Evaluating optimum tilt angle for PV modules using solar radiation models in Wuhan, China

Four models are used to estimate the hourly solar radiation on 15 pieces of different tilted photovoltaic (PV) modules in Wuhan, China based on power and solar radiation data during a whole year. The optimum tilt angle (OTA) in Wuhan for yearly and semi-yearly adjustment was determined. Then it was determined that the best mode is the tilt angle of PV module adjusted every half a year. In semi-yearly adjustment, OTA in semi-year of winter and summer is found as 45°, 15°, respectively. Experimental results verify the theoretical calculated values of the OTA with high precision. Energy radio (ER) reveals PV modules with adjustment of tilt angle twice a year has a capability to improve nearly 7% in comparison with fixed type. The best model was chosen based on test results from statistical indicators. The statistical results demonstrate that among the studied models, Liu&Jordan model is the most accurate.