One year NOCT Round-Robin testing per IEC 61215 standard

The nominal operating cell temperature (NOCT) was developed as a reference characterization test procedure to quantify the module cell temperature for different module designs in a standard reference environment (SRE) of 20 °C ambient temperature, 800 W/m² irradiance and 1 m/s wind speed [1]. The NOCT value is a key performance parameter to be measured as per the IEC 61215 (Edition 2) standard, and it is required to be independently measured and reported to qualify for the incentive programs of various agencies including California Energy Commission. Ideally, the NOCT value of a specific module design should be identical irrespective of testing laboratory, location, month or season. The objectives of this NOCT Round-Robin testing were: (i) to identify if NOCT values are significantly influenced by the testing approach or site specific test conditions experienced by different labs in the world (referred to as reproducibility); (ii) to identify if NOCT values are dependent on the month or season within any single laboratory (referred to as repeatability), and (iii) to identify if NOCT values are significantly influenced by the type (thermocouple or RTD) and position (backsheet or cell) of thermal sensor used by different labs in the world. A total of eight polycrystalline silicon modules with a nameplate rating of 217 watts were continuously tested over a year in eight different test laboratories around the world, one at each participating laboratory. All test samples are of the same model, were supplied by a single manufacturer, were received as a batch and were assumed to be identical with no variability in manufacturing. The test laboratories were not supplied with any specific testing procedure and they were asked to perform the testing as per their established standard operating procedures (SOP).