Comprehensive numerical modeling of intermittent flow cooling with enhanced photovoltaic efficiency in PVT/NPCM systems

Abstract

The photoelectric conversion efficiency of photovoltaic thermal (PVT) systems is a key concern in solar energy research. The widespread use of continuous nanofluid cooling in PVT/NPCM (Nano-Enhanced Phase Change Material) systems leads to heightened energy consumption. In order to improve efficiency of the PVT/NPCM systems, a two-dimensional transient heat transfer numerical model is established to analyze the PVT/NPCM system with intermittent flow cooling. Corresponding govern equations with boundary conditions are proposed, and numerically solved by using the finite element method. Simulation results are compared with experimental data, showing a deviation of less than 7 %. The findings indicate that the intermittent cooling reduces the flow energy consumption required to drive 2220 L of nanofluid compared to continuous cooling over a 7-h period. Furthermore, under intermittent cooling conditions, the average electrical efficiency stands at approximately 19.7 %. Notably, the electrical efficiency of PVT/NPCM systems employing intermittent flow cooling closely aligns with those employing continuous flow cooling, exhibiting a maximum deviation of merely 0.0348 %. Additionally, intermittent flow cooling emerges as a favorable choice under solar radiation intensities surpasses 1000W/m2, enabling a significant reduction in overall energy consumption while maintaining commendable cooling performance.