Comparative study on heat transfer characteristics of molten PCM in PV/PCM air-based system based on grey relation analyses

Abstract

The operating temperature of photovoltaic (PV) panel have significant influence on its generating efficiency and life span. To improve the performance of PV panel, we performed comparative analyses on a novel PV panel cooling strategy by integrating PV panel with phase change material (PCM) and ventilation system (PV/PCM air-based system). The heat transfer characteristics of molten PCM in an inclined cavity with constant heat flux on one side and air flow boundary on another side are numerically investigated. The thermal performance including dimensionless temperature and temperature uniformity, the heat transfer capability including local Nusselt number and average Nusselt number, are compared and analyzed. The results indicate that flow boundary has a significant effect on the PV cooling. Cavity at top-down flow direction has better temperature uniformity and at bottom-up flow direction has greater heat transfer capability. Increasing Reynolds number can enhance the heat transfer efficiency and reduce the temperature at the same time. Further, the impact of each factor on heat transfer capability are quantified based on the grey relation analyses. Grey relation grade for average Nusselt number with Ra number, Re number, AR, ϕ, and flow direction is 0.51, 0.66, 0.69, 0.62, and 0.53, respectively. This indicates that heat transfer capacity is the most sensitive to AR, followed by Re number, inclination angle, flow direction, and Ra number.

Keywords:

• Forced convection
• grey relational analysis
• heat transfer
• inclined cavity
• molten phase change material
• natural convection

Additional information

Funding

This research was funded by the Cooperation Research Project of Sichuan University and Yibin City, China (Project No. 2020CDYB-16).