Vmp is proportional to temperature
Voltage Temperature Coeff.
Every increase in temperature will affect the voltage in the module
Ideally the modules should have low temp. coff.
Crystalline - Mono Crystalline and Multi Crystalline have similar temp coeff.
Thin film - less temp coefficient - ideally for high temperature applications
Power Tolerence - Normal power tolerrence is 0% to 3%
Eg 100W Module will produce 100W to 103W
* But we must consider the system loss also
Series fuse rating
fuse rating 10A, 15A (up to 20A)
Testing labs for PV module UL
Standard - UL 1703 (for both mechanical and electrical)
Mechanical Characteristics can be taken from the specification sheet.
Standard Test conditions (STC)
Cell temp - 25"C / 77"F
Irradiance - 1000W/SqM
Air Mass - 1.5(AM 1.5)
Normal conditions of installation
Cell Temp - 75"C
Standard Irradiance - 0 to 1250W/SqM
From Technical specification sheet we need to take the Voc and Vmp
Typical value for Mono- and Multi-Crystalline module is
Voc - -0.35% / C"
Vmp - -0.5% / C"
-Ve means Negative temp coefficient, If temperature increases voltage decreses.
Difference in temperature = Cell temperature - STC
= 15'C - 25"C
= -10"C
Difference in temperature x Voltage Temp Coff.= % Change in Voltage
-10"C x -0.35'C = 3.5% Change in Voc
-10"C x -0.5'C = 5% Change in Vmp
Irradiance comparison with irradiance sensor (pyronometer)
Get the irradiance value using irradiance meter
Eg measured value - 650W/Sqm (this may vary from 200 to 1250)
STC of the cell is 1000W/Sqm
650W//Sqm = 0.65 - means 65% of the current should produce by the module
1000W/Sqm
*
*
*IV Curve of the module
*
*
*
Amount of current increases with temp is less so no need to consider this factor
IV curve with varying irradiance
Designer don't need to consider the irradiance on current, when designing the system
Voltage Temperature Coeff.
Every increase in temperature will affect the voltage in the module
Ideally the modules should have low temp. coff.
Crystalline - Mono Crystalline and Multi Crystalline have similar temp coeff.
Thin film - less temp coefficient - ideally for high temperature applications
Power Tolerence - Normal power tolerrence is 0% to 3%
Eg 100W Module will produce 100W to 103W
* But we must consider the system loss also
Series fuse rating
fuse rating 10A, 15A (up to 20A)
Testing labs for PV module UL
Standard - UL 1703 (for both mechanical and electrical)
Mechanical Characteristics can be taken from the specification sheet.
Standard Test conditions (STC)
Cell temp - 25"C / 77"F
Irradiance - 1000W/SqM
Air Mass - 1.5(AM 1.5)
Normal conditions of installation
Cell Temp - 75"C
Standard Irradiance - 0 to 1250W/SqM
From Technical specification sheet we need to take the Voc and Vmp
Typical value for Mono- and Multi-Crystalline module is
Voc - -0.35% / C"
Vmp - -0.5% / C"
-Ve means Negative temp coefficient, If temperature increases voltage decreses.
Difference in temperature = Cell temperature - STC
= 15'C - 25"C
= -10"C
Difference in temperature x Voltage Temp Coff.= % Change in Voltage
-10"C x -0.35'C = 3.5% Change in Voc
-10"C x -0.5'C = 5% Change in Vmp
Irradiance comparison with irradiance sensor (pyronometer)
Get the irradiance value using irradiance meter
Eg measured value - 650W/Sqm (this may vary from 200 to 1250)
STC of the cell is 1000W/Sqm
650W//Sqm = 0.65 - means 65% of the current should produce by the module
1000W/Sqm
*
*
*IV Curve of the module
*
*
*
Amount of current increases with temp is less so no need to consider this factor
IV curve with varying irradiance
Designer don't need to consider the irradiance on current, when designing the system
