Melting performance enhancement of phase change material by a limited amount of metal foam: Configurational optimization and economic assessment

Yang, Xu; Li, Ming-Jia; Zheng, Zhang‐Jing; Xue, Xiaodai

doi:10.1016/j.apenergy.2017.12.082

Cited by 168 publications

(38 citation statements)

References 56 publications

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“…For natural convection problems, Grashof number or more comprehensively Rayleigh number is used indicating the ratio of natural convection to conduction heat transfer and for a uniform wall heating flux is defined as 61 …”

Section: Resultsmentioning

confidence: 99%

“…The mentioned dimensionless parameters are employed in different studies in the literature for defining the variation of liquid fraction. 42,60–64 To find the variation of liquid fraction with the mentioned dimensionless parameters, since the problem is transient, the effect of Fourier number is studied. Based on the literature and due to the fact that the liquid fraction is directly a function of time, it is proposed that the liquid fraction is varied with the Fourier number directly.…”

Section: Resultsmentioning

confidence: 99%

“…As shown, a higher liquid fraction is achieved by reducing the Stefan number at a constant Fourier number, or a constant liquid fraction is achieved at a higher Fourier number for a lower Stefan number which is also reported in the literature. 61 The reason can be explained based on equation (24). For constant properties of PCM and a constant height, Stefan number decreases by increasing qw, and therefore, at a same time or for equal furious numbers, a higher liquid fraction is achieved.…”

Section: Resultsmentioning

confidence: 99%

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Numerical modelling of phase change material melting process embedded in porous media: Effect of heat storage size

Talebizadehsardari

Walker

Gillott

et al. 2019

Proceedings of the Institution of Mechanical Engineers, Part A:

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The aim of this paper is to study the influence of enclosure size in latent heat thermal energy storage systems embedded in a porous medium for domestic usage of latent heat thermal energy storage heat exchangers. A 2-D rectangular enclosure is considered as the computational domain to study the heat transfer improvement for a phase change material embedded in a copper foam considering a constant heat flux from the bottom surface. Different dimensions of the composite system are examined compared with a system without a porous medium. The thermal non-equilibrium model with enthalpy-porosity method is employed for the effects of porous medium and phase change in the governing equations, respectively. The phase change material liquid fraction, temperature, velocity, stream lines and the rate of heat transfer are studied. The presence of a porous medium increases the heat transfer significantly, but the improvement in melting performance is strongly related to the system's dimensions. For the dimensions of 200 × 100 mm (W × H), the melting time of porous-phase change material with the porosity of 95% is reduced by 17% compared with phase change material-only system. For the same storage volume and total amount of thermal energy added, the melting time is lower for the system with a lower height, especially for the phase change material-only system due to a higher area of the input heat. The non-dimensional analysis results in curve-fitting correlations between the liquid fraction and Fo.Ste.Ra −0.02 for rectangular latent heat thermal energy storage systems for both phase change material-only and composite-phase change material systems within the parameter range of 1.16 < Ste < 37.13, 0 < Fo < 1.5, 2.9 × 104 < Ra < 9.5 × 108, 0 < L f < 1 and 0 < Fo.Ste.Ra −0.02 < 0.57. Over a range of system's volume, heat flux and surface area of the input heat flux, the benefit of composite phase change material is variable and, in some cases, is negligible compared with the phase change material-only system.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Numerical modelling of phase change material melting process embedded in porous media: Effect of heat storage size

Talebizadehsardari

Walker

Gillott

et al. 2019

Proceedings of the Institution of Mechanical Engineers, Part A:

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show abstract

“…There is between 5 and 20 times improvement of thermal behavior in the solid-state and overall 3 to 10 times higher heat transfer in all zones over the alone-PCM case. Xu et al 37,38 analyzed a horizontal double-pipe LHSHX partially loaded with a metal foam and optimized the location of the foam inserted in the domain. An economic analysis developed a correlation for the melting fraction and noticed that the presence of partially filled porous medium at the bottom part has a similar impact in comparison with the state of fully filled porous medium.…”

Section: Introductionmentioning

confidence: 99%

Effect of airflow channel arrangement on the discharge of a composite metal foam‐phase change material heat exchanger

et al. 2020

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Summary The effect of various arrangements of airflow channel in a proposed storage heater based on copper foam soaked in a phase change material (PCM) is investigated. Different configurations of the air channel using a serpentine channel, as well as numbers of the air channels, are examined in a representative three‐dimensional computer‐based model (Ansys Fluent). Evaluation is performed by PCM discharging rate and output air temperature of the unit. The goal is to improve both uniformity and value of air temperature. Changing the airflow arrangement using serpentine configuration to increase heat exchange surface area reduces solidification time and increases output maximum air temperature as well as pressure drop; conversely, exit air achieves lower temperature uniformity. In the case of the shortest solidification time using one air‐channel with the length of 51 cm, the solidification time reduces to almost 6 hours, compared with 13.6 hours for the straight channel with 37 cm length, with the average output temperature of 56°C compared to 41°C for the straight channel; however, the achieved temperature difference from the initial to the end of solidification time is 13.7°C compared to 4.5°C for the straight tube.

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“…Nonetheless, knowing the fact that the PCMs have low thermal conductivity by instinct, which extremely affects the thermal performance in thermal energy systems, many investigators have tried to increase the overall thermal performance of the systems implementing several methods, such as using porous metal foams [3,4,5,6], metal matrix [7], fin [8,9,10,11], and nanoparticles dispersed into the PCMs [12,13,14,15], and nano-encapsulation PCMs [16,17,18,19]. Since nanoparticles play a promising role in enhancing the thermal performance of multifarious systems, the mixture of PCM and nanoparticles to produce Nano-enhanced Phase Change Materials (NePCM) has been extensively investigated.…”

Section: Introductionmentioning

confidence: 99%

Free convection of a suspension containing nano-encapsulated phase change material in a porous cavity; local thermal non-equilibrium model

Ghalambaz

Zadeh

Mehryan

et al. 2020

Heliyon

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Due to the instinctive temperature-dependent heat capacity of the Nano-Encapsulated Phase Change Material (NEPCM), there is a growing interest in the potential applications of such materials in heat transfer. As such, steady-state natural convection in a porous enclosure saturated with nanofluid using NEPCMs has been investigated in this study. The cavity is assumed to have constant hot and cold temperatures at the left and right vertical boundaries, respectively, and fully insulated from the bottom and top walls. Considering the Local Thermal Nonequilibrium (LTNE) approach for the porous structure, the governing equations are first non-dimensionalized and then solved by employing the finite element Galerkin method. The impact of different parameters, such as porous thermal conductivity (k s ), solid-fluid interface heat transfer (10 H 10 5 ), Stefan number (0.2 Ste 1), and volume fraction of nanoparticles (0.0 φ 0.05) on the patterns of the fluid and solid isotherms, streamlines and the contours of the heat capacity ratio, fusion temperature (0.05 θ f 1), local and average Nusselt numbers, and overall heat transfer ratio has been studied. It is shown that improving the porous thermal conductivity not only leads to an increase in the rate of heat transfer but also augments the fluid flow inside the cavity. For low values of the Ste, the rate of heat, transferred in the porous enclosure, is intensified. However, regardless of the amount of the Stefan number, the maximum rate of heat transfer is achievable when the non-dimensional fusion temperature is approximately 0.5. Employing NEPCMs in a highly conductive porous structure is more efficacious only when the phases are in the state of local thermal equilibrium. Nonetheless, the rate of heat transfer is higher when the Local thermal non-equilibrium is validated between the phases. Besides, for poor thermal conductivity of the porous medium like glass balls (LTE condition), adding 5% of the nano-encapsulated phase change materials to pure water can boost the rate of heat transfer up to 47% (for Ste ¼ 0.2 and θ f ¼ 0.5). This thermal investigation of NEPCMs shows in detail how advantageous are these nanoparticles in heat transfer and opens up an avenue for further application-based studies.

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Melting performance enhancement of phase change material by a limited amount of metal foam: Configurational optimization and economic assessment

Cited by 168 publications

References 56 publications

Numerical modelling of phase change material melting process embedded in porous media: Effect of heat storage size

Numerical modelling of phase change material melting process embedded in porous media: Effect of heat storage size

Effect of airflow channel arrangement on the discharge of a composite metal foam‐phase change material heat exchanger

Free convection of a suspension containing nano-encapsulated phase change material in a porous cavity; local thermal non-equilibrium model

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