SUMMARY
UCLA researchers in the Department of Materials Science & Engineering have developed coatings with exceptional solar-ultraviolet (UV) reflectance for efficient passive daytime radiative cooling of buildings.
BACKGROUND
‘Cool’ white exterior coatings reflect sunlight (0.3-2.5 μm) and radiate heat (4-40 μm, particularly 8-13 μm) into outer space. In doing so, they have a net passive cooling effect and are a sustainable alternative to air-conditioners to cool buildings and outdoor structures. However, the cooling performance of traditional ‘cool’ exterior coatings suffers from material limitations, primarily the absorption of UV light, lowering their cooling efficiency to ~0.85 or lower. New types of exterior coatings are needed to optimize reflectivity > 0.94 and improve cooling performance.
INNOVATION
UCLA researchers in the Department of Materials Science & Engineering have developed an exterior coating with exceptional solar-UV reflectance. The coating can be applied by a painting, dip-coating or other simple techniques. Upon drying, the coating, in sufficient thicknesses, can achieve solar reflectance from 0.94-0.98. With a high overall solar reflectance and high thermal emittance, this coating is ideal for passive daytime radiative cooling of buildings.
PATENT
Systems and Methods for UV-Reflective Paints with High Overall Solar Reflectance for Passive Cooling
POTENTIAL APPLICATIONS
- Passive daytime radiative cooling
- Building exterior
- Cooling data centers
- Cooling air conditioning units
- Automobile and aerospace paints
- Cool roofs
- Cool roof materials
ADVANTAGES
- ~5˚C cooling relative to state-of-the-art white paints under noontime summer sunlight
- High solar reflectance
- High UV reflectance
- Solar reflectance 0.94-0.98
- Simple application
- Painting, spraying, dip-coating
- Weatherproof
- Low-cost
RELATED MATERIALS
DEVELOPMENT TO DATE
Material tested for proof-of-concept. ~5˚C cooling relative to state-of-the art commercial cool paints demonstrated under summertime sunlight.
RELATED ARTICLES
https://www.washingtonpost.com/climate-solutions/2020/10/07/radiative-cooling-climate-change/
OPTICA (OSA) WEBINAR
Radiative Cooling: Optics Enables Access to the Cold of Space for Energy on Earth