Effect of ambient temperature

Effect of ambient temperature

The output power of a PV module depends on the temperature at which the solar cells operate. It is important to note that module temperature is always higher than the ambient temperature. The higher temperature of the module is due to the use of glass cover which traps the infrared radiation. The increase in temperature result in the reduction of band gap of the PV cells in the module. This leads to the increase in ISC but decrease in VOC. The decrease in VOC is more prominent than increase in the ISC.

Therefore, overall power output and efficiency of the PV cells decreases with the increase in its operating temperature. The effect of temperature on the I–V curve of the PV module is shown in Fig. 2. The efficiency of Poly-crystalline PV cell is more influenced by temperature as compared to mono-crystalline and amorphous silicon cells. With the rise in temperature efficiency of mono-crystalline PV cell is found to decrease by 15% whereas amorphous PV cell by 5%. As the temperature increases, power output and efficiency of PV module decreases and becomes

minimum at the stagnation temperature. Higher module temperatures also results in degradation of cell-wires, encapsulate as well as influences the module life time in the field.