HomeMy WebLinkAboutB14-0266 calcs.pdf Page 4 of 6 7/7/2014 Calculations 13.5kW System Size (STC) 50 SolarWorld Plus SW270 mono solar modules @ 270watts 50 Enphase M-250 240v micro-inverters (4 string of 7/13/14/16) Array tilt angle: 26.57°/41.51° Array azimuth: 105º/195°/285° (where 180º is south) Estimated annual power production: 16,164kWh Maximum PV System Voltage: 690.7 Voc= 39.2V/module 39.2V x 1 module = 39.2V Temperature correction factor 690.7(A) STC = 25°C, Temperature Coefficient (Voc) = -.3%/°K (-65°C (-.003) = .195% ((.195% x 39.2V) x 1 panel) + 39.2V = 46.8V Temperature correction factor Table 690.7 For -40ºF use 1.25 39.2V x 1.25 = 49V Maximum PV Source Circuit (String) Current: 690.8 (A)(1) Isc =9.44A 9.44A x 1.25 = 11.8A Maximum PV Output Circuit (Array) Current: 690.8 (A)(2) 11.8A x 1 strings = 11.8A Inverter Output Circuit Current: 690.8 (A)(3) 1A @ 240V John Wiles, “Photovoltaic Power Systems and the National Electrical Code: Suggested Practices”, 2005, pp. E1-E25. pdf version online at: http://www.nmsu.edu/%7Etdi/Photovoltaics/Codes- Stds/PVnecSugPract.html