Residential Grid-Direct Photovoltaic System: Klinken Residence

The Klinken residence was originally conceived of as a clean energy project. This passive solar home was built in 1985 with a roof that was designed to accommodate PV when the economics became favorable. In the summer of 2009, with the elimination of the federal tax credit cap, the Klinkens decided the time was right. Their goals included developing a conservative, long-term financial investment; reducing carbon emissions; supporting the solar industry; and helping the nation’s economic recovery in their own small way.

After receiving multiple bids, the Klinkens selected Sunnyside Solar Energy of Parkton, Maryland, to install their PV system. The company’s experience in both PV and solar thermal design and installation was valuable to this project. In order to minimize shading of the planned PV array, the existing thermal collectors located on the upper roof were moved to the lower because the thermal system would not be significantly impacted by the resulting morning shading. Hydronic loops were added in a small greenhouse to serve as a heat dump for the oversized thermal system that had been installed by a previous contractor. Skylights were removed to make room for more PV modules. In order to maximize the energy production from the available roof area, Sanyo HIT modules, sourced from SunWize Technologies, were selected due to their high power density.

“Creatively finding enough roof space to install the PV system size the Klinkens wanted was a significant challenge for this project. Our thermal expertise allowed us to discover a design flaw in the existing thermal system and coordinate its relocation and upgrade. Even though this meant more upfront cost, it allowed both systems to be more efficient. We help clients understand the big picture by not only designing their solar energy systems, but also by identifying ways they can reduce their energy usage in the first place.”

Rich Louis, Sunnyside Solar Energy

Overview

DESIGNER AND LEAD INSTALLER: Rich Louis, partner, Sunnyside Solar Energy, sunnysidesolarenergy.com
DATE COMMISSIONED: July 2009
INSTALLATION TIME FRAME: 7 days
LOCATION: Davidsonville, Maryland, 38.9°N
SOLAR RESOURCE: 4.65 kWh/m2/day
RECORD LOW/AVERAGE HIGH TEMPERATURE: -7°F / 87°F
ARRAY CAPACITY: 7.31 kW STC
AVERAGE ANNUAL AC PRODUCTION: 8.9 MWh

Equipment Specifications

MODULES: 34 Sanyo HIT Power 215N, 215W STC, +10/-0%, 5.13 Imp, 42.0 Vmp, 5.61 Isc, 51.6 Voc
INVERTERS: One Fronius IG 3000, 500 Vdc maximum input, 150–450 Vdc MPPT range; one Fronius IG 4000, 500 Vdc maximum input, 150–450 Vdc MPPT range
ARRAY: One 14-module subarray with seven modules per string (1,505 W, 5.13 Imp, 294 Vmp, 5.61 Isc, 361.2 Voc) with two circuits to the IG 3000 inverter (3,010 W, 10.2 Imp, 294 Vmp, 11.2 Isc, 361.2 Voc) and one 20- module subarray with five modules per string (1,075 W, 5.13 Imp, 210 Vmp, 5.61 Isc, 258 Voc) with four circuits to the IG 4000 inverter (4,300 W, 20.5 Imp, 210 Vmp, 22.4 Isc, 258 Voc)
ARRAY INSTALLATION: Roof mount on asphalt shingles, Unirac Solar Mount racking system, 190° azimuth, 39° tilt
ARRAY COMBINER: MidNite Solar MNPV6 for 20-module array, 15 A fuses
MONITORING: Utility and inverter based kWh meters

Article Discussion

Related Articles