| 1. |
- Li, Yuanji, et al.
(författare)
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Effect of pore density and filling ratio of metal foam on melting performance in a heat storage tank
- 2023
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Ingår i: Numerical Heat Transfer; Part A: Applications. - 1040-7782.
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Tidskriftsartikel (refereegranskat)abstract
- Thermal energy storage through solid–liquid phase change is an efficient method for mitigating solar energy intermittency by providing continuous energy supply for the end-users. However, the low thermal conductivity of phase change material, which serves as the heat transfer medium in the thermal energy storage systems, severely undermines the heat charging/discharging rates. Metal foam can significantly strengthen the heat storage performance via increasing the thermal conduction capability of phase change material and metal foam composite, mainly due to the large extension surface area and highly-conducting metallic ligaments of the metal foam. To squarely explore the influence of the two vital parameters (filling ratio and pore density) for the metal foam upon the phase change process, numerical models for describing the phase change process in a tank filled with phase change material and metal foam are established, and the experimental validations of the corresponding models are performed. Melting time, temperature uniformity, and heat storage capacity are selected as the targeted indexes for assessing and evaluating the impacts of filling ratio and pore density on the phase change process. The results show that the full melting time of heat storage decreases first and then increases with the decrease of filling ratio under any PPI. The smaller the PPI, the smaller the overall heat storage time. And the larger the PPI, the greater effect of the filling ratio on the heat storage time. The melting time of the PCM under the optimal filling ratio of 10 PPI and 100 PPI is shortened by 8.06% and 18.06%, and the temperature uniformity is reduced by 5.48% and 10.11%, respectively, compared with that of the complete filling.
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| 2. |
- Li, Yuanji, et al.
(författare)
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Experimental and numerical investigations on tilt filling design of metal foam in a heat storage tank
- 2023
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Ingår i: Renewable energy. - 0960-1481 .- 1879-0682. ; 217
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Tidskriftsartikel (refereegranskat)abstract
- The use of metal foam as a filler in heat storage tanks proves advantageous in compensating for the low thermal conductivity of phase change materials. However, the filling of metal foam can impede natural convection within the tank. Partially filled metal foam enables both strong natural convection in the upper pure phase change material region and enhanced thermal conductivity of the metal foam. This paper proposes inclining the upper surface of the metal foam to further strengthen natural convection in the upper region. Following experimental verification, a series of heat storage tanks with different metal foam inclination forms for latent heat storage were numerically simulated and compared. The results indicate that complete melting time was shortest for the case 5 (ab-type model with a = 0, b = 91.8), at 5320s, which represents an 18.8% reduction compared to benchmark case 9. Furthermore, comparison of the cases with inclined upper surfaces indicated that the clockwise inclination pattern resulted in greater time savings than the counterclockwise pattern. The results of this study offer valuable insights for the design of partially filled heat storage tanks.
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