Wetsus, Centre of Excellence for Sustainable Water Technology, P.O. Box 1113, 8900 CC Leeuwarden, The Netherlands.
Environ Sci Technol. 2011 Aug 15;45(16):7089-95. doi: 10.1021/es2012758. Epub 2011 Jul 20.
The mixing of sea and river water can be used as a renewable energy source. The Gibbs free energy that is released when salt and fresh water mix can be captured in a process called reverse electrodialysis (RED). This research investigates the effect of the intermembrane distance and the feedwater flow rate in RED as a route to double the power density output. Intermembrane distances of 60, 100, 200, and 485 μm were experimentally investigated, using spacers to impose the intermembrane distance. The generated (gross) power densities (i.e., generated power per membrane area) are larger for smaller intermembrane distances. A maximum value of 2.2 W/m(2) is achieved, which is almost double the maximum power density reported in previous work. In addition, the energy efficiency is significantly higher for smaller intermembrane distances. New improvements need to focus on reducing the pressure drop required to pump the feedwater through the RED-device using a spacerless design. In that case power outputs of more than 4 W per m(2) of membrane area at small intermembrane distances are envisaged.
海水和河水的混合可以作为一种可再生能源。当盐和淡水混合时释放的吉布斯自由能可以在一个叫做反向电渗析（RED）的过程中被捕获。本研究调查了 RED 中膜间距离和给水流率的影响，以将功率密度输出提高一倍。通过使用间隔物施加膜间距离，实验研究了 60、100、200 和 485 μm 的膜间距离。较小的膜间距离产生更大的（总）功率密度（即每膜面积产生的功率）。实现了 2.2 W/m(2)的最大值，几乎是之前工作中报道的最大功率密度的两倍。此外，较小的膜间距离具有更高的能量效率。新的改进需要集中在使用无间隔设计来降低通过 RED 设备泵送给水泵所需的压降。在这种情况下，可以在较小的膜间距离下，每平方米膜面积的输出功率超过 4 W。
