Advanced thermal strategies in pool boiling: Surface structuring, nanofluids, and eco-efficient integration

Pool boiling is a promising heat transfer mechanism capable of handling higher heat fluxes. Further augmentation in heat transfer coefficients and the critical heat flux was one of the major topic of research. Over time, the researchers have prioritized to environmental considerations and sustainability due to increasing emphasis on energy efficiency and eco-friendly thermal management systems. The present article provides a critical analysis of major enhancement techniques, namely, the use of nano fluids, surfactants and characterized surfaces, and then evaluates their potential to augment the heat transfer performance. The results reported in the literature were discussed in the context of the type of enhancement technique used and the system configuration. The underlying physics, such as nanoparticle-induced vapour bubble nucleation enhancement, modification of surface tension near the critical micelle concentration (CMC) and capillary wicking of liquid over micro- and nano-structured surfaces, are discussed in detail. An estimate of energy payback period along with life-cycle evaluation and the practical implementation challenges, is introduced. Rejecting the superiority hypothesis of any one technique under all conditions, the review advocates the selection process of an improvement technique which can balance thermal performance, stability, manufacturability and sustainability. Future work should consider combining enhancement techniques with standardized life cycle metrics to enable thermal system design towards sustainable thermal systems.