PV*SOL Expert 6.0 - Manual - Valentin Software

10.1.8 Losses
10.1.8.1 Losses at the PV Generator
System > Technical Data > Losses > Array i
The array’s power output (DC side) is, along with the STC efficiency and the calculated
output, determined by the part load operation, the output’s temperature dependency (see
output coefficient in the PV Module dialog) and the additional losses.
-> Proceed as follows:
1. Enter the following losses, which occur during real system operation:
o Deviation from Standard Spectrum AM 1.5:
Spectral mismatch changes the module’s characteristic curve, which is
measured against a standard spectrum. In Central Europe a correction
factor of an annual average of 2% can be allowed for. The correction factor
should be entered in the field provided.
o due to Mismatch or Lesser Yield Due to Deviation from Manufacturers
Info:
Despite equal irradiation and temperature, different MPPs (mismatching)
can occur because of production tolerances, or because the modules do not
reach their full power as stated by the manufacturer (lesser yield). These
kind of power losses can reach 1-5%. (This does not mean the ”mismatch
effect” that occurs if differently aligned modules, ie a number of arrays, are
connected to a single system inverter. These losses are defined during
simulation.)
o in Diodes:
Losses caused by a drop in voltage by the modules’ blocking diodes can
usually be ignored.
o due to Pollution:
Over a certain tilt angle (approx. 20%) losses caused by pollution can be
ignored.
2. Irradiation Gains:
o Ground Reflection (albedo) is evaluated in the radiation processor. PV array
irradiation is increased by the reflection of radiation on the ground or in the
surrounding area. With a ground covering of snow the albedo is 80%, under
normal conditions the albedo is 20%.
Enter the average annual ground reflection (albedo).
o Or enter the monthly albedo.
3. From the system height above ground level it is possible to determine the scalar
wind at system height for the dynamic Temperature Model. The wind in the
climate data is measured at a height of 10 meters.
Enter the height of the PV system above ground.
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