It uses many weather files -- not just based on TMY3.
These weather files include Solar Radiation values.
As shown in the Auxiliary Programs document, EnergyPlus uses the Direct
Normal and Diffuse horizontal values FROM the weather file. It does
not use Global Horizontal.
For Design Days, it depends on which Solar model the user chooses in the
DesignDay object.
At 10:13 AM 10/3/2012, saleh saadi wrote:
Dear Users,
I know that E+ uses a weather file based on TMY3 files in epw format.
Does E+ use the global horizontal , direct and diffusive solar radiation
from the weather file during simulation? or calculates internally the
direct normal and diffusive horizontal solar radiation using ASHRAE clear
sky model ?
Thanks,
Saleh AlSaadi