Final answer:
For a stationary PV array, the optimal tilt angle is the site latitude of the location, optimizing the annual yield. Tilting the panels at an angle equal to the latitude of the site facing the equator will maximize the total annual insolation. The study by the National Renewable Energy Lab in St. Louis, showed that tilting the panel at the site latitude delivers an annual average of 4.8 kWh/m²/day.
Step-by-step explanation:
For a stationary (nontracking) PV array, the total annual insolation is maximum for a tilt angle equal to the site latitude of the location. This means that tilting the solar panels at an angle equal to the latitude of the site, facing towards the equator, will optimize the annual yield of the PV array. The study conducted by the National Renewable Energy Lab in St. Louis, Missouri, showed that tilting the panel at the site latitude delivers an annual average of 4.8 kWh/m²/day, matching the graphic expectation from Figure 13.11.