The metal panels shown on the west and south faces of the Rapid City (S.D.) Community Center South are a proprietary system known as SolarWall⢠that functions as Trombe envisioned. The air exchange serving the gymnasium (arched windows near the ceiling of the gym are visible) runs through the unit, bringing fresh, outside air through the space behind the panels to be passively heated during the long winter months, much like an air-to-air heat exchanger. Building architect Forefront Design Inc. of Rapid City notes that during the summer, the SolarWall can be bypassed or controlled with a dampering system.