NUMERICAL STUDY OF THE ERYTHRITOL MELTING PROCESS IN A TRIDIMENSIONAL RECTANGULAR CAVITY

2015 ◽  
Vol 14 (1) ◽  
pp. 88
Author(s):  
J. F. Raymundo ◽  
R. Da S. Borahel ◽  
R. De C. Oliveski
Keyword(s):  
Energy Storage ◽  
Phase Change ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Volume Fraction ◽  
Numerical Study ◽  
Practical Interest ◽  
Melting Process ◽  
Rectangular Cavity ◽  
Computational Domain

Many areas of engineering, such as the petrochemical and food industries, use thermal energy storage to achieve better performance. Thermal energy storage can be used as a heat source or a heat sink. The thermal storage/release technology, based on the use of phase change materials (PCMs), which possess a great capacity of heat accumulation, has raised an important practical interest. Indeed, the improved storage density and the constant temperature release of energy allow a more compact heat exchange design and simplify system management. Phase change phenomena occurring during PCM melting and PCM solidification need to be carefully controlled. The aim of the present numerical study is to investigate the heat transfer and hydrodynamic characteristics of a phase change material (PCM) in a rectangular cavity and the melting process dependence on the cavity height. The geometry consists of a mini rectangular cavity which contains PCM. Water or steam flows in the longitudinal direction of the cavity, thus heating or cooling the PCM in the cavity. The computational domain is made of three materials: air, aluminum and PCM. The grid mesh is structured, hexaedrical and refined near the walls. The study is developed with different operation conditions of the mass flow and water temperature. The numerical simulation is developed through CFD (Computational Fluid Dynamics) with the Fluent code. The mathematical model was validated using results available in the literature. Results of temperature, velocity and volume fraction fields indicate that the cavity height has no impact on the melting process.

scholarly journals Phase-Transition Thermal Charging of a Channel-Shape Thermal Energy Storage Unit: Taguchi Optimization Approach and Copper Foam Inserts

Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1235
Author(s):  
Mohammad Ghalambaz ◽  
Seyed Abdollah Mansouri Mehryan ◽  
Ahmad Hajjar ◽  
Obai Younis ◽  
Mikhail A. Sheremet ◽  
...  
Keyword(s):  
Energy Storage ◽  
Phase Change ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Metal Foam ◽  
Volume Fraction ◽  
Foam Layer ◽  
Storage Unit ◽  
Energy Storage Unit ◽  
Copper Foam

Thermal energy storage is a technique that has the potential to contribute to future energy grids to reduce fluctuations in supply from renewable energy sources. The principle of energy storage is to drive an endothermic phase change when excess energy is available and to allow the phase change to reverse and release heat when energy demand exceeds supply. Unwanted charge leakage and low heat transfer rates can limit the effectiveness of the units, but both of these problems can be mitigated by incorporating a metal foam into the design of the storage unit. This study demonstrates the benefits of adding copper foam into a thermal energy storage unit based on capric acid enhanced by copper nanoparticles. The volume fraction of nanoparticles and the location and porosity of the foam were optimized using the Taguchi approach to minimize the charge leakage expected from simulations. Placing the foam layer at the bottom of the unit with the maximum possible height and minimum porosity led to the lowest charge time. The optimum concentration of nanoparticles was found to be 4 vol.%, while the maximu possible concentration was 6 vol.%. The use of an optimized design of the enclosure and the optimum fraction of nanoparticles led to a predicted charging time for the unit that was approximately 58% shorter than that of the worst design. A sensitivity analysis shows that the height of the foam layer and its porosity are the dominant variables, and the location of the porous layer and volume fraction of nanoparticles are of secondary importance. Therefore, a well-designed location and size of a metal foam layer could be used to improve the charging speed of thermal energy storage units significantly. In such designs, the porosity and the placement-location of the foam should be considered more strongly than other factors.

Effect of Fin Orientation on Melting Process in Horizontal Double Pipe Thermal Energy Storage Systems

2021 ◽  
pp. 1-16
Author(s):  
Nesrine Boulaktout ◽  
El-Hacène Mezaache ◽  
Mohamed Teggar ◽  
Müslüm Arici ◽  
K.A.R. Ismail ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Energy Storage ◽  
Phase Change ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Storage Systems ◽  
Melting Process ◽  
Storage Unit ◽  
Charging Time ◽  
Thermal Energy Storage Systems

Abstract Immersion of fins in latent heat thermal energy storage systems has been used as an influential approach to remedy the poor thermal conductivity of phase-change materials. Present paper numerically investigates heat transfer and phase change improvement by means of longitudinal fins in a shell and tube thermal energy storage unit. The main aim of this study is to investigate the effect of fin orientation on the performance of the storage unit. Six configurations of different fin numbers (2, 4 and 8 fins) and orientations (π/2, π/4, and π/8) are tested. For simulations, a 2D mathematical model incorporating the enthalpy-porosity method and finite volume techniques are established and solved by ANSYS-Fluent. The numerical predictions are successfully validated by comparison with experimental and numerical data from the literature. Heat transfer characteristics and melting process are analyzed through streamlines, isotherms, mean temperature, heat flux and heat transfer coefficient as well as transient melting front position and liquid fractions. Results show that orientation of fins has significant impact on the charging time for two cases (2 and 4 fins) whereas no significant reduction in charging time was obtained for the case of 8 fins. In case of utilizing 2 fins, a fin orientation of 0° (vertical fins) shortens the charging time by up to 2.5 folds compared to the horizontal fins (90°). These results could help designing efficient latent thermal energy storage units.

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