Design Day Creation[LINK]
How do I create the profile used in the SizingPeriod:DesignDay object?
Typically, the EnergyPlus Development Team uses the data from the most recent ASHRAE Handbook of Fundamentals to create a set of design day profiles that can be used. Description of ASHRAE’s data is contained in Chapter 14 of the 2009 Handbook of Fundamentals. Table shows the kind of data that is embodied in the design day definitions shown earlier (ref. Locations-DesignDays).
Design Days (aka Design Conditions) are very important for use in HVAC Sizing calculations – refer to the ASHRAE Handbook of Fundamentals for further information.
From this, you can determine if you should use one of these profiles and modify it or determine how to create your own profile.
The Weather Converter program accesses this file when it processes (even for statistics) a weather file. Design Day definitions are also included with the zips on the EnergyPlus weather data site. For locations that don’t have ASHRAE design conditions, the Weather Converter uses the data within the weather file to generate pseudo conditions in the statistics file.