A compact flat solar still with high performance

• Published in: International journal of heat and mass transfer Vol. 179; p. 121657
• Main Authors: Peng, Guilong, Sharshir, Swellam W., Hu, Zhixiang, Ji, Rencai, Ma, Jianqiang, Kabeel, A.E., Liu, Huan, Zang, Jianfeng, Yang, Nuo
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01-11-2021; Elsevier BV
• Subjects: Desalination; Flat solar still; Fresh water; Heat recovery; Insolation; Latent heat; Latent heat recovery; Mass transfer; Performance enhancement; Photovoltaic cells; Productivity; Solar cells; Solar desalination; Ultra-hydrophilic glass; Flat solar still; Ultra-hydrophilic glass; Latent heat recovery; Solar desalination
• ISSN: 0017-9310; 1879-2189
• DOI: 10.1016/j.ijheatmasstransfer.2021.121657

•A high-performance unconventional flat solar still (FSS) is proposed.•The condensate water in FSS is collected by using capillary grids and ultra-hydrophilic glass.•The daily productivity and energy efficiency of a double-stage FSS reach up to 7 kg/m2 and 72%, respectively.•The enhanced mass transfer in FSS by the compact structure is an important factor for the high performance.
Solar still is a convenient off-grid device for desalination, which can provide fresh water for families, ships, islands, and so on. The conventional inclined solar still (ISS) suffers from low efficiency and low productivity. To improve the performance of solar still, a flat solar still (FSS) is proposed, which has a working principle similar to the solar cell. The condensate water in FSS is collected by the capillary grid attached under the ultra-hydrophilic glass cover, instead of by gravity. Therefore, FSS avoids the inclined structure and is much more compact than ISS. The daily productivity of FSS reaches up to 4.3 kg/m2 under 6.3 kWh/m2 of solar insolation. Theoretical analysis shows that the enhanced mass transfer in FSS by the compact structure is an important factor for high performance. More interestingly, FSS can also be easily extended to more stages for latent heat recovery. The results show that the daily productivity and energy efficiency of a double-stage FSS reaches up to 7 kg/m2 and 72%, respectively, under 6.7 kWh/m2 of solar insolation, which is much higher than the conventional solar still. FSS paves a new way in designing and optimizing solar still.