Nominal/Normal Operating Solar Cell Temperature(NOCT) – Definition, Glossary, Details – Solar Mango

A PV module will be typically rated at 25 °C under 1,000 watts per square meter. However, when operating in the field, they typically operate at higher temperatures and at somewhat lower insolation conditions. In order to determine the power output of the solar cell, it is important to determine the expected operating temperature of the PV module. The Nominal Operating Cell Temperature (NOCT) is defined as the temperature reached by open circuited cells in a module under the conditions as listed below:
Irradiance on cell surface = 800 W/m2
Air Temperature = 20°C
Wind Velocity = 1 m/s
Mounting = open back side.