Photovoltaic Minichannel Cooling Using Pulsating Ternary Hybrid Nanofluids: A Two-Phase CFD Study with Discrete Ordinates Radiation Modelling

Managing the temperature of photovoltaic modules is essential for limiting efficiency losses under high solar loading. This work evaluates a minichannel-based cooling system using a ternary hybrid nanofluid subjected to periodic inlet-flow modulation. Its performance is benchmarked against natural convection, water cooling, and steady mono-, binary-, and ternary-nanofluid circulation. The numerical methodology integrates three-dimensional transient CFD, discrete ordinates radiation, a multiphase mixture formulation for nanoparticle–fluid slip, and a temperature-dependent single-diode model. Simulations were conducted at a mean Reynolds number of 50, with the pulsation amplitude varied from 0.3 to 0.8 and the Strouhal number from 1 to 10. Electrical quantities were calculated using cycle-averaged PV temperatures after periodic flow behaviour was established. The best-performing pulsating case, obtained at A = 0.5 and St = 5, limited the maximum PV temperature to approximately 314.7 K. This value was about 1.6 K below that achieved with steady ternary hybrid nanofluid flow and 5 K below that obtained with water. The corresponding maximum electrical power, electrical efficiency, and exergetic efficiency were approximately 4.0 W, 22.4%, and 23.8%, respectively. Periodic acceleration and deceleration enhanced coolant redistribution, repeatedly redeveloped the thermal boundary layer, and reduced downstream heat accumulation. The principal contribution is the integrated transient evaluation of pulsating ternary hybrid nanofluid cooling within a common CFD–radiation–electrical–exergy framework. Pulsation reduced the maximum PV temperature by approximately 1.6 K relative to steady ternary hybrid nanofluid cooling, confirming an additional but incremental benefit rather than a dominant improvement over steady liquid cooling.