Frey Electric: Harvest Hill Golf Course
Inside this Article
In December 2012, LightWave Solar commissioned a ground-mounted PV system at the University School...
One of the preliminary design goals for the BRC Group of Companies’ installation was a target array...
Special Transit is a nonprofit organization in Boulder County, Colorado, that provides...
The Harvest Hill Golf Course underwent extensive renovations that were completed in May 2013, including the construction of a new clubhouse, two cart houses and a tournament pavilion. To help reduce facility operations costs, Frey Electric installed a 37.44 kW PV array on the two new cart houses. The array is expected to offset 20% of Harvest Hill’s annual energy consumption. While the PV system was not part of the project’s initial design, the arrays were relatively easy to integrate with the cart house buildings.
The 144-module array is split across two 12:12 metal standing-seam roofs with azimuths of 240° and 259°. The installers flush-mounted the array with S-5! Mini Clamps and PV Kits, so roof penetrations were not necessary. The steep roof angle presented both challenges and a performance advantage. The crew needed to use a two-person basket lift during the array installation. They pre-assembled S-5! Kits in the shop to reduce field labor and minimize the potential loss of hardware off the roof during installation. At the jobsite, the installers quickly positioned the assemblies, installed and torqued them per specification. The steep roofs offer a performance benefit as the arrays shed snow easily during the winter months, which increases overall energy production.
Each roof has sufficient area for the installation of 72 modules. The corresponding array layouts are well matched for integration with four 10 kW Fronius IG Plus Advanced inverters. The designers initially considered microinverters; however, due to the steep roof pitch and difficult access, they chose string inverters to eliminate the need to access the roof in the event of an inverter failure.
The crew installed Wiley ACE 3-pole transition boxes on each roof to make the transition from PV Wire to THHN conductors. They connected three individual PV source circuits to each Fronius IG Plus Advanced inverter via its integrated fused combiner. Inside each cart house, the ac output of two inverters is combined in a load center and then connected to a dedicated PV generation meter. The combined output from one cart house runs underground to the other cart house. A third load center combines the output of all four inverters. A fusible disconnect protects this single circuit, which terminates on the load side of a 150 kVA 480/208 service distribution transformer. This was the most economical point of connection, since the existing 208 V panels are located in other buildings.
The crew installed a Fronius Datalogger Web unit and tested it using a WLAN Wi-Fi stick antenna. However, the metal building surrounding the WLAN stick prevented the inverters from receiving an adequate signal. The installers then swapped out the antenna with a Fronius External Antenna LAN stick mounted on the outside of the building and connected to the Datalogger Web using a USB extension cable approximately 80 feet long. Excessive power loss over the USB cable prevented this second configuration from working. Ultimately, the crew moved the Datalogger Web closer to the external antenna and ran a Cat 5 cable to the first inverter.
“Initially, working from lifts added a level of difficulty for the installation crew, but the final product came out well. While the array orientations are not ideal, energy production has been above the projected values.”
—Deborah Zarbo, Frey Electric
DESIGNER: Deborah Zarbo, engineer, Frey Electric, frey-electric.com
LEAD INSTALLER: Ray Szopinski, electric site foreman, Frey Electric
DATE COMMISSIONED: July 2013
INSTALLATION TIME FRAME: 18 days
LOCATION: Orchard Park, NY, 43°N
SOLAR RESOURCE: 4.2 kWh/m2/day
ASHRAE DESIGN TEMPERATURES: 86°F 2% average high, −4°F extreme minimum
ARRAY CAPACITY: 37.44 kWdc
ANNUAL AC PRODUCTION: 36,262 kWh
MODULES: 144 Helios Solar Works 6T 260, 260 W STC, +3/-0%, 8.46 Imp, 30.84 Vmp, 8.9 Isc, 37.73 Voc
INVERTERS: 3-phase 120/208 Vac service, four Fronius IG Plus Advanced 10.0-3 UNI Delta, 10 kW, 600 Vdc maximum input, 230–500 Vdc MPPT range
ARRAY: 12 modules per source circuit (3,120 W, 8.46 Imp, 370.1 Vmp, 8.9 Isc, 452.8 Voc), three source circuits per inverter (9,360 W, 25.4 Imp, 370.1 Vmp, 26.7 Isc, 452.8 Voc), 37.44 kW array total
ARRAY INSTALLATION: Roof mount, standing-seam metal roofing, S-5! Mini Clamps with S-5! PV Kits; 72 modules with 240° azimuth, 72 modules with 259° azimuth, 45° tilt
ARRAY SOURCE-CIRCUIT COMBINERS: Inverter integrated, 15 A fuses
SYSTEM MONITORING: Fronius Datalogger Web with external LAN antenna