Wang Zhangxin, Horseman Thomas, Straub Anthony P, Yip Ngai Yin, Li Deyu, Elimelech Menachem, Lin Shihong
Department of Civil and Environmental Engineering, Vanderbilt University, Nashville, TN 37235, USA.
Department of Chemical and Environmental Engineering, Yale University, New Haven, CT 06520-8286, USA.
Sci Adv. 2019 Jul 26;5(7):eaax0763. doi: 10.1126/sciadv.aax0763. eCollection 2019 Jul.
Solar-thermal desalination (STD) is a potentially low-cost, sustainable approach for providing high-quality fresh water in the absence of water and energy infrastructures. Despite recent efforts to advance STD by improving heat-absorbing materials and system designs, the best strategies for maximizing STD performance remain uncertain. To address this problem, we identify three major steps in distillation-based STD: (i) light-to-heat energy conversion, (ii) thermal vapor generation, and (iii) conversion of vapor to water via condensation. Using specific water productivity as a quantitative metric for energy efficiency, we show that efficient recovery of the latent heat of condensation is critical for STD performance enhancement, because solar vapor generation has already been pushed toward its performance limit. We also demonstrate that STD cannot compete with photovoltaic reverse osmosis desalination in energy efficiency. We conclude by emphasizing the importance of factors other than energy efficiency, including cost, ease of maintenance, and applicability to hypersaline waters.
太阳能热淡化（STD）是一种在缺乏水和能源基础设施的情况下提供高质量淡水的潜在低成本、可持续方法。尽管最近通过改进吸热材料和系统设计来推进STD，但最大化STD性能的最佳策略仍不明确。为了解决这个问题，我们确定了基于蒸馏的STD中的三个主要步骤：（i）光到热能转换，（ii）热蒸汽产生，以及（iii）通过冷凝将蒸汽转化为水。使用特定水生产率作为能源效率的定量指标，我们表明有效回收冷凝潜热对于提高STD性能至关重要，因为太阳能蒸汽产生已经接近其性能极限。我们还证明，STD在能源效率方面无法与光伏反渗透淡化竞争。我们最后强调了除能源效率之外的其他因素的重要性，包括成本、维护简易性以及对高盐水的适用性。
