Waste heat recycling from phosphoric acid fuel cells for desalination with hydrophilic modified tubular stills: Performance prediction and regulation

Phosphoric acid fuel cells are a promising technology for clean energy generation; however, a significant portion of the fuel's chemical energy is transformed into waste heat, reducing overall efficiency and potentially affecting long-term durability. This study aims to address these limitations by integrating a hydrophilic modified tubular still to recycle waste heat for seawater desalination, forming a novel hybrid system capable of simultaneous electricity generation and freshwater production. To evaluate the effectiveness, the vital evaluation metrics for the hybrid system are analytically derived through the establishment of a mathematical framework. The hybrid system achieves significant improvements over a standalone system, with enhancements reaching up to 22.86 % in power density, 12.18 % in exergetic efficiency, and 12.63 % in energetic efficiency. A comprehensive parametric analysis reveals that increasing the exchange current density, operation temperature, environment temperature, and charge transfer coefficient, while reducing phosphoric acid concentration, tubular shell diameter, wind velocity, and electrolyte thickness, positively impact the hybrid system's performance. Local sensitivity analysis pinpoints electrolyte thickness as the most sensitive parameter affecting performance, while environment temperature has the least sensitivity. These results offer insightful guidance for designing and running such a high-performance hybrid system, with the potential to enhance both efficiency and operational longevity.