Nanoparticles play a crucial role in enhancing the thermal and rheological properties of nanofluids, making them a valuable option for increasing the efficiency of heat exchangers. This research explores how nanoparticle characteristics, such as concentration, size, and shape, impact the properties of nanofluids. Nanofluids' thermophysical properties and flow characteristics are essential in determining heat transfer efficiency and pressure loss. Nanoparticles with high thermal conductivity, such as metallic oxides like MgO, TiO₂, and ZnO, can significantly improve the heat transfer efficiency by around 30% compared to the base fluid. The stability of nanofluids plays a crucial role in their usability. Various methods, such as adding surfactants, using ultrasonic mixing, and controlling pH, have been employed to enhance the stability of nanofluids. The desired thermophysical properties can be achieved by utilizing nanofluids to enhance the system's heat transfer efficiency. Modifying the size and shape of nanoparticles also considerably improves thermal conductivity, affecting nanofluid viscosity and density. Equations for determining heat transfer rate and pressure drop in a double-pipe heat exchanger are discussed in this review, emphasizing the significance of nanofluid thermal conductivity in influencing heat transfer efficiency and nanofluid viscosity in impacting pressure loss. This Review identifies a trend indicating that increasing nanoparticle volume concentration can enhance heat transfer efficiency to a certain extent. However, surpassing the optimal concentration can reduce Brownian motions due to higher viscosity and density. This Review offers a viable solution for enhancing the thermal performance of heat transfer equipment and serves as a fundamental resource for applying nanofluids in heat transfer applications.

The ongoing trend towards miniaturizing electronic devices and increasing their power densities has created substantial challenges in managing the heat they produce.

Solar stills represent a crucial technology in the quest to provide clean and accessible water, particularly in regions facing water scarcity and limited energy resources. This study investigates various solar still designs, exploring their advantages and limitations in water purification. Through an analysis of the current global landscape of solar still usage and ongoing research endeavors, this study aims to highlight the potential of solar stills and propose modifications to enhance their efficiency. The study also investigates various extensive analysis of diverse solar still designs and their performance metrics, including factors like reflectors, wick materials, absorber plates, and air velocity, this study elucidates key strategies to augment water output and energy utilization. Reflectors and pebbles, variations in wick materials, and modifications in absorber plate design have shown promising results in increasing productivity. Additionally, insights into the impact of environmental variables such as solar radiation, wind velocity, and ambient temperature on solar still performance are provided, informing the design optimization process. Through an analysis of global usage patterns and ongoing research efforts, this study highlights the untapped potential of solar stills and proposes strategies to enhance their performance. Furthermore, it suggests avenues for future research, including the integration of heat storage materials and the development of advanced modeling and control algorithms, to further enhance the performance of solar stills. Through these efforts, solar stills can emerge as a sustainable and reliable solution for water purification, contributing significantly to global efforts to combat water scarcity.