The cooling system of a car engine effects strongly the efficiency of the car engine so many studies were presented to enhance the cooling system of the car. The components of the cooling system are radiator, water pumps, fan, shutters, thermostats, expansion tanks/storage tanks, water pipes, water temperature gauges, etc. Among these components, the radiator considers the primary key to enhancing the efficiency of the car engine. Many studies were achieved to enhance the efficiency of car radiators by using different nanofluids as a coolant are discussed in this literature review study. These previous studies investigated various kinds of nanofluids such as Al2O3, CuO, TiO2, SiO2, and ZnO with different base fluids. Nanofluid concentrations, nanofluid temperature, and nanofluid flow rate were studied by previous studies eleven years ago.
In this paper, turbulent forced convection of nanofluid flow in channel with isoscelestriangularbaffles is numerically investigated over Reynolds number ranges of 5000-10000.One baffle mounted on the bottom wall of channel and another mounted on the top wall.Al2O3-water nanofluid with nanoparticles volume fraction of 4% and nanoparticles diametersof 25 nm is used. The governing continuity, momentum and energy equations as well as thelow Reynolds number k-ε model of Launder and Sharma have been solved using finitevolume method. The effect of baffle height, baffle distance as well as Reynolds number onthe flow and thermal characteristics have been presented and discussed. It is found that theenhancement ratio of the average Nusselt number as well as the fraction factor increase withincreasing in the baffles height. It is also found that the enhancement ratio of the averageNusselt number increases as the distance of top baffle decrease. Furthermore, the bestthermal-hydraulic performance of channel with triangular baffles using nanofluid can beobtained at baffle height of 2.5 mm, distance of the top baffle of 40 mm and Reynoldsnumber of 5000.
These systems show great promise by converting waste heat from photovoltaic modules into additional electrical power. The study analyzes the performance and efficiency of the hybrid PV-TEG systems under varying conditions, such as different solar concentration ratios, cooling methods, and materials. While these innovations promise to improve system efficiency, the review also identifies several challenges, including increased thermal resistance, higher system costs, and the minimal temperature difference across the TEG, which significantly limits its performance. This limitation, where the temperature differential is often too small to be effectively harnessed, reduces the TEG's overall efficiency and hinders the integrated system's potential gains. The review underscores the need for urgent and extensive research to develop optimized design configurations, durable mathematical models, and further experimental validation to ensure the practical viability of these systems under diverse environmental conditions. Despite these challenges, the potential of PV-TEG systems to revolutionize solar energy technologies is undeniable.PV-TEG performance is intricately linked to environmental conditions: higher solar radiation boosts efficiency, but increased ambient temperatures reduce it. TEGs often hinder PV cooling, yielding minimal efficiency gains. Non-uniform heat and low-temperature differences across TEGs further decrease performance. While hybrids can improve power conversion, high costs limit feasibility. However, with strategies such as enhancing solar concentration, using effective cooling methods like water or nanofluids, and advanced materials like phase change materials, the efficiency and reliability of these systems can be significantly improved
In this paper, turbulent convective heat transfer in a triangular-ribbed chan-nel has been numerically investigated. SiO2-water with nanoparticles volume fraction of 4% and nanoparticles diameters of 30 nm is employed with Reyn-olds number ranging from 2000 to 8000. The governing continuity, momen-tum and energy equations in addition to low Reynolds number k-ε model have been transformed into body-fitted coordinates system and then solved using finite volume method. The effects of Reynolds number and rib heights on Nusselt number, pressure drop, thermal-hydraulic performance factor and entropy generation are presented and discussed. It is observed that the Nusselt number, pressure drop and thermal performance increase with in-creasing of Reynolds number and rib height. In addition, the highest perfor-mance factor can be obtained at Reynolds number of 6500 and rib height of 1.5 mm.