Improving photovoltaic (PV) panel performance under extreme climatic conditions is critical for advancing sustainable energy systems. In hyper-arid regions, elevated operating temperatures significantly reduce panel efficiency. This study investigates and compares three cooling techniques—air cooling, water cooling, and porous media cooling—using thermal and electrical modeling based on CFD simulations in ANSYS. The numerical model replicates a PV system operating under peak solar irradiance (900 W/m²) and realistic ambient conditions in Adrar, Algeria. Simulation results show that air cooling leads to a modest temperature reduction of 6 °C and a marginal efficiency gain of 0.25%. Water cooling, employing a top-down laminar flow, reduces cell temperature by over 35 °C and improves net electrical output by 30.9%, despite pump energy consumption. Porous media cooling, leveraging passive evaporation through gravel, decreases panel temperature by around 30 °C and achieves a net output gain of 26.3%. Mesh sensitivity and validation against experimental data support the accuracy of the model. These findings highlight the significant potential of water and porous material cooling strategies to enhance PV performance in hyper-arid environments. The study also demonstrates that porous media can deliver high thermal effectiveness with minimal energy input, making it a suitable low-cost option for off-grid applications. Future work will integrate long-term climate data, real diffuser geometries, and experimental validation to further refine these models.

1. Industrial rotary dryers equipped with combustion chambers are among the most energy-intensive unit operations in process industries, with reported thermal efficiencies ranging between 30% and 7...

Piston top rings in the combustion engine play a crucial role in the overall hydrodynamic performance of engines, such as power loss, minimum film thickness and friction forces, by ensuring sealing and minimizing the leakage of burnt gases. This present paper examines the influence of four key parameters of the top ring, such as ring width, ring temperature, ring tension, and ring surface roughness on the hydrodynamic behavior at the ring/cylinder contact. These parameters play a significant role in the formation and maintenance of the oil film, directly influencing hydrodynamic indicators such as the minimum oil film thickness, friction force, power loss, oil pressure, and the ring angle twist. This article relies on hydrodynamic models and numerical simulations performed using GT-SUITE version 6 software to analyze these effects. The pressure curve used in this simulation is experimentally validated for an engine speed of 2000 RPM. It was found that an increase in the top ring temperature reduces the oil’s viscosity, decreasing the film thickness and increasing the risk of metal-to-metal contact. Increasing the roughness of the ring enhances oil film stability, especially at the bottom dead center (BDC) points during each phase of the operating cycle. Further, three different types of ring profiles were investigated for friction forces by varying the speed of the engine.

This study presents a comprehensive thermo-energetic and exergetic assessment of a 250 MW steam boiler in a Cuban thermal power plant, operating under partial load conditions (plant: 62–66%; boiler: 58–61%). An integrated diagnostic methodology was developed and implemented in Mathcad 15 to evaluate key performance indicators, including thermal efficiency (η_tGV); exergetic efficiency (η_ExGV); exergy destruction ratio (γ_ExGV); steam generation index (IG_v); and specific fuel consumption (B_Esp). The methodology was applied to two fuels with contrasting thermophysical and chemical properties: fuel oil and Enhanced Crude Oil 650. The results indicate superior performance with fuel oil due to its higher heating value; however, efficiency losses were mainly attributed to operational factors such as excessive air supply (22.7–26.4%), heat transfer surface fouling, and inadequate maintenance. The analysis revealed significant deviations from design values—thermal efficiency (90.27–90.59%) and exergetic efficiency (<60%)—highlighting an untapped potential for energy savings. Quantitative estimates indicate potential annual fuel cost savings of approximately 1.2 million USD through optimized combustion and maintenance practices. The proposed framework enables accurate diagnostics of complex boiler systems and provides actionable indicators to support combustion optimization and energy efficiency strategies in conventional thermal power plants.