Could you please tell us what
happens when I include two summer design days in my model idf? Does E+
uses the worst? Uses the last? Is OK to include more than 1 design day
per season?
Let's see, what do you think happens? As ASHRAE HOF states, the
design conditions may respond differently depending on systems,
etc.
I think you have to include two or more summer design days to tell
exactly what effect it will have. If you are talking sizing that is
-- the day chosen to represent the sizing is shown in the zsz and ssz
files, i believe. (Described in the Output Details
document).
You can put in all the design days in a ddy file == so, yes, you can have
more than one design day per season. If you then choose to run the
"sizing periods" from the Simulation Control, then you will see
the different loads. (You might choose to make the day of month
different so it will stand out better in the csv file)