Consider a crystalline PV module with the following output parameters mentioned at STC (Standard Test Conditions) conditions by the manufacturer.
Pmax = 300 W
Voc = 40 V
Isc = 8 A
NOCT = 40°C
Temperature coefficient of power = -2 W/°C
If the ambient temperature falls to 15°C while the irradiance is 1000 W/m², what is the cell level temperature in ºC, as per the NOCT model?
To determine the cell level temperature in ºC using the NOCT model, we need to use the given information and formulas.
1. NOCT (Nominal Operating Cell Temperature) is the temperature at which a PV module is expected to operate under normal conditions. It is defined as 20°C above the ambient temperature of 20°C. So, NOCT = 20 + 20 = 40°C.
2. The NOCT model assumes a decrease in module efficiency as temperature increases. The temperature coefficient of power (-2 W/°C) indicates the decrease in power output for every 1°C increase in temperature from the reference temperature, which is usually 25°C.
3. The temperature of the PV module can be calculated using the formula: T = NOCT + (TA - 20) * BTU / 1000
Where:
T = Cell level temperature in ºC
NOCT = Nominal Operating Cell Temperature (40°C)
TA = Ambient temperature (15°C)
BTU = Temperature coefficient of power (-2 W/°C)
Let's substitute the values into the formula:
T = 40 + (15 - 20) * (-2) / 1000
T = 40 + (-5) * (-2) / 1000
T = 40 + 10 / 1000
T = 40 + 0.01
T = 40.01°C
Therefore, the cell level temperature in ºC, as per the NOCT model, is approximately 40.01°C.