The osmotic heat engine (OHE) stands out as a promising approach for converting ultralow-grade heat into electricity, owing to its scalability and non-discharge attributes. However, challenges arise from the substantial latent heat consumption or the restricted concentration difference during the regeneration stage, constraining improvements in energy efficiency and power density. Here, we introduce an isotonic separation process to a thermal-responsive ionic liquids (TRILs) based OHE system, where the water-rich phase of TRILs after phase transition is further filtrated into pure water and another part of TRILs-rich phase with constant osmotic pressure. This process amplifies the net energy of mixing in the mixing process. Ultimately, a state-of-the-art Carnot-relative efficiency of 48% is achieved within a temperature difference of 25-40 °C, where the hot side is maintained at 60 °C. Additionally, employing a forward osmosis device yields an exemplary peak power density of 10.9 W m.

中文翻译：

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等渗分离可利用热响应离子液体实现高效的低级热转换

渗透热机（OHE）因其可扩展性和无排放特性而成为将超低品位热量转化为电能的一种有前途的方法。然而，再生阶段大量的潜热消耗或有限的浓度差带来了挑战，限制了能源效率和功率密度的提高。在这里，我们将等渗分离过程引入基于热响应离子液体（TRILs）的OHE系统，其中相变后的TRILs富水相进一步过滤成纯水和另一部分具有恒定渗透压的TRILs富集相压力。该过程放大了混合过程中的混合净能量。最终，在 25-40 °C 的温差内实现了 48% 的最先进的卡诺相对效率，其中热侧保持在 60 °C。另外，采用正向渗透装置产生10.9W m 的示例性峰值功率密度。