The Zion National Park Visitor Center and Comfort Station is one of the National Park Service's most efficient complexes.

Visitor Center and Comfort Station

Features included in the design of the 7,600-ft² (706-m²) Visitor Center and 1,100-ft² (102-m²) Comfort Station are daylighting, trombe walls for passive solar heating, downdraft cooltowers for natural ventilation cooling, energy-efficient lighting, and advanced building controls.

It is estimated that these design features result in about 10 kW of electrical demand savings.

Project Description

A roof-mounted photovoltaic (PV) system provides electrical power. The PV system reduces the amount of power purchased from the utility and it supplies backup power when grid power is not available. The photovoltaic system is grid-tied so electricity generated by the solar array in excess of the visitor center's needs will be fed into the utility grid.

Cooltowers at the Visitor Center help bring the temperature down.

A power panel contains the inverters and other balance-of -system components of the PV system. The inverters convert the direct current from the PV array and batteries to alternating current. Alternating current is necessary for powering the visitor center and for feeding into the utility grid.

The trombe wall is shaded by the roof overhang in the summer to reduce the heat load on the building. In the winter, the sun is at a lower angle and heats the wall which is behind a layer of glass. The heat is slowly released into the building, reducing the run-time of the conventional heating system.

When natural ventilation is not enough, cooltowers at the Zion National Park Visitor Center help bring the temperature down. Water is pumped over pads located at the top of the tower. This water evaporates, cooling the air. The cool, dense air "falls" through the tower and exits through the large openings at the base of the tower.

The energy management computer controls these openings and can direct cool air into the building or out onto the patio. The only energy required for the towers is a fractional horsepower pump used to circulate water over the pads. No fans are needed. Measured flows from the tower are approximately 8000 cubic feet per minute for each tower.

An off-grid photovoltaic system used at a back-country ranger cabin.	Two inverters (on left) convert the direct current from the photovoltaic array and batteries to alternating current.

The park utilizes off-grid photovoltaic systems at two back-country ranger cabins. These trailer mounted systems power lights, a pump to pressurize the water system, and electronic equipment such as stereos and laptop computers. The PV systems are removed in the winter off-season to protect them from theft and vandalism.

Participation of the Utah State Energy Program in this project was limited to $7,000 funding for the PV system.