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Section: Numerical Modellingmentioning

confidence: 99%

Investigation of the Dynamic Melting Process in a Thermal Energy Storage Unit Using a Helical Coil Heat Exchanger

et al. 2017

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“…For validation, a comparison of these models to an ANSYS Fluent [29] model was undertaken. Since conduction is the dominant heat transfer type during discharge [7,24], convectional effects in the liquid PCM were neglected for reasons of model simplification.…”

Section: Introductionmentioning

confidence: 99%

“…In order to extend the range of application and to achieve better storage performances, research activities have been carried out to examine the heat transfer process [4,7,8]; storage types and configurations like a combination of different PCMs within one storage unit [9][10][11][12][13][14][15]; and the integration of highly heat conductive materials into the storage material, examples of which are copper, aluminum, stainless steel or carbon fiber [16][17][18][19][20][21][22]. These materials can be integrated in different forms, such as fins, honeycombs, wool or brush-form.…”

Section: Introductionmentioning

confidence: 99%

Numerical Analysis of Shell-and-Tube Type Latent Thermal Energy Storage Performance with Different Arrangements of Circular Fins

2017

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Latent thermal energy storage (LTS) systems are versatile due to their high-energy storage density within a small temperature range. In shell-and-tube type storage systems fins can be used in order to achieve enhanced charging and discharging power. Typically, circular fins are evenly distributed over the length of the heat exchanger pipe. However, it is yet to be proven that this allocation is the most suitable for every kind of system and application. Consequently, within this paper, a simulation model was developed in order to examine the effect of different fin distributions on the performance of shell-and-tube type latent thermal storage units at discharge. The model was set up in MATLAB Simulink R2015b (The MathWorks, Inc., Natick, MA, USA) based on the enthalpy method and validated by a reference model designed in ANSYS Fluent 15.0 (ANSYS, Inc., Canonsburg, PA, USA). The fin density of the heat exchanger pipe was increased towards the pipe outlet. This concentration of fins was implemented linearly, exponentially or suddenly with the total number of fins remaining constant during the variation of fin allocations. Results show that there is an influence of fin allocation on storage performance. However, the average storage performance at total discharge only increased by three percent with the best allocation compared to an equidistant arrangement.

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“…The transition from a conductive to a convective regime produced a significant increase in thermal exchange with a reduction in charging and discharging times and consequent increase in available thermal power and system efficiency. The conditions necessary to establish these convective motions have been extensively studied both experimentally [30,[34][35][36] and numerically [37][38][39][40][41]. The last goal is to promote this sort of heat exchange within the LHTES to achieve an optimized and efficient system.…”

Section: Advancements In Energy Storage Technologiesmentioning

confidence: 99%

Heat Exchange Analysis on Latent Heat Thermal Energy Storage Systems Using Molten Salts and Nanoparticles as Phase Change Materials

Miliozzi¹,

Liberatore²,

Nicolini³

et al. 2018

Advancements in Energy Storage Technologies

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The increase of carbon dioxide emissions is the most important contributor to climate change. A better use of produced energy, increasing systems efficiency and using renewable sources, can limit them. A key technological issue is to integrate a thermal energy storage (TES). It consists in stocking thermal energy through the heating/cooling of a storage material for future needs. Among various technologies, latent heat TES (LHTES) provides high energy storage density at constant temperature during melting/solidification of storage media. The bottleneck in the use of typical PCMs is their low thermal conductivity. To improve the heat exchange between heat transfer fluid and PCM, three methods are possible and here experimentally analyzed: conductivity systems enhancements; convective flows promotion in liquid phase; and improvement of PCM thermal properties including small amounts of nanoparticles. CFD models were used to evaluate physical phenomena that are crucial for optimized LHTES systems design. The study of the heat exchange mode allowed some useful indications to achieve an optimized LHTES, taking advantage by convective flows and conductivity promotion systems. The use of NEPCM, to maximize the stored energy density and realize compact systems, makes necessary the improvement of its thermal diffusivity. These will be the future research topics.

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Numerical investigation of heat transfer mechanism in a vertical shell and tube latent heat energy storage system

Cited by 135 publications

References 29 publications

Investigation of the Dynamic Melting Process in a Thermal Energy Storage Unit Using a Helical Coil Heat Exchanger

Investigation of the Dynamic Melting Process in a Thermal Energy Storage Unit Using a Helical Coil Heat Exchanger

Numerical Analysis of Shell-and-Tube Type Latent Thermal Energy Storage Performance with Different Arrangements of Circular Fins

Heat Exchange Analysis on Latent Heat Thermal Energy Storage Systems Using Molten Salts and Nanoparticles as Phase Change Materials

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