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pingswept / pysolar

Pysolar is a collection of Python libraries for simulating the irradiation of any point on earth by the sun. It includes code for extremely precise ephemeris calculations.
http://pysolar.org
GNU General Public License v3.0
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Question: get_radiation_direct() #92

Closed paulocheque closed 5 years ago

paulocheque commented 5 years ago

... get_radiation_direct() returns a value in watts per square meter ...

What is the period of time that represents the result of this function? An entire day? I mean, I get a value 909 like in the example, so I can interpret:

the average insolation for that lat/long point is 909 W/m2 in the 5th day of the year 2018

Is that correct?

And what about the 0.8 version? Should it return 0s at night?

I am asking because of this comment: As of version 0.7, the function is not smart enough to return zeros at night

paulocheque commented 5 years ago

The other thing, I saw this function doesn't use the azimuth, only the altitude. Is that expected? That is because the value is an average of the entire day?

jeromelebel commented 5 years ago

I guess your square meter on the ground receive sun according to the sun altitude and according to the time of the day. So it is not Wh for the day, but W at specific time of the day. The square meter on the ground doesn't care if the sun arrives from the east, the south, or the west.