4.05 kW Solar Electric System in Liverpool, NY
Challenge
This 4,050 W (4.05 kW) grid-connected solar electric system was installed as a roof-mounted array of eighteen (18) SunPower 225W solar modules oriented South on the main roof of the Customer's house.
Solution
This 4,050 W (4.05 kW) grid-connected solar electric system was installed as a roof-mounted array of eighteen (18) SunPower 225W solar modules oriented South on the main roof of the Customer's house. The array is arranged as three rows of five modules and one additional row of three modules in landscape, as illustrated in the accompanying schematic. The modules are mounted at the same pitch as the client's roof (18.4 degrees) using a UniRac SunFrame racking system. The array layout is designed to maximize system size and future expansion, while allowing only minimal losses due to shading and ensuring the system is aesthetically pleasing and well-integrated with the house. The system is configured electrically as two (2) DC circuits (strings) of nine (9) series connected modules providing input through one (1) DC disconnect switch to one (1) SunPower 4000m, 4.0kW inverter. This inverter provides grid-synchronous AC output and interfaces to the electric utility through a dedicated circuit breaker in the Customer's main service panel, as existing infrastructure allows. System power production (kW) and cumulative energy (kWh) monitoring is provided by a SunPower Monitoring System, as well as by a digital display on the inverter and an electromechanical meter. As designed, this system should generate 4,139 kWh per year, for an average of 11.3 kWh/day, where daily energy production is both weather and seasonally dependent. This energy production is equivalent to 28% of the customer's present home electrical usage, and corresponds to a CO2 (greenhouse gas) emissions savings of 5,381 lb per year.
