ProVision Solar: Hunter Residence
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In the fall of 2012, Power-One teamed up with ProVision Solar to beta test the new Power-One Aurora MICRO system. ProVision Solar had an ideal candidate: a retired US Navy lieutenant commander who was eager to be the first in his state to have Power-One microinverters installed at his residence. The beta site is located in a coastal environment on Hawaii’s Big Island.
The 32-module array is split across two roof surfaces, one facing east and one west. The array is mounted flush to the corrugated metal roofing with stainless steel headless hanger bolts that are fastened to the roof system’s purlins. Up to 15 Aurora microinverters can be wired in parallel per branch circuit. Power-One’s ac trunk cables are installed along the racking system, and drop cables connect the microinverters to one of three ac branch circuits. Homerun wiring was laid in PVC conduit due to the site’s corrosive coastal environment.
One challenge with this beta installation was integrating Power-One’s Conversion Data Device (CDD) datalogger with the system. The CDD can support data input from a maximum of 30 modules, which meant the system required two units. One major benefit of the Power-One microinverter system is that data communication between the microinverters and the datalogger is wireless. However, the site’s metal roof interfered with communications. Relocating the CDD’s antenna closer to the array increased the signal strength between the micros and the datalogger and solved the issue. During beta testing, ProVision worked with Power-One to make improvements to the monitoring system’s graphical display.
“We are very excited to be leading the charge here in the Aloha State with Power-One micros. We have installed seven additional Aurora MICRO systems to date.”
—Marco Mangelsdorf, ProVision Solar
DESIGNER: Marco Mangelsdorf, president, ProVision Solar, provision-solar.com
LEAD INSTALLER: Matt Kleinfelder, crew chief, ProVision Solar
DATE COMMISSIONED: November 2012
INSTALLATION TIME FRAME: 4 days
LOCATION: Hilo, HI, 19°N
SOLAR RESOURCE: 4.8 kWh/m2/day
HIGH/LOW DESIGN TEMPERATURES: per Solar ABCs solar reference map: 84°F/59°F
ARRAY CAPACITY: 7.8 kWdc
ANNUAL AC PRODUCTION: 9,490 kWh
MODULES: 32 SunPower SPR-245NE-WHT-D, 245 W, +5/-3%, 6.05 Imp, 40.5 Vmp, 6.43 Isc, 48.8 Voc
INVERTERS: Single-phase, 240 Vac service; 32 Power-One Aurora MICRO-0.25-I-OUTD-US-208/240, 250 W, 65 Vdc maximum input, 25–60 Vdc full power MPPT range, 15 inverters per ac branch circuit maximum
ARRAY: One microinverter per module, three ac branch circuits, 7.8 kWdc total
ARRAY INSTALLATION: Metal corrugated roofing, flush mount, Professional Solar Products racking; 18 modules at 90° azimuth, 10° tilt; 14 modules at 270° azimuth, 10° tilt
SYSTEM MONITORING: Power-One Aurora Vision wireless data monitoring with EasyView web portal