This site from the National Renewable Energy Laboratory's (NREL's) High Performance Building Research division showcases recent improvements in energy efficiency of high-use structures in southern Utah's National Parks. The Zion National Park Visitor Center, one of the Park Service's most efficient complexes, is furnished with Trombe walls for passive solar heating, a passive downdraft cooltower, a roof-mounted photovoltaic (PV) system, and more.