image: The tilted 3D solar heaters enhance solar energy harvesting in practical applications, the directional vapor escaping between solar heater arrays is significantly enhanced, allowing thinner air layer and significantly enhances the conductive heat transport Qcon.
Credit: ©Science China Press
This study is led by Prof. Zhenyuan Xu and Prof. Ruzhu Wang (Engineering Research Center of Solar Power and Refrigeration (MOE), Institute of Refrigeration and Cryogenics, Shanghai Jiao Tong University). The theoretical analysis and laboratory, outdoor field and scalability tests were performed.
Freshwater scarcity is a global challenge, with solar evaporation emerging as a sustainable solution for water treatment. Advances in thermally-localized heating have expanded its application in desalination, steam generation, and wastewater treatment. However, conventional porous evaporators face significant fouling issues that threaten long-term stability. While anti-fouling materials, structural modifications, and system design improvements have mitigated some challenges, these approaches are often scenario-specific and limited in adaptability. Contactless solar evaporation, which physically separates the solar heater from the liquid, offers a promising anti-fouling solution with low cost and high versatility. Nevertheless, its performance remains constrained by heat transport limitations and overlooked mass transport inefficiencies, particularly in scalable applications.
To address these limitations, researchers proposed a 3D contactless solar evaporation design that optimizes both heat and mass transport. Using equivalent transport resistance analysis, the study revealed mass transport as the primary bottleneck in scalable systems. The 3D structure enhances upward vapor transport through directional pathways, enabling thinner air layers and improved energy transfer. This design achieved a high evaporation rate of 1.03 kg m-2 h-1 under one-sun illumination, 110% higher than conventional 2D designs. Dark evaporation rates also tripled to 0.15 kg m-2 h-1, critical for non-sunlight operation. Outdoor tests demonstrated an average evaporation rate of 1.21 kg m-2 h-1 (589.98 W m-2), 133% higher than conventional designs. The performance variation between small and large devices is minimal (3%), highlighting its potential for scalable and contamination-resistant applications in diverse water treatment scenarios.
See the article:
High-performance and scalable contactless solar evaporation with 3D structure
https://doi.org/10.1016/j.scib.2024.11.051
Journal
Science Bulletin