Ocean thermocline energy is a sustainable and reliable heat source for seawater desalination in remote islands that has no access to primary energy. To adapt to the unique features of thermocline energy, i.e., a sensible heat source with a small temperature gradient, we propose a novel desalination system combining the direct-spray technology and multi-effect distillation (MED). The steam generator of a conventional MED is replaced by a tubeless spray evaporator, which eliminates the thermal resistance across the heat transfer surface. The merits of this system, which is named spray-assisted multi-effect distillation (SMED), include reduced internal losses, higher productivity, and smaller heat transfer areas. To quantify the potential of the thermocline-driven SMED system, we firstly conducted a thermodynamic analysis. Comparing with MED, SMED boosts freshwater productivity by 35%, while the pumping power consumption and required heat transfer area are reduced by 58% and 17%, respectively. Based on the thermodynamic performances, the economic potential of SMED is assessed. The SMED system demonstrates significant economic benefits due to the reduced heat transfer area and higher productivity. The optimal cost of freshwater is $1.53/m³, 55% lower than MED under the same operating conditions. The originality and novelty of this study can be summarized as follows: (a) a novel desalination system that maximizes thermocline energy utilization is proposed; (b) a detailed process model is developed and validated for system design and optimization; and (c) a thermo-economic analysis is conducted to maximize the desalination performance. The derived results highlight the thermodynamic and economic potentials of the proposed SMED system, making it a competitive and appealing solution for thermocline desalination.

海洋温跃层能源是无法获得一次能源的偏远岛屿海水淡化的可持续且可靠的热源。为了适应温跃层能源的独特特性，即具有小温度梯度的显热源，我们提出了一种结合直接喷雾技术和多效蒸馏（MED）的新型海水淡化系统。传统 MED 的蒸汽发生器被无管喷雾蒸发器取代，从而消除了传热表面的热阻。该系统被称为喷雾辅助多效蒸馏 (SMED)，其优点包括减少内部损失、提高生产率和较小的传热面积。为了量化温跃层驱动的 SMED 系统的潜力，我们首先进行了热力学分析。与MED相比，SMED 将淡水生产率提高了 35%，而泵送功率消耗和所需的传热面积分别减少了 58% 和 17%。基于热力学性能，评估了 SMED 的经济潜力。由于传热面积减少和生产率提高，SMED 系统显示出显着的经济效益。淡水的最佳成本为 $1.53/m³、同等操作条件下比MED低55%。本研究的独创性和新颖性可以概括如下： (a) 提出了一种能够最大限度地利用温跃层能量的新型海水淡化系统；(b) 为系统设计和优化开发和验证详细的过程模型；(c) 进行热经济分析以最大限度地提高脱盐性能。得出的结果突出了所提议的 SMED 系统的热力学和经济潜力，使其成为具有竞争力和吸引力的温跃层脱盐解决方案。