Poredoš Primož, Gao Jintong, Shan He, Yu Jie, Shao Zhao, Xu Zhenyuan, Wang Ruzhu
Institute of Refrigeration and Cryogenics, Shanghai Jiao Tong University, 200240, Shanghai, China.
Engineering Research Center of Solar Power & Refrigeration, MOE China, 200240, Shanghai, China.
Nat Commun. 2024 Sep 10;15(1):7890. doi: 10.1038/s41467-024-51880-y.
Passive solar membrane distillation (MD) is an emerging technology to alleviate water scarcity. Recently, its performance has been enhanced by multistage design, though the gains are marginal due to constrained temperature and vapor pressure gradients across the device. This makes condenser cooling enhancement a questionable choice. We argue that condenser heating could suppress the marginal effect of multistage solar MD by unlocking the moisture transport limit in all distillation stages. Here, we propose a stage temperature boosting (STB) concept that directs low-temperature heat to the condensers in the last stages, enhancing moisture transport across all stages. Through STB in the last two stages with a heat flux of 250 W m, a stage-averaged distillation flux of 1.13 L m h S was demonstrated using an 8-stage MD device under one-sun illumination. This represents an 88% enhancement over the state-of-the-art 10-stage solar MD devices. More notably, our analysis indicates that 16-stage STB-MD devices driven by solar energy and waste heat can effectively compete with existing photovoltaic reverse osmosis (PV-RO) systems, potentially elevating freshwater production with low-temperature heat sources.
被动式太阳能膜蒸馏（MD）是一种缓解水资源短缺的新兴技术。最近，通过多级设计提高了其性能，不过由于整个装置的温度和蒸汽压力梯度受限，收益甚微。这使得增强冷凝器冷却成为一个值得怀疑的选择。我们认为，冷凝器加热可以通过消除所有蒸馏阶段的水分传输限制来抑制多级太阳能MD的边际效应。在此，我们提出一种阶段温度提升（STB）概念，即将低温热量导向最后阶段的冷凝器，增强各阶段的水分传输。通过在最后两个阶段采用250 W m的热通量进行STB，在单太阳光照下使用8级MD装置实现了1.13 L m h S的阶段平均蒸馏通量。这比最先进的10级太阳能MD装置提高了88%。更值得注意的是，我们的分析表明，由太阳能和废热驱动的16级STB-MD装置可以有效地与现有的光伏反渗透（PV-RO）系统竞争，有可能利用低温热源提高淡水产量。
