Life cycle assessment of passive radiative cooling materials

Abstract

Passive cooling has been a subject of research interest for decades, due to its ability to provide low-cost heat rejection. Recently, the science of passive radiative cooling materials has shown rapid progress, with the synthesis of raw materials that exhibit lower-than-ambient temperature even under direct sunlight, which however requires the use of pigments at very high-volume fractions. As the development of these materials is still in the research stage, it is important to have a deeper understanding of their environmental impact. For this purpose, in this study, a life cycle assessment is performed on different compositions of materials that have shown the potential for passive cooling under full sunshine with high emissivity and reflectance The compositions studied are based on calcium carbonate, barium sulphate, P(VDF-HPF) and P(FA) polymers, with a life cycle assessment focused on the production of these materials. The results indicate that polymer-based material shows the highest environmental impact due to the use of PFA. In the meantime, the lower footprint is found for the calcium carbonate used as the base and water and ethanol as solvents. Overall, for the future fabrication of passive radiative cooling materials, it is suggested to use materials that do not require extensive processing and are abundant. Finally, organic solvents should be replaced by more environmentally friendly substances.