For solar PV design, the ASHRAE highest month 2% dry bulb temperature for San Jose, CA is important because it is used to estimate the highest continuous ambient temperature, which is a critical factor in determining the expected performance of the PV modules under typical operating conditions.
The ASHRAE highest month 2% dry bulb temperature represents the maximum temperature that can be expected during the hottest month of the year, with only a 2% probability of exceeding this value. This temperature is used as a starting point to estimate the highest continuous temperature that a solar PV module is likely to experience over an extended period of time, usually for several weeks or months.
The highest continuous temperature is important because it affects the efficiency and performance of solar PV modules. As the temperature of a PV module increases, its output voltage and current decrease, which can result in a decrease in the overall power output of the module. By estimating the highest continuous temperature that a PV module is likely to experience, designers can ensure that the module is designed to operate within safe temperature limits and that the system will perform optimally under expected environmental conditions.
In the case of San Jose, CA, the ASHRAE highest month 2% dry bulb temperature is 101°F (38.3°C), which can be used as a starting point to estimate the highest continuous temperature that a solar PV module is likely to experience in this location.
|Location||Highest month 2% dry bulb temperature (°F)|
|San Jose, CA||101|
The operating temperature of a solar PV module can have significant effects on its voltage and current output. As the temperature of a solar PV module increases, its output voltage and current decrease.
In general, an increase in temperature causes an increase in the intrinsic carrier concentration of the semiconductor material used in the PV cell, which in turn leads to a decrease in the open-circuit voltage and a decrease in the short-circuit current. This is due to the reduction in the built-in potential of the p-n junction, which reduces the voltage output of the cell, and an increase in the rate of recombination of charge carriers, which reduces the current output of the cell.
The decrease in voltage and current output due to temperature effects can lead to a reduction in the overall power output of the PV module, which can have a significant impact on the performance of a solar PV system. Therefore, it's important to properly account for the effects of temperature on the performance of the PV modules in the design of a solar PV system, to ensure that the system is designed to operate within safe temperature limits and to maximize the power output of the system.