Jeff Spies, the senior director of business development at Quick Mount PV, contracted American Solar to install a PV system at his residence. The system employs one of the first SMA 4000TL-US inverters installed in the US. This non-isolated inverter features two MPP trackers and a Secure Power Supply function that provides up to 12 amps of backup power at 120 Vac, given that there is sufficient solar irradiance

American Solar’s licensed roofing contractor division refurbished the 16-year-old roof and relocated plumbing and gas vent stacks to create space for the array. The SMA 4000TL-US’s dual MPP channels and wide operating MPPT range made it possible to locate a 3,120 W array on a southeast-facing roof and a 1,560 W array on the southwest-facing garage roof.

To ensure that the home’s tile roof would last the 30-year life of the array, American Solar installed a 90# mineral-surface rolled roofing underlayment. Tru-Flow drain-through battens speed rainwater drainage, which extends underlayment life. Ventilation upgrades include Boral vented eave risers and O’Hagin roof vents. The crew used Quick Mount PV’s Quick Hook flashed tile mounts in conjunction with IronRidge Standard mounting rail, providing for an attractive finished appearance. (For details on similar installations, see “Tile Roof Applications,” SolarPro magazine, October/November 2013.)

“Since I work for the leading manufacturer of code-compliant flashed PV mounts, I understand the long-term cost benefits of installing a new roof under the array. When choosing an installer, I looked no further than American Solar. The company did a great job installing a system that offers excellent performance.”

—Jeff Spies, Quick Mount PV

Overview

DESIGNER: Paul Swanson, American Solar, americanpv.com

LEAD INSTALLER: Robert Hileman, American Solar

DATE COMMISSIONED: July 26, 2013

INSTALLATION TIME FRAME: 3 days

LOCATION: Chandler, AZ, 33.3°N

SOLAR RESOURCE: 6.5 kWh/m2/day

ASHRAE DESIGN TEMPERATURES: 109°F 2% average high, 34° extreme minimum

ARRAY CAPACITY: 4.68 kWdc

ANNUAL AC PRODUCTION: 7,500 kWh (projected)

Equipment Specifications

MODULES: 18 LG Electronics LG260S1C-G3, 260 W STC, +3/-0%, 8.61 Imp, 30.2 Vmp, 9.2 Isc, 37.9 Voc

INVERTER: Single-phase 120/240 Vac service, one SMA Sunny Boy 4000TL-US with Secure Power Supply, 4 kW, 600 Vdc maximum input, two MPP trackers, 175–480 Vdc rated MPPT range, 125–500 Vdc operating MPPT range

ARRAY: Two orientations. SW array: one six-module source circuit (1,560 W, 8.61 Imp, 181.2 Vmp, 9.2 Isc, 227.4 Voc); SE array: one 12-module source circuit (3,120 W, 8.61 Imp, 362.4 Vmp, 9.2 Isc, 454.8 Voc); 4.68 kWdc array total

ARRAY INSTALLATION: Monier S-Tiles installed on Tru-Flow drain-through battens, 90# mineral-surface rolled roofing underlayment, Quick Mount PV Quick Hook flashed tile mounts, IronRidge Standard rail; SW array: 223°azimuth, 18° tilt; SE array: 133° azimuth, 18° tilt

SYSTEM MONITORING: SMA Sunny Webbox, SMA Sunny Portal web interface