Measurement of temperature coefficient of photovoltaic modules in field and comparison with laboratory measurements

The performance of photovoltaic modules depends on temperature and irradiance. It is necessary to translate the measured I-V characteristics to standard test condition for assessing degradation, and such translations require temperature coefficients for voltage and current. Prediction of the annual energy yield also requires knowledge of the temperature coefficients. IEC 60891 provides a standard procedure for measurement of temperature coefficients and this methodology has been utilized to obtain the temperature coefficients of modules of different PV technologies, both in laboratory and in the field. Comparison of the values obtained in the field with those of the laboratory show good conformance. Also the variation of the temperature coefficients with change in irradiance has been investigated.