Nanomaterials enable dual-mode heating and cooling device

Engineers at Duke University have demonstrated a dual-mode heating and cooling device for building climate control that, if widely deployed in the U.S., could cut HVAC energy use by nearly 20 percent. The invention uses a combination of mechanics and nanomaterials to either harness or expel certain wavelengths of light. Depending on conditions, rollers move a sheet back and forth to expose either heat-trapping materials or cooling materials.