Topic hub·Emitting heat to space

Radiative Cooling & PDRC

Passive daytime radiative cooling — how carefully engineered surfaces can be several degrees cooler than the surrounding air, even in direct sunlight.

Atmospheric transparency window: 8-13 µm
Effective sky temperature: ~3 K
Solar reflectance in best PDRC materials: >95%

Topics

Passive Cooling Heat Resilience Urban Heat Radiative Cooling & PDRC Albedo & Reflectivity Climate Science Water & Cooling Agriculture & Cooling Measurement & Data Climate Adaptation Communities & Stories

The physics

Materials & engineering

Deployment

Key terms in this topic

Radiative Cooling
Heat loss from any object by emitting thermal infrared radiation.
Passive Daytime Radiative CoolingPDRC
A material that stays cooler than the air even under direct sunlight by radiating heat to the cold sky.
Atmospheric WindowSky Window
A range of infrared wavelengths (roughly 8–13 μm) where the atmosphere absorbs relatively little of Earth's outgoing thermal radiation.
Thermal Emittance
How efficiently a surface releases heat as infrared radiation.
Solar Reflectance
The fraction of incoming solar energy a surface reflects across the sun's spectrum.
Reflective Cooling
Cooling by bouncing sunlight away from a surface before it can be absorbed as heat.
Passive Cooling
Cooling a surface, building or space using materials and design instead of electricity.
Surface Energy Balance
The bookkeeping of energy flowing into and out of a surface at every moment.

Full glossary

Radiative Cooling & PDRC

The physics

Radiative cooling

Surface reflection

Earth's energy balance

Greenhouse effect

Materials & engineering

Materials research

Our technologies

Measurement

Deployment

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