Consider a crystalline PV module with the following output parameters mentioned at STC (Standard Testing Condition) conditions by the manufacturer.
Pmax = 250W
Voc = 50V
Isc = 6A
NOCT = 40°C
Temperature coefficient of power = -1W/°C
a) If the ambient temperature falls to 0°C while the irradiance is 1000W/m², what is the cell level temperature in °C, as per the NOCT model?
b) What is the new power output of the PV module in Watts, under the ambient temperature of 0°C and 1000W/m² irradiance?
25
250
1) 25
2) 250
a) To determine the cell level temperature (Tcell) in °C using the NOCT model, we need to consider the temperature coefficient of power.
The NOCT (Nominal Operating Cell Temperature) model assumes certain conditions, including an ambient temperature of 20°C, an irradiance of 800W/m², and a wind speed of 1m/s. From this model, we can calculate the temperature difference between the NOCT conditions and the actual conditions.
The formula to calculate Tcell using the NOCT model is:
Tcell = NOCT + (Tamb - 20°C) * (NOCT coefficient / 800) + (Irradiance - 800) * (NOCT coefficient / 100)
In this case, the NOCT is 40°C, the ambient temperature (Tamb) is 0°C, and the irradiance is 1000W/m².
Substituting the values into the formula:
Tcell = 40 + (0 - 20) * (-1 / 800) + (1000 - 800) * (-1 / 100)
Simplifying the equation:
Tcell = 40 - 20 * (-1 / 800) + 200 * (-1 / 100)
Tcell = 40 + 0.025 + (-2)
Tcell = 38.025°C
Therefore, the cell level temperature in °C, as per the NOCT model, would be approximately 38.025°C.
b) To calculate the new power output of the PV module in Watts under the given ambient temperature of 0°C and 1000W/m² irradiance, we need to consider the temperature coefficient of power.
The temperature coefficient of power represents the change in power output per degree Celsius change in temperature. It is given as -1W/°C in this case.
The formula to calculate the new power output is:
Pnew = Pmax + (Tcell - NOCT) * (Temperature coefficient of power)
Substituting the values into the formula:
Pnew = 250W + (38.025°C - 40°C) * (-1W/°C)
Simplifying the equation:
Pnew = 250W + (-1.975W)
Pnew = 248.025W
Therefore, the new power output of the PV module, under the given conditions, would be approximately 248.025 Watts.