Research on the photoelectricity mismatch loss of photovoltaic and thermal (PV/T) units connected in series at different temperatures

Abstract

Abstract A simulation study was conducted on the mismatch loss caused by temperature differences between photovoltaic and thermal (PV/T) modules connected in series. A calculation method for the IV curve of PV/T modules connected in series was proposed, and an equivalent circuit model of PV/T units was established using Multisim software. Two different temperature zones, three different temperature zones, and four different temperature zones of PV/T units connected in series were separately established. A numerical calculation model based on the Lambert W function was used to study the series mismatch characteristics of PV/T cells at different temperature ranges. The series connection method of PV/T modules obtained through experimental comparison research: (1) The maximum temperature difference of PV/T modules in the series should be controlled within the range of 10-20°C as much as possible; (2) The temperature of adjacent PV/T modules in the string should achieve continuous distribution; (3) Considering that the maximum operating current of a concentrated PV/T system is greater than that of a regular photovoltaic system, it is necessary to reduce the system output current and increase the system output voltage as much as possible in engineering. A series connection should be the main connection method for a string connection.