Heat transfer enhancement for thermal energy storage using metal foams embedded within phase change materials (PCMs)
- School of Engineering, University of Warwick, CV4 7AL (United Kingdom)
In this paper the experimental investigation on the solid/liquid phase change (melting and solidification) processes have been carried out. Paraffin wax RT58 is used as phase change material (PCM), in which metal foams are embedded to enhance the heat transfer. During the melting process, the test samples are electrically heated on the bottom surface with a constant heat flux. The PCM with metal foams has been heated from the solid state to the pure liquid phase. The temperature differences between the heated wall and PCM have been analysed to examine the effects of heat flux and metal foam structure (pore size and relative density). Compared to the results of the pure PCM sample, the effect of metal foam on solid/liquid phase change heat transfer is very significant, particularly at the solid zone of PCMs. When the PCM starts melting, natural convection can improve the heat transfer performance, thereby reducing the temperature difference between the wall and PCM. The addition of metal foam can increase the overall heat transfer rate by 3-10 times (depending on the metal foam structures and materials) during the melting process (two-phase zone) and the pure liquid zone. The tests for investigating the solidification process under different cooling conditions (e.g. natural convection and forced convection) have been carried out. The results show that the use of metal foams can make the sample solidified much faster than pure PCM samples, evidenced by the solidification time being reduced by more than half. In addition, a two-dimensional numerical analysis has been carried out for heat transfer enhancement in PCMs by using metal foams, and the prediction results agree reasonably well with the experimental data. (author)
- OSTI ID:
- 21337883
- Journal Information:
- Solar Energy, Vol. 84, Issue 8; Other Information: Elsevier Ltd. All rights reserved; ISSN 0038-092X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
NATURAL CONVECTION
FORCED CONVECTION
FOAMS
METALS
PHASE CHANGE MATERIALS
LIQUIDS
MELTING
PARAFFIN
SOLIDIFICATION
LATENT HEAT STORAGE
EXPERIMENTAL DATA
SOLIDS
ZONES
HEAT FLUX
NUMERICAL ANALYSIS
THERMAL EQUILIBRIUM
DENSITY
WALLS
TWO-DIMENSIONAL CALCULATIONS
COOLING
PERFORMANCE
POROSITY
TEMPERATURE GRADIENTS
AUGMENTATION
Metal foams
Pore size
Non-thermal equilibrium