Nighttime radiative cooling

August 2015

Stanford's Global Climate and Energy Project (GCEP) has awarded Professor Shanui Fan's group funding to develop new techniques for cooling buildings.

Fan reported the energy-saving breakthrough in the journal Nature. Using a thermal photonic approach, the material reflects sunlight and emits heat, demonstrating new possibilities for energy efficiency. The photonic radiative cooler consists of seven alternating layers of hafnium dioxide (HfO2) and silicon dioxide (SiO2) of varying thicknesses, on top of 200 nm of silver (Ag), which are all deposited on top of a 200-mm silicon wafer.

This passive energy source, which exploits the large temperature difference between space and Earth, could provide nighttime lighting without batteries or other electrical inputs.

GCEP is an industry partnership that supports innovative research on energy technologies to address the challenge of global climate change by reducing greenhouse gas emissions. The project includes five corporate sponsors: ExxonMobil, GE, Schlumberger, DuPont and Bank of America.

 

View full Stanford Report article.