| Summary: | 碩士 === 國立中央大學 === 機械工程研究所 === 98 === This study investigates the thermal and flow characteristics of an energy storage system using phase-change materials (PCM). The governing dimensionless equations of the problem and boundary conditions are formulated and solved numerically by using the enthalpy-porosity method with the control volume approach. The melting process, the total melting time, and the effects of several parameters are discussed. The dimensionless parameters considered include the Peclet number, the Stefan number, the aspect ratio, and the thermal conductivity ratio of the PCM to the heat transfer fluid.
Results show that, for cases of high Peclet number, high Stefan number or high thermal conductivity ratio, the melting time is reduced due to the enhancement of heat transfer and the circulation of the PCM. For intermediate and high temperature PCM energy storage systems, KF is the best material to use.
Correlations between the dimensionless total melting time of the PCM and the Peclet number, Stefan number, aspect ratio and the thermal conductivity ratio are also derived for different conditions.
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