Vanadium pentoxide-coated smart windows for passive radiative cooling applications

Passive radiative cooling (PRC)-based smart windows are emerging as a potential solution for reducing the energy needs of buildings, both homes and offices alike. While a lot of research has occurred in this regard, vanadium oxide-based materials are studied very recently. We carry out a finite element method-based simulation study to understand the behavior of using vanadium pentoxide (V2O5) as a coating on glass windows. The proposed design can help in saving energy by emitting cooler rays inside the building when direct sun rays fall on the coated glass surface, thereby reducing internal room temperatures. It is also a solution to global warming, as the emissions from ACs will reduce due to the lower inside temperature of buildings thereby reducing demand on power usage. We found that the ambient temperature (Tamb) inside buildings can be reduced by up to 8°C when the outer temperature is 40°C. Also, the surface radiosity of V2O5 windows is twice that of glass windows and increases with the outer temperature. Lastly, we compare the performance of V2O5 with that of VO2 and find that they have similar characteristics of radiant exitance, surface radiosity and surface emissivity of long-wave infrared (LWIR) rays thus making V2O5 as a possible candidate for PRC which is low cost and affordable to many people.