Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
Via Matt Larson at Big Ladder Software:
EnergyPlus will pull the SummerDesignDay and WinterDesignDay values from the schedule for the days specified in the SizingPeriod:DesignDay objects. So typically, the SizingPeriod:DesignDay for the WinterDesignDay falls on 1/21 in the example files, and EnergyPlus will grab the the WinterDesignDay value for that time period, or in your second schedule definition, the value in ‘Through: 6/1’. The SummerDesignDay is usually specified for 7/21 in the example files, so it would grab the schedule values for SummerDesignDay for that time period, or in ‘Through: 12/31’ in your second schedule definition.
In your first single DD definition above, the WinterDesignDay value would be 21.11 and your SummerDesignDay value would be 23.89. Basically you just want to ensure you have the WinterDesignDay and SummerDesignDay specified correctly for the time period that contains the date defined in the SizingPeriod:DesignDay objects for their respective design days.
