A review on condensation enhancement techniques for accelerating the evaporation performance of solar desalination system

Abstract

Solar energy is a crucial driver of freshwater productivity in solar stills (SSs). While extensive efforts have been devoted to advancing latent and sensible heat storage, nano-based photothermal absorbers, and solar concentrators, comparatively limited attention has been given to improving the condensation process, which remains a critical bottleneck in SS performance. This review addresses this gap by focusing on efficient condensation enhancement techniques reported between 2020 and 2023. Specifically, it highlights three key areas: (i) nanostructured treatments on condensing covers, (ii) integrated external condensers and thermoelectric cooling, and (iii) water-flow cooling on condensation surfaces. These approaches improve droplet removal, sustain larger temperature gradients, and accelerate phase-change processes, collectively contributing to higher freshwater yield. Beyond summarizing performance metrics, this work provides a comparative analysis of advantages, disadvantages, exergy/energy implications, and temperature sensitivity of each technique, framed within the thermodynamic and psychrometric principles governing SS operation. The review underscores that while notable progress has been achieved, research on robust, non-contaminating surface modifications and cost-effective scalable solutions is still limited. Broadly, this work emphasizes that advancing condensation strategies is essential not only for improving the efficiency of solar stills but also for enabling practical, low-cost, and sustainable freshwater generation in water-scarce regions worldwide.