Passive technology on roofs and facades could greatly reduce HVAC energy consumption. Engineers have developed smart material technology that, with the flip of a switch, can alternate between harvesting heat from sunlight and allowing an object to cool. The window-like device has no moving parts and could be a boon for HVAC savings, potentially cutting energy usage by nearly 20% in the United States alone.
As anyone who has ever parked a car in the sun on a hot summer day knows, glass windows are great at letting sunlight in but terrible at allowing heat out.
