Case Studies in Thermal Engineering (Aug 2024)
Investigating the enhanced cooling performance of ternary hybrid nanofluids in a three-dimensional annulus-type photovoltaic thermal system for sustainable energy efficiency
Abstract
For the growth of sustainable energy, increasing the efficiency of photovoltaic/thermal (PV/T) systems is still essential. Particularly ternary hybrid nanofluids have shown promise as a means of improving the systems' electrical and thermal performance. This study delves deeply into the exploration of a three-dimensional annulus-type Photovoltaic Thermal (PV/T) system, centering on its cooling function through the utilization of ternary hybrid nanofluids featuring diverse nanomaterial shapes. The system structure involves a circular cylinder enveloped within glass, silicon, and copper layers, forming the core of the PV panel. The investigation employs COMSOL Multiphysics 6.0 with boundary conditions like radiative heat flux on the upper domain. Nanofluids with varied shapes (spherical, brick-like, cylindrical, platelet, and blade-shaped) comprising copper, aluminum oxide, and micro-wall carbon Nanotubes suspended in water are scrutinized as the base fluid. Using COMSOL Multiphysics, our simulation employs a conjugate heat transfer interface to solve the intricate three-dimensional Navier-Stokes equations and energy equations, addressing the combined convection challenges in the system. Analyzing parameters such as Reynolds number (100–1500), aspect ratios (0.1, 0.15, 0.2), shape factors (3–8.9), and total volume fractions of nanomaterials (1%–10 %), we noted a significant decline (21–28 %) in the average Nusselt number as nanoparticle concentration increased. This trend highlights strengthened convection processes, notably observable with increased flow pipe diameter or aspect ratio. This decrease suggests that the system's convective heat transfer efficiency has decreased. Nonetheless, because the PV cells are better cooled, the decrease in convective heat transfer is accompanied by an increase in the electrical efficiency of the system. The practical implication of this trend is that even though the thermal performance in terms of heat removal may decline, the overall cooling effect still helps to keep the PV cells' temperature down, thereby raising their electrical output. The study revealed enhanced electrical efficiency (up to 9.3834 %) with blade-shaped particles under specific conditions: Re = 1500, 10 % volume fraction, and an aspect ratio of 0.1. Additionally, the investigation suggests a potential for achieving a maximum thermal efficiency of 85.62 %. These findings underline the promising impact of nanomaterial manipulation on both electrical and thermal efficiencies within the PV/T system while the maximum temperature at the outlet reaced to 5.470 C.
