Research Lab for Advanced Separation Processes, Department of Chemical Engineering, Iran University of Science and Technology, Narmak, Tehran 16846-13114, Iran.
Microfluidics and Microscale Transport Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Assam 781039, India.
Phys Chem Chem Phys. 2022 Aug 31;24(34):20303-20317. doi: 10.1039/d2cp01015a.
Salinity energy generation (SEG) studies have only been done under isothermal conditions at ambient temperature. The production of salinity energy can be improved under non-isothermal conditions, albeit preserving the energy efficiency. In the current study, the effects of gradients of temperature and concentration on the salinity energy generation process were examined simultaneously. Based on the temperature-dependent properties resulting from both temperature and concentration gradients, a numerical study was carried out to determine the maximum efficiency of salinity energy generation in funnel-shaped soft nanochannels. It was presumed that a dense layer of negative charge, called a polyelectrolyte layer (PEL), is coated on the walls of the nanochannels. Co-current and counter-current modes were used to obtain temperature and concentration gradients. Under steady-state conditions, the Poisson-Nernst-Planck, Stokes-Brinkman, and energy equations were numerically solved using equivalent approaches. The results revealed that by increasing the temperature and concentration ratios in both co-current and counter-current modes of operation, the salinity energy generation increased appreciably. The salinity energy generation increased from 30 to 80 pW upon increasing the temperature ratio from 1 to 8 at a constant concentration ratio of 1000 in counter-current mode. As verified from this analysis, low-grade heat sources (<100 °C) provide considerable energy conversion in PEL grafted nanofluidic confinement when placed between electrolyte solutions of different temperatures.
盐差能发电（SEG）的研究仅在环境温度下的等温条件下进行。在非等温条件下可以提高盐差能的产量，尽管会保持能量效率。在当前的研究中，同时考察了温度和浓度梯度对盐差能发电过程的影响。基于温度和浓度梯度产生的依赖于温度的特性，进行了数值研究以确定在漏斗形软纳滤通道中盐差能发电的最大效率。假设在纳滤通道的壁上涂覆了一层致密的带负电荷的层，称为聚电解质层（PEL）。使用同向流和反向流模式来获得温度和浓度梯度。在稳态条件下，使用等效方法数值求解泊松-纳维-斯特拉斯方程、斯托克斯-布林克曼方程和能量方程。结果表明，通过在同向流和反向流两种操作模式下增加温度和浓度比，可以显著提高盐差能的产生。在反向流模式下，当温度比从 1 增加到 8 时，浓度比保持在 1000 不变，盐差能的产生从 30 增加到 80 pW。从这项分析中可以验证，当将不同温度的电解质溶液置于其间时，低品位热源（<100°C）在接枝有 PEL 的纳米流体限制中提供了可观的能量转换。
