ABSTRACT Solar stills provide a simple, low‐cost, and sustainable solution for freshwater production in arid and water‐scarce regions. However, their widespread adoption remains constrained by low freshwater productivity. The present study numerically investigates the effect of film cooling on the thermal performance and freshwater productivity of a conventional solar still. A transient two‐dimensional finite‐difference model is developed to solve the coupled energy equations governing the system components, providing high‐fidelity spatial and temporal representations of the temperature field and the freshwater productivity. The numerical model is validated against experimental data available in the literature. The results show that the glass‐cover cooling technique increases the maximum water‐to‐glass temperature difference from 8.31°C to 18.15°C. In addition, the daily freshwater productivity increases from 2.69 to 3.20 kg.m −1 .day −1 , representing an improvement of 18.95%. The average energy efficiency also increases from 24.24% to 29.18%. Furthermore, a parametric analysis identifies an optimal cooling‐water film thickness of 5 mm and a volumetric flow rate of 0.1 L.s −1 .
ABSTRACT The rapid advancement of modern electronics resulted in intensified thermal management challenges, and positioned microchannel heat sinks (MCHSs) as a promising technology to dissipate high heat fluxes in next generation electronics. This review critically examines recent developments in passive thermo‐hydraulic enhancement of MCHSs, with emphasis on three major approaches: channel geometry modification, internal flow modifying structures, and working fluid enhancement. The reviewed studies are synthesized according to their underlying heat transfer mechanisms, including secondary flow generation, boundary layer redevelopment, vortex‐induced mixing, wake interaction, recirculation, and increased effective heat transfer area. Particular emphasis is placed on the balance between heat transfer enhancement and hydraulic losses, as an increase in Nusselt number alone does not necessarily indicate better thermo‐hydraulic performance. The review considers integrated and hybrid enhancement configurations, as the combined use of different flow disturbing elements provided improved heat transfer with properly designed interaction. Excessive flow blockage resulted in a pressure drop penalty and reduces the overall benefit. Nanofluids and hybrid nanofluids are also discussed, considering their potential to enhance thermal performance as well as practical concerns such as stability, increased viscosity, particle sedimentation, and higher pumping requirements. In addition, emerging AI/ML approaches are reviewed across performance prediction, deep learning, physics‐informed modelling, surrogate‐assisted optimization, reinforcement learning, and CFD–ML frameworks. The analysis indicates that AI/ML can accelerate design exploration and optimization within defined parameter domains, but limitations associated with dataset quality, extrapolation, uncertainty, and independent validation remain. Finally, key research gaps involving experimental validation, manufacturability, multi‐parameter optimization, transient thermal behavior, uncertainty quantification, and intelligent thermal control are identified. The review provides an integrated perspective for developing high performance and practically viable MCHSs for next‐generation electronics cooling.
ABSTRACT This study explores recent advances in cord‐based wick systems that regulate water depth in distillers, a key parameter influencing desalination performance. Maintaining a shallow water layer generally improves output, and cord wick technology minimizes thermal losses by selectively absorbing only the saline water that evaporates. Several design modifications—including reflectors, air‐circulation fans, and baffles integrated with phase change materials (PCMs)—have substantially increased the efficacy of cord‐wick distillers. For instance, a configuration combining cords, mirrors, a fan, and baffles achieved a 264% rise in freshwater yield. Beyond productivity gains, these improvements also provide ecological benefits, including an estimated annual reduction of approximately 28.71 tons of CO 2 emissions, as well as water purification costs ranging from USD 0.01 to 0.0185 per liter. These findings support continued efforts to maximize desalination efficiency through cord wick‐based approaches in solar distillation systems. Our work demonstrates a strong commitment to advancing the United Nations Sustainable Development Goals (SDGs), particularly SDG 6: Clean Water and Sanitation.
ABSTRACT Solar distillation is one of the simplest and cheapest technologies for producing fresh water from saline or brackish water in remote and arid regions. Nevertheless, the daily productivity of the conventional solar still remains low, which restricts its commercial deployment. Among the numerous augmentation techniques, mirrors and reflectors have attracted wide attention because they are inexpensive, simple to install, and capable of considerably intensifying the solar radiation received by the evaporation zone. This review surveys the recent experimental and theoretical studies that employed internal and/or external reflectors to enhance solar still performance. Unlike previous reviews that classified the literature according to the reflector position, the present work classifies the studies according to the solar still configuration, covering conventional single‐slope, stepped, trays, inclined wick, pyramid, hemispherical, spherical, half‐cylindrical, conical, tubular, coiled, rotating wick belt, and rotating discs solar stills. For each configuration, the design modifications, operating conditions, and the attained gains in productivity and thermal efficiency are presented and compared. The survey reveals that reflectors alone typically raise the distillate yield by about 20%–60%, while their combination with other augmentation tools, such as wick materials, baffles, external condensers, fans, and nano‐enhanced phase change materials, can push the overall enhancement beyond 150%–300% with daily yields exceeding 10 L/m 2 ·day in several configurations. The review is closed by a comprehensive comparison table, the main conclusions, and recommendations for future research. My research demonstrates a strong commitment to advancing the United Nations SDGs (Sustainable Development Goals), particularly Clean Water and Sanitation (SDG 6): and Affordable and Clean Energy (SDG 7).
ABSTRACT Hybrid draft cooling systems have emerged as an alternative for balancing cooling‐water consumption and thermal performance, but the existing literature remains fragmented across performance optimization, system configuration, and thermal‐flow analysis. This systematic review addresses this gap by synthesizing and critically comparing 30 peer‐reviewed studies published from 2015 to 2026, selected from 85 initially identified records using the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA) framework. The reviewed studies were organized into three interconnected themes: performance optimization and predictive modeling, system design and configuration, and thermal‐flow performance and operational analysis. The comparative synthesis shows that natural‐draft hybrid configurations can reduce water consumption by more than 95% relative to wet cooling under the reported conditions, although this benefit may involve an annual economic penalty of approximately US$15.46 million. For mechanically assisted systems, optimized fan operation has been associated with more than 50% energy savings, while hybrid mechanistic–machine‐learning models have achieved predictive accuracy of R 2 > 0.99. Design‐oriented studies further indicate that internal dry‐zone integration can reduce visible plume area by 45.5%, whereas mechanical‐draft hybrid configurations have reported water savings of 5.9%–14.4% with an outlet thermal‐performance penalty of 0.8°C–1.0°C. These findings demonstrate that hybrid‐cooling performance is governed by coupled water allocation, airflow resistance, ambient conditions, dry‐zone configuration, and auxiliary‐fan operation rather than by a single design parameter. The review also identifies persistent gaps in long‐term fouling characterization, adaptive control, multiobjective optimization, life‐cycle cost assessment, and transferability across climatic and operational conditions. The resulting synthesis provides a quantitative basis for evaluating water–energy–thermal trade‐offs and for developing more adaptable and economically viable hybrid draft cooling systems.
