Ithaca, NY 12.15 kW Solar Electric System (Net-Zero Home)
Challenge
This 12,150 W (12.15 kW) grid-connected solar electric system was installed as a ground-mounted array of fifty four (54) SunPower 225 W solar modules oriented due South on three (3) Direct Power and Water adjustable-tilt top-of-pole mounts.
Solution
This 12,150 W (12.15 kW) grid-connected solar electric system was installed as a ground-mounted array of fifty four (54) SunPower 225 W solar modules oriented due South on three (3) Direct Power and Water adjustable-tilt top-of-pole mounts. Each pole holds eighteen (18) modules arranged in landscape and has dimensions of approximately 15.4 ft x 16.5 ft x 12.9 ft (width x height x depth) at 35° tilt, as illustrated in the accompanying schematic diagram. The system is configured electrically as six (6) DC circuits (strings) of nine (9) series connected modules providing input through three (3) DC disconnect switches to two (2) SunPower 6000m, 6.0 kW inverters. These inverters provide grid-synchronous AC output and interface to the electric utility through a single doublepole breaker and direct tap in the Client's main electrical service panel, or as existing infrastructure allows. System power production (kW) and cumulative energy (kWh) monitoring is provided by a custom web-based monitoring system, as well as by a digital display on the inverter and an electromechanical meter. As designed, this system should generate an average of 33.9 kWh/day (or 12,384 kWh/year), where daily energy production is both weather and seasonally dependent. This energy production corresponds to a CO2 (greenhouse gas) emissions savings of 44.1 lb CO2 per day (16,100 lb per year). Based on the analysis of the Customer's existing baseload and modeling of future needs with the geothermal heating system, this system will meet 170% of the customer's current electricity use and 84-101 % of the customer's projected electricity use.
