Sun Solar: Buzz’s Market

Sun Solar is an integrator with operations and service regions in Missouri, Kansas and South Carolina. In September 2016, it commissioned a 93.28 kWdc system for Buzz’s Market, a popular family-owned supermarket that has been operating at its current location in Collins, Missouri, since 1996. The availability of federal tax credits, coupled with a $12,500 incentive from Empire District Electric Company for commercial PV systems, piqued the interest of Ray Marquis, the grocery’s owner. His goal was simple—fit as many modules on the market’s roof as possible.

Array shading is a common concern for many solar projects in southwest Missouri, where PV installations often require the removal or trimming of nearby trees. Localized shading is one reason Sun Solar began sourcing JinkoSolar Eagle MX modules with integrated Maxim cell-string–level optimization from its wholesaler, CivicSolar, in early 2016. These modules use integrated circuits (ICs) to track MPP at the cell-string level. The IC isolates shaded cells within the module and scales up the output current to match the string current. This arrangement optimizes each cell group to operate independently at its unique MPP. JinkoSolar Eagle MX modules provide additional design flexibility by enabling uneven strings and even multiple orientations within a string.

While the rooftop of Buzz’s Market did not have any major shading concerns, roof obstructions—including plumbing vents on one of the roof’s orientations—create some periodic shading. The Sun Solar installation team slightly altered the original array design configuration to compensate for the roof obstructions. JinkoSolar Eagle MX modules are compatible with string inverters such as the Fronius Symo line designated in the design. The modules allowed Sun Solar to mitigate any losses associated with the roof obstructions, and the Fronius Symo inverters offer source-circuit flexibility that made it easy for Sun Solar to adjust the final layout and string design. Installation and commissioning procedures for JinkoSolar Eagle MX modules are identical to those for standard modules, and they do not have any module-specific inverter programming requirements. The string inverter’s MPP tracker or trackers further optimize the output of its aggregated source circuits.

The installation took 11 days from start to finish, including the time required to adjust the array’s design layout. The market’s low-slope trapezoidal rib-metal roof was a great candidate for S-5!’s ProteaBrackets, and S-5!’s PV Kits were a streamlined choice for module mounting. Sun Solar mounted the six Fronius inverters at ground level, in close proximity to the building’s utility service. Once the integrator team members confirmed the final array capacity of the system, they worked quickly to get the job installed and commissioned with the utility.

“Buzz’s Market is one of the bigger jobs Sun Solar had the pleasure of installing this year. The design flexibility of the equipment used made it simple. The combination of JinkoSolar modules and Fronius Symo inverters made it easy on us as an installer and provides the customer with a high-performance solution and increased return on investment, from which they’ll benefit for years to come.”

Luke Arthur, chief operating officer, Sun Solar 

Overview

DESIGNER: Jerry Bergstrom, solar designer, Sun Solar, ussunsolar.com

LEAD INSTALLER: Chris Neal, installation crew lead, Sun Solar

DATE COMMISSIONED: September 14, 2016

INSTALLATION TIME FRAME: 11 days

LOCATION: Collins, MO, 37.9°N

ASHRAE DESIGN TEMPERATURES: 93.2°F 2% average high, -2.2°F extreme minimum

ARRAY CAPACITY: 93.28 kWdc

ANNUAL AC PRODUCTION: 132,126 kWh

Equipment Specifications

MODULES: 352 JinkoSolar Eagle MX JKMS265PP-60, 265 W STC, +3/-0%, 8.88 Imp, 29.8 Vmp, 9.51 Isc, 36.7 Voc

INVERTERS: 120/208 Vac 3-phase service, four Fronius Symo 15.0-3 208 inverters (15 kWac, 1,000 Vdc maximum input, 325 Vdc–850 Vdc MPPT range), two Fronius Symo 12.0-3 208-240 (12 kWac, 600 Vdc maximum input, 300 Vdc–500 Vdc MPPT range)

ARRAY: 16 modules per source circuit (4,240 W, 8.88 Imp, 476.8 Vmp, 9.51 Isc, 587.2 Voc), four source circuits per 15 kW inverter (16.96 kW, 35.52 Imp, 476.8 Vmp, 38.04 Isc, 587.2 Voc), three source circuits per 12 kW inverter (12.72 kW, 26.64 Imp, 476.8 Vmp, 28.53 Isc, 587.2 Voc), 93.28 kWdc array total

ARRAY INSTALLATION: Exposed fastener trapezoidal rib metal roofing panels, S-5! ProteaBracket and S-5! PV Kit attachment system, 182° and 2° azimuths, 3° tilt

SYSTEM MONITORING: Fronius inverter-integrated data monitoring, Fronius Solar.web online platform

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