Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
Yes, by default EnergyPlus will try to autosize each component to meet the full load calculated from the design day. Some objects have input fields to change this, like the baseboard heater, but most do not (terminals, window air conditioners, etc.). In the case of terminals, EnergyPlus needs the DesignSpecification:AirTerminal:Sizing object added to the input file so that you can set adjusted capacities, supply temperatures, or flow rates from the design day. There is a similar DesignSpecification:ZoneHVAC:Sizing object that makes similar adjustments to zone HVAC components (window air conditioners, etc.).
Currently, both of these options are not available in either the OpenStudio Application or the OpenStudio SDK. If you want to incorporate these objects into your OpenStudio workflow, you will need to do so through an EnergyPlus measure that adds EnergyPlus objects to the input file created by OpenStudio -- something like Inject IDF Objects could work.
An alternative would be to avoid EnergyPlus measures and to manually hard-size the terminal once you know the final baseboard heater capacity.
