There are several reasons. One of them is below:
The output variable may give an averaged value of the preceding hourly period as the output listing.
Four your epw case:
When you simulate in time steps of more than 1, and list in timesteps, the ODT value at the hour is normally not changed significantly. ( epw ODT has only one decimal place.)
If you simulate in time steps of more than one and then list in hourly steps, the listed hourly value is averaged, and is the averaged value of the two adjacent values in the hourly epw data.
The averaging can happen on other output variables as well.
Date: Thu, 7 Apr 2011 13:52:02 +0000
Subject: [EnergyPlus_Support] EPW values different than E+ output of weather data
I've opened the EPW file and the E+ output:variables CSV file to compare. I've noticed that the temperatures, wind speed, etc. (outdoor data) are different. Can someone tell me why? THANKS!
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