Numerical model of PCM heat exchange based on dynamic boundary

Abstract

Using phase change material (PCM) to store solar energy can effectively alleviate energy and environmental problems. The accurate numerical models are the guarantee to promote the practical application of hydrated salt PCM. However, the phenomenon of supercooling and phase change hysteresis makes the PCM present various operating states under the actual dynamic inlet boundary conditions, which makes it difficult to solve the temperature field. In this study, a numerical model is established, which can independently determine whether each computing node is in the heating mode, the cooling mode, the heating after partial solidification mode, or the cooling after partial melting mode at each moment. The calculation codes for the first two modes in the model have been verified experimentally, and the latter two modes are modeled using the curve scale method proven to be the most accurate. To test the running process of the numerical model, a dynamic inlet boundary condition was constructed and input. The operation results show that the numerical model can smoothly switch the mode of each node and then solve it.

Keywords

• Phase change modeling
• Dynamic boundary
• Partial phase change cycle
• Heat storage
• Numerical simulation