The modular design of the supporting structure, photovoltaic
(PV) module racking and the electrical equipment at Tucson International Airport allowed for simplified fabrication and reduced onsite construction time. Phase 1 of the project covers approximately 3 acres covering parking aisles and was completed in October 2013.
The structure supporting the PV system was fabricated from steel structural components and painted with a durable, low-maintenance coating with a color scheme designated by the airport to be consistent with the existing airport color scheme.
The project utilizes 488 tons of gray painted W18 by 97 and W18 by 108 Superstructure beams, 117 tons of gray painted HSS 16-inch-diameter by 5/8-inch Superstructure direct burial columns, 450 LF of 18-inch high flat gray painted 20-gauge, concealed fastened flat panel facia siding at perimeter beams. It has a Schletter-supplied S-4 purlins, mill finish aluminum and fastening system that provide solar panel support.
Constructed of steel and metal components, the structural system provides design and construction flexibility allowing adjustments to accommodate varying field conditions of the existing parking lot.
The airport PV System is comprised of 51 individual PV arrays arranged to follow the curvature of the existing parking lot rows on radial lines centered on the pedestrian entrance to the airport terminal. Each array contains 98 individual Kyocera PV modules arranged in seven strings of 14 PV modules mounted on a steel supporting structure. A fixed tilt of 10 degrees of the PV arrays is incorporated into the design of the supporting structure. The PV system has been designed to provide 1.0 MW-AC at PVUSA Test Conditions with a maximum annual degradation of no more than 0.5 percent.
The radial layout of the PV arrays creates positive and negative space when viewed from either above, in flight, or below, at the pedestrian level. At ground level this layout creates a pattern of shade and shadow that softens the visual impact of the structural support system.
Structural columns were designed to have a minimum cross-sectional area and were located to minimize interference with existing parking and traffic flow.
The orientation of the PV arrays was determined via a Federal Aviation Administration (FAA)-required glare analysis for glare and glint modeling of the PV arrays to aircraft and the air traffic control tower.
The structural system design was based upon providing the airport with a PV system that is flexible and durable enough to minimize disturbance to the parking lot during construction and minimize the permanent loss of parking spaces. The structure is tall enough to allow higher profile vehicles to drive through the parking lot without obstruction.
The PV system has an architectural style incorporating elements of the established architectural themes at the airport. Electrical conduit is placed within the columns and beam flanges of the supporting structure to conceal from view. Vegetated green walls of steel soften the appearance of exterior vertical columns.
Parking lot lighting and signage are integral to the supporting array structure. The inverter yard is concealed on four sides by additional vegetated green wall of steel. This is intended to soften the presence of the yard in the parking lot, while allowing air movement through the inverter yard.
Some decorative trees were removed to eliminate reductions in solar power generation from shading of the PV arrays. Landscape design utilizes heat- and drought-resistant xeriscape plantings that are consistent with the landscape architecture of the terminal. Shaded landscape areas will receive shade-tolerant plantings.
The structural components have been designed for a minimum 20-year life, the PV modules have been designed for a minimum 20-year life and the inverters will be designed for a minimum 10-year life. The structure and PV modules meet the FAA’s Airport Improvement Program, Buy America Preferences. Photography courtesy of Tucson Airport Authority.
Owner: Tucson Airport Authority, Tucson
General contractor: Barker-Morrissey Contracting, Tucson
Architect: deTodo Architecture, Phoenix
Developer: Natural Power and Energy, Scottsdale, Ariz.
Structural engineer: Schneider Structural Engineering, Tucson
Electrical engineer: MW Engineering, Tempe, Ariz.
Electrical contractor: Delta Diversified, Tempe
Photovoltaics: Kyocera Solar Inc., Scottsdale, www.kyocerasolar.com
Inverters: Advanced Energy, Fort Collins, Colo., www.advanced-energy.com
Beams, direct burial columns, panel siding: Parsons Steel, Tucson, www.parsonsbuilders.com
Purlins, fastening system: Schletter Inc., Tucson, www.schletter.us