Entropy based optimization of mini-channel heat sinks with advanced ternary nanofluids for photovoltaic cells and geometrical enhancements

• A novel geometrical optimization approach for mini-channel heat sinks (MCHS) is proposed using entropy-based analysis. • COMSOL Multiphysics and the Finite Element Method (FEM) were utilized to simulate the hydrothermal performance of five MCHS geometries. • The optimized Case 4 geometry achieved a 27.94 % improvement in heat transfer and a 29.71 % reduction in thermal resistance. • Integration of ternary hybrid nanofluids significantly enhanced cooling efficiency for photovoltaic cells. • The optimal configuration was identified as Re = 536.8, Tin = 300.3 K, ϕ = 0.079, and SF = 15.81, minimizing entropy generation. This study introduces a novel technique with the implementation of a ternary hybrid nanofluid using optimized geometrical configuration and demonstrating superior improvement in heat transfer efficiency and minimization of entropy compared to conventional cooling methods. In this paper, 3D simulations are carried out in COMSOL Multiphysics to investigate the hydrothermal performance of the mini-channel heat sink applied to photovoltaic cells. The five geometrical configurations were studied to optimize heat transport and minimize pressure drop with a ternary hybrid nanofluid composed of GO and MgO/Al₂O₃ as the working fluid. The results showed that geometrical changes in the mini-channel heat sink significantly impact the thermal performance, and case 4 shows higher heat transfer efficiency. The key parameters, such as Reynolds Number ( Re ), inlet temperature (T in ), nanoparticle volume fraction and nanoparticle shape factor (SF) are optimized for the reduction of entropy generation (Ns,a) using the Taguchi method and Response Surface Methodology. Optimization results identified the most feasible combination of Re = 536.8, T in =300.3 K, ϕ=0.079, SF=15.81, which gives lower thermal and flow irreversibilities. This work points out the potential of ternary hybrid nanofluid and optimized mini-channel heat sink designs to advance thermal management systems and is very practical, providing insights into possible applications in electronics, solar panels, and energy storage devices.