Recent developments in passive daytime radiative cooling for enhancing sustainability in agro-food systems

Passive Daytime Radiative Cooling (PDRC) is an emerging energy-independent cooling strategy that enables sub-ambient temperatures by radiating thermal energy directly into outer space through materials engineered with high solar reflectivity and strong thermal emissivity. This mechanism bypasses the need for electricity or mechanical energy, making it an ideal solution for regions facing energy shortages or seeking sustainable alternatives to conventional cooling. Recent innovations in PDRC materials, including reflective polymer coatings, photonic nanostructures, and hybrid composites have broadened its applicability in sectors such as building design and electronics. However, its integration into agriculture remains limited despite the sector’s urgent need for passive and affordable cooling technologies.

This review critically explores the evolution of PDRC materials and highlights their immense untapped potential in agricultural applications. These include greenhouse cooling, post-harvest storage of perishables, and protective mulches for open-field crops, each of which can benefit significantly from consistent sub-ambient temperature maintenance. It examines the working mechanisms, material properties, and performance evaluations of various PDRC technologies and their suitability for agricultural systems, discusses challenges related to scalability, durability, cost-effectiveness, and field deployment. It offers a critical synthesis of current advancements and challenges in PDRC materials, aiming to guide their effective integration into smart agriculture.