Analysis of HTFs, PCMs and fins effects on the thermal performance of shell–tube thermal energy storage units

Li, Zhuo; Wu, Zhiming

doi:10.1016/j.solener.2015.09.019

Cited by 98 publications

(29 citation statements)

References 39 publications

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“…For the PCM, the enthalpy-porosity method [34][35][36][37][38][39] was applied to model the dynamic melting process, modelling equations including the continuity, momentum, and energy equations are shown below:…”

Section: Numerical Modellingmentioning

confidence: 99%

“…Compared to the experimental and analytical approaches, numerical simulations are more effective in dealing with influential factors, such as natural convection [33][34][35][36][37][38][39], geometric configuration [33][34][35][36], dynamic melting process [37] and non-dimensional number [38], etc. Fan et al [33] studied a constrained melting process in a circumferentially finned spherical capsule, the influence of fin height on the TES performance was In general, TES systems can be divided into two types: sensible heat thermal energy storage (SHTES) systems and latent heat thermal energy storage (LHTES) systems [21].…”

Section: Introductionmentioning

confidence: 99%

“…Fan et al [33] studied a constrained melting process in a circumferentially finned spherical capsule, the influence of fin height on the TES performance was revealed. Li and Wu [34] analyzed the TES performance with multiple geometric configurations and PCMs. Their results showed that the melting and solidification time of a TES unit with fins can be shortened by at least 14%.…”

Section: Introductionmentioning

confidence: 99%

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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%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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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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“…The shape and position of the fin is crucial to achieve good heat transference. Most of the studies are focused on simple geometries, being longitudinal straight fins [19,20,21] and circular fins [22] the most studied geometries. Some studies had shown a better performance from longitudinal fins [23] rather than circular.…”

Section: Thermal Conductivity Enhancement Systemsmentioning

confidence: 99%

Performance comparison of a group of thermal conductivity enhancement methodology in phase change material for thermal storage application

et al. 2016

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a b s t r a c tPhase change materials (PCM) are able to store thermal energy when becoming liquids and to release it when freezing. Recently the use of PCM materials for thermal energy storage (TES) at high temperature for Concentrated Solar Power (CSP) technology has been widely studied. One of the main investigated problems is the improvement of their low thermal conductivity. This paper looks at the current state of research in the particular field of thermal conductivity enhancement (TCE) mechanisms of PCM to be used as TES. This work considers a numerical approach to evaluate the performance of a group of TCE solutions composed by particular configurations of two of the principal TCE systems found on the literature: finned pipes and conductive foams. The cases are compared against a single PCM case, used as reference. Three different grades of graphite foams have been studied, presenting a charge time 100 times lower than the reference case for the same capacity. For fins two materials are analyzed: carbon steel and aluminum. The charge times of fin cases are from 3 to 15 times faster, depending on the amount and type of material employed. The internal mechanisms are analyzed to understand the results and locate possible improvement.

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“…The heat transfer medium is responsible for transmitting the collected solar energy to the power generation system in the concentrating solar power system, which is stored in each heat‐absorbing unit, so the heat transfer medium directly affects the efficiency of the whole system (Fornarelli, Camporeale, & Fortunato, ; Khalifa, Tan, Date, & Akbarzadeh, ). Because the Sun's daily cycle of movement and weather conditions are constantly changing, it is not sustainable to provide solar energy (Li & Wu, ; Liu, Saman, & Bruno, ); it must be absorbed as solar radiation and stored in the heat storage system; in case the sun is too light or too weak to use, this can improve the efficiency of the use of the concentrated solar system (Longeon, Soupart, & Fourmigué, ; Moe, Dominic, & Alain, ).…”

Section: Introductionmentioning

confidence: 99%

Experimental study on optimization of heat storage and melting salts of solar energy

Ullah

Ameen

Hasrat

2018

J Food Process Preserv

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In this research work, we have conducted an experiment on the requirements of high temperature in solar thermal and thermal energy of solar concentrating. The mixed salts of (NaCl) Sodium Chloride, (MgCl2) Magnesium Chloride, and (KCl) Potassium Chloride with a wide range of use and stable properties were selected in the solar heat‐transfer thermal storage system. Thirty‐six kinds of mixed chlorinated molten salts with different weight ratios were configured, using differential scanning calorimetric (DSC). The melting point of different proportions of molten salts was determined, and the results showed that the melting point of 36 kinds of mixed salts was concentrated which was distributed in the range of 400℃ and 465℃. On this basis, the specific heat of 11 different proportions of molten salts in the melting point near 400℃ was determined. The thermal storage cost was analyzed and the results show that the quality ratio of 2:7:1 for MgCl2, NaCl, and KCl, respectively, and the lowest heat storage cost was the best heat storage medium. At last, the equation of the specific heat and temperature of the mixed salts in the molten state was obtained using the least square method. Practical applications In this research paper, we have discussed and optimized heat storage and melting salts of solar energy with mixed salts of (NaCl) Sodium Chloride, (MgCl2) Magnesium Chloride, and (KCl) Potassium Chloride with a wide range of use and stable properties were selected in the solar heat‐transfer thermal storage system. Thirty‐six kinds of mixed chlorinated molten salts with different weight ratios were configured, using differential scanning calorimetric (DSC). According to the experiment, the research work is beneficial for the development of remote, arid, and rural areas.

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Analysis of HTFs, PCMs and fins effects on the thermal performance of shell–tube thermal energy storage units

Cited by 98 publications

References 39 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

Performance comparison of a group of thermal conductivity enhancement methodology in phase change material for thermal storage application

Experimental study on optimization of heat storage and melting salts of solar energy

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