Article,
On the clear sky model of the ESRA with respect to the Heliosat method
Solar Energy, 68 (1): 33--48 (2000)
Abstract
AbstractâThis paper presents a clear-sky model, which has been
developed in the framework of the new digital European Solar Radiation
Atlas (ESRA). This ESRA model is described and analysed with the
main objective of being used to estimate solar radiation at ground
level from satellite images with the Heliosat method. Therefore it
is compared to clear-sky models that have already been used in the
Heliosat method. The diffuse clear-sky irradiation estimated by this
ESRA model and by other models has been also checked against ground
measurements, for different ranges of the Linke turbidity factor
and solar elevation. The results show that the ESRA model is the
best one with respect to robustness and accuracy. The r.m.s. error
in the estimation 22 22 of the hourly diffuse irradiation ranges
from 11 Wh m to 35 Wh m for diffuse irradiation up to 250 Wh 22 m
. The good results obtained with such a model are due to the fact
that it takes into account the Linke turbidity factor and the elevation
of the site, two factors that influence the incoming solar radiation.
In return, it implies t
