RECENT PROGRESS IN HEAT TRANSFER DURING MELTING AND SOLIDIFICATION PROCESSES

1992 ◽  
pp. 587-604
Author(s):  
S.T. Ro
Keyword(s):  
Heat Transfer ◽  
Recent Progress ◽  
Solidification Processes ◽  
Melting And Solidification

scholarly journals Heat transfer study of poly-c PV system integrated with phase change material under semi-arid area (Errachidia-Drâa Tafilalet)

2021 ◽  
Vol 297 ◽  
pp. 01008
Author(s):  
Ibtissam Lamaamar ◽  
Amine Tilioua ◽  
Zaineb Benzaid ◽  
Abdelouahed Ait Msaad ◽  
Moulay Ahmed Hamdi Alaoui
Keyword(s):  
Heat Transfer ◽  
Phase Change ◽  
Phase Change Material ◽  
Operating Temperature ◽  
Pv System ◽  
Pv Module ◽  
Solidification Processes ◽  
Change Material ◽  
Transfer Study ◽  
Melting And Solidification

The high operating temperature of the photovoltaic (PV) modules decreases significantly its efficiency. The integration of phase change material (PCM) is one of the feasible techniques for reducing the operating temperature of the PV module. A numerical simulation of the PV module with PCM and without PCM has been realized. The thermal behavior of the PV module was evaluated at the melting and solidification processes of PCM. The results show that the integration of RT35HC PCM with a thickness of 4 cm reduces the temperature of the PV module by 8 °C compared to the reference module. Compared the RT35 and RT35HC, we found that the latent heat has a significant effect on the PCM thermal comportment. Furthermore, it has been found that the thermal resistance of the layers plays an important role to dissipate the heat from the PV cells to the PCM layer, consequently improving the heat transfer inside the PV/PCM system.

Heat Transfer During Melting and Solidification of Metals

1988 ◽  
Vol 110 (4b) ◽  
pp. 1205-1219 ◽  
Author(s):  
R. Viskanta
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Phase Transformation ◽  
Research Attention ◽  
Transfer Processes ◽  
Model Predictions ◽  
Solidification Processes ◽  
Solid Liquid ◽  
Theoretical Considerations ◽  
Melting And Solidification

Recent advances in the understanding of melting and solidification heat transfer in metals and alloys are discussed. Since heat transfer is generally the rate-determining process, the emphasis in the paper is on fundamental heat transfer processes during solid–liquid phase transformation and comparison between mathematical-numerical model predictions with experimental data. After a brief discussion of theoretical considerations, unidirectional and multidirectional melting and solidification processes are reviewed. The important role played by buoyancy-driven fluid flow is discussed and problem areas needing research attention are identified.

Second Law Analysis of Tree-Shaped Fins for the Heat Transfer Enhancement in a PCM Thermal Storage System

2013 ◽  
Author(s):  
Adriano Sciacovelli ◽  
Elisa Guelpa ◽  
Vittorio Verda
Keyword(s):  
Heat Transfer ◽  
Energy Storage ◽  
Heat Transfer Enhancement ◽  
Solidification Rate ◽  
High Energy ◽  
Second Law ◽  
Transfer Enhancement ◽  
Energy Storage Devices ◽  
Second Law Analysis ◽  
Melting And Solidification

Latent heat thermal energy storage (LHTES) systems based on phase change materials (PCMs) are a promising option to be employed as effective energy storage devices. PCM allows one to achieve high energy storage density and almost constant temperature energy retrieval, however LHTES systems performance is limited by poor thermal conductivity of the PCMs which leads to unacceptably low melting and solidification rates. Thus, heat transfer enhancement techniques are required in order to obtain acceptable melting and solidification rates. The preliminary design of a shell-and-tube LHTES unit is investigated by means of computational fluid-dynamics (CFD). Three different fin designs are considered: a conventional radial fin, a constructal Y-shaped fin design and a non-constructal Y-shaped configuration previously investigated by the authors. The performances of each fin configuration are evaluated by means of a Second-law analysis. Moreover, local and global entropy generation rates are analyzed in order to show the main source of thermodynamic irreversibilities occurring in the system. The analysis indicates that solidification rate is significantly enhanced when Y-shaped fins are adopted in the LHTES unit, however the constructal Y-shaped geometry is not optimal since further improvements can be achieved by means of a Y-shaped fins with elongated secondary branches.

scholarly journals Performance Evaluation of a Small-Scale Latent Heat Thermal Energy Storage Unit for Heating Applications Based on a Nanocomposite Organic PCM

2019 ◽  
Vol 3 (4) ◽  
pp. 88 ◽  
Author(s):  
Maria K. Koukou ◽  
George Dogkas ◽  
Michail Gr. Vrachopoulos ◽  
John Konstantaras ◽  
Christos Pagkalos ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Energy Storage ◽  
Thermal Behavior ◽  
Latent Heat ◽  
Flow Rate ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Heat Transfer Fluid ◽  
Small Scale ◽  
Solidification Processes

A small-scale latent heat thermal energy storage (LHTES) unit for heating applications was studied experimentally using an organic phase change material (PCM). The unit comprised of a tank filled with the PCM, a staggered heat exchanger (HE) for transferring heat from and to the PCM, and a water pump to circulate water as a heat transfer fluid (HTF). The performance of the unit using the commercial organic paraffin A44 was studied in order to understand the thermal behavior of the system and the main parameters that influence heat transfer during the PCM melting and solidification processes. The latter will assist the design of a large-scale unit. The effect of flow rate was studied given that it significantly affects charging (melting) and discharging (solidification) processes. In addition, as organic PCMs have low thermal conductivity, the possible improvement of the PCM’s thermal behavior by means of nanoparticle addition was investigated. The obtained results were promising and showed that the use of graphite-based nanoplatelets improves the PCM thermal behavior. Charging was clearly faster and more efficient, while with the appropriate tuning of the HTF flow rate, an efficient discharging was accomplished.

scholarly journals Heat flow and heat transfer coefficient during crystallization under the pressure

2018 ◽  
Vol 157 ◽  
pp. 02036
Author(s):  
Richard Pastirčák ◽  
Ján Ščury ◽  
Tomáš Fecura
Keyword(s):  
Heat Transfer ◽  
Heat Flow ◽  
Solidification Process ◽  
Metal Mold ◽  
Transfer Coefficients ◽  
Microstructure Modeling ◽  
Heat Transfer Coefficients ◽  
Flow And Heat Transfer ◽  
Solidification Processes ◽  
Precise Prediction

Estimation of the heat flow at the metal-mold interface is necessary for accurate simulation of the solidification processes. For the numerical simulation, a precise prediction of boundary conditions is required to determine the temperature distribution during solidification, porosity nucleation, microstructure development, and residual stresses. Determination of the heat transfer coefficients at the metal-mold interface is a critical aspect for simulation of the solidification process and the microstructure modeling of the castings. For crystallization under the pressure and for thin-walled castings, HTC evaluation is important due to the very limited freezing time.

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