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EN-Rev IM/GN-AM-EU/2.81 Copyright © December, 2021. CSI Solar Co., Ltd.
www.csisolar.com
ANNEX B: GUIDANCE ON MODULE TEMPERATURE FOR SEVERAL LOCATIONS
The operational temperature of a PV module changes
during the day and also from day to day throughout the
year. The 98th-percentile temperature represents the
temperature that is larger than 98% of all the
temperatures, and consequently it is met or exceeded
only 2% of the time.
The 98th-percentile temperature is to be determined
from measurements taken on hourly-basis, or even
more frequently. For a standard year, the 98th-
percentile temperature would be met or exceeded
175.2 hours.
The operational module temperature is influenced by
the environmental temperature but also by how the
module is installed (e.g. mounting distance to rooftop,
array size, array spacing and anti-nesting features), as
it may allow a more efficient ventilation. The graphics
below from IEC 63126 show this influence, the maps
presented here are a general guidance and assumed
conservative, please contact your local sales
representative for further information.
For Open-rack it can be seen how the 70°C are never
exceeded in any of the locations, while for parallel to the
roof mounted modules (not in-roof) this value can be
surpassed for some locations.
Figure B.1 – 98th-percentile temperature for an open-rack, or thermally unrestricted
Figure B.2 – 98th-percentile temperature for a close-roof mounted
