Wu Xuan, Gao Ting, Han Chenhui, Xu Jingsan, Owens Gary, Xu Haolan
Future Industries Institute, University of South Australia, Mawson Lakes Campus, SA 5095, Australia.
School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, QLD 4001, Australia.
Sci Bull (Beijing). 2019 Nov 15;64(21):1625-1633. doi: 10.1016/j.scib.2019.08.022. Epub 2019 Aug 22.
A solid photothermal reservoir is designed to implement solar-steam generation in the absence of bulk water. The photothermal reservoir is composed of a water absorbing core encapsulated by a photothermal reduced graphene oxide based aerogel sheet which absorbs light and converts it into heat thus evaporating the stored water. The photothermal reservoir is able to store 6.5 times its own weight in water, which is sufficient for one day solar evaporation, thus no external water supplement is required. During solar-steam generation, since no bulk water is involved, the photothermal reservoir minimizes heat conduction loss, and maximizes both of the exposed evaporation surface area and net energy gain from the environment, leading to an energy efficiency beyond the theoretical limit. An extremely high water evaporation rate of 4.0 kg m h (normalized to projection area) is achieved in laboratory studies over a cylinder photothermal reservoir with a diameter of 5.2 cm and a height of 15 cm under 1.0 sun irradiation. Practical evaluation of the photothermal reservoir outdoors as part of a desalination device demonstrates a similar evaporation rate where the salinity of the clean water produced is lower than 24 ppb. Thus the photothermal reservoir shows great potential for real world applications in portable solar-thermal desalination.
一种固体光热蓄热器被设计用于在没有大量水的情况下实现太阳能蒸汽产生。该光热蓄热器由一个吸水芯组成，该吸水芯被基于光热还原氧化石墨烯的气凝胶片包裹，这种气凝胶片吸收光并将其转化为热，从而蒸发储存的水。该光热蓄热器能够储存其自身重量6.5倍的水，这足以满足一天的太阳能蒸发需求，因此无需外部补水。在太阳能蒸汽产生过程中，由于不涉及大量水，光热蓄热器将热传导损失降至最低，并使暴露的蒸发表面积和从环境中获得的净能量增益都最大化，从而实现了超出理论极限的能量效率。在实验室研究中，对于一个直径为5.2厘米、高度为15厘米的圆柱形光热蓄热器，在1.0个太阳辐射强度下，实现了4.0千克·平方米·小时（归一化到投影面积）的极高水蒸发速率。作为海水淡化装置一部分的光热蓄热器在户外的实际评估表明，其蒸发速率相似，所产生的清洁水盐度低于24 ppb。因此，光热蓄热器在便携式太阳能热海水淡化的实际应用中显示出巨大潜力。
