Kenyon Energy: Darden Restaurant Headquarters

The 1.1 MW Darden restaurant headquarters system is currently the largest privately owned PV installation in Florida. The array is composed of a custom galvanized steel solar canopy mounted over an existing parking garage, and a ballasted roof-mounted system installed on the Darden restaurant support center building. Combined, a total of 4,404 SolarWorld 250 W modules are deployed across these two arrays. Several factors played a role in making this a complex project from the conceptual design phase through system commissioning.

The most unique feature is the solar canopy structure that was built on top of the four-story, 85,000-squarefoot parking garage, which is located in Florida’s 120-mph wind zone. This canopy structure also supports vertically mounted solar modules in landscape format on the east-, south- and westfacing portions of the structure. These vertically mounted modules serve as an architectural facade that shields the canopy’s supporting galvanized steel trusses and girders when Darden’s employees and campus visitors view the structure from ground level.

Optimizing the rooftop PV system’s power performance ratio while keeping the total roof dead load below 5.5 pounds per square foot, and keeping a roof membrane penetration-free in a high wind zone was a complex challenge to manage. Various racking solutions were considered, but ultimately DPW Solar’s POWER-FAB CRS solution was selected. The CRS racking system secured the solar modules at an optimal 15° tilt angle. The array was laid out parallel to the building’s south edge, which has an azimuth of 147°. This approach allowed for a greater module-to-roof density ratio and provided an aesthetically pleasing installation while optimizing the system’s annual performance.

“During the installation of the roofmounted system, we encountered significant inconsistencies with the flatness of the roof surface, primarily at areas adjacent to roof drains. Our installation team worked with the racking manufacturer, DPW Solar, to quickly create a solution, which was to relocate the modules from the affected areas to alternate roof locations. The balance of the modules located on less severe slopes was accommodated with custom-designed EPDM-protected bases.”

Andreas Zahariadis, Kenyon Energy

“As is fairly common in the industry, for our client to qualify for the Federal ITC grant, we were tasked with getting the project designed, installed and commissioned by December 31, 2011. We made the commitment to our client to meet this critical deadline, and with the dedication and hard work of the entire project team, we completed installation of the 1.1 MW project on December 22—in 90 days!”

Tim Bonczek, senior VP of construction, Kenyon Energy

Overview

EPC CONTRACTOR: Andreas Zahariadis, VP of construction, Kenyon Energy, kenyonenergy.com
ELECTRICAL CONTRACTOR: Tri-City Electrical Contractors, tcelectric.com
DATE COMMISSIONED: December 22, 2011
INSTALLATION TIME FRAME: 90 days
LOCATION: Orlando, FL, 28.5°N
SOLAR RESOURCE: 4.4 kWh/m2/day
HIGH/LOW DESIGN TEMPERATURES: per Solar ABCs solar reference map: 93°F/30°F ARRAY CAPACITY: 1.1 MW
ANNUAL AC PRODUCTION: 1,600 MWh

Equipment Specifications

MODULES: 4,404 SolarWorld Sunmodule SW 250 mono, Version 2.0 frame, 250 W STC, +5/-0 W, 8.05 Imp, 31.1 Vmp, 8.28 Isc, 37.8 Voc
INVERTERS: 3-phase, 480 Vac service, four Advanced Energy PVP260kW, 260 kW, 600 Vdc maximum input, 295–595 Vdc MPPT range, 3-phase, 480Y Vac output; six SMA Sunny Boy 5000- US, 5 kW, 600 Vdc maximum input, 250–480 Vdc MPPT range, singlephase, 277 Vac output
CANOPY ARRAY: 3,192 modules, three PVP260kW inverters, 14 modules per source circuit (3,500 W, 8.05 Imp, 435.4 Vmp, 8.28 Isc, 529.2 Voc); inverters 1 and 2: 78 source circuits each (273 kW, 627.9 Imp, 435.4 Vmp, 645.8 Isc, 529.2 Voc); inverter 3: 72 source circuits (252 kW, 579.6 Imp, 435.4 Vmp, 596.2 Isc, 529.2 Voc); 798 kW array total
CANOPY ARRAY INSTALLATION: Custom galvanized steel truss and girder mounting structure, 180° azimuth, 10° tilt
ROOFTOP ARRAY: 1,078 modules, one PVP260kW inverter, 14 modules per source circuit (3,500 W, 8.05 Imp, 435.4 Vmp, 8.28 Isc, 529.2 Voc); inverter 4: 77 source circuits (269.5 kW, 619.9 Imp, 435.4 Vmp, 637.6 Isc, 529.2 Voc); 269.5 kW array total
ROOFTOP ARRAY INSTALLATION: TPO roofing, ballast-only DPW Solar POWER-FAB CRS racking, 147° azimuth, 15° tilt
VERTICAL ARRAY: 134 modules, six SMA Sunny Boy 5000-US inverters, 10–13 modules per source circuit, two source circuits per inverter, 33.5 kW array total
VERTICAL ARRAY INSTALLATION: Unirac SunFrame racking mounted to custom steel canopy structure, 40 modules with 90° azimuth, 52 modules with 180° azimuth, 42 modules with 270° azimuth; 90° tilt
ARRAY COMBINERS: SolarBOS Disconnect Combiners, 15 A fuses
SYSTEM MONITORING: DECK Monitoring tracks inverter-direct output data and provides revenue-grade production metering for each 260 kW inverter and the electrical combination panel of the six 5 kW SMA inverters. Environmental monitoring includes ambient temperature, cell temperature, irradiance, humidity, barometric pressure, and wind speed and direction

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