Figure 1: Pearl River Tower, Guangzhou, China, is a 984 ft (300 m) commercial tower with a net-zero energy design goal. It has mechanically ventilated double skin façades; underfloor air distribution; overhead radiant cooling; wind and solar renewable energy; and more. Ventilating Façades 16 ASHRAE Journal ashrae.org April 2009 Images Courtesy of Skidmore Owings and Merrill LLP Chicago ,