Issue overview

Fan:ZoneExhaust should have no impact on the conditions or load in a zone that is served only by zone equipment (unless used with AirflowNetwork or ZoneAirMassFlowConservation). The exhaust fan should simply consume electricity, and it is assumed that the user has specified infiltration or interzone mixing to offset the exhaust flow.

A user reports that a single zone model with four pipe fan coil (no outdoor air flow) and zone exhaust fan does not produce reasonable results. With zone equipment, one would expect that the "balanced flow" schedule for the exhaust fan would have no impact, but it changes the results significantly. There are three test files, one with no exhaust fan, one with exhaust fan and balanced flow=0, and another with exhaust fan and balanced flow = 1. These should all produce the same results (other than the exhaust fan electricity), but they do not.

Workaround

Delete the exhaust fan and use ElectricEquipment with 1.0 Fraction Lost to model the fan power.

Details

Some additional details for this issue (if relevant):

• Platform Win64
• Version of EnergyPlus v8.7.0
• Helpdesk ticket number 11987

Checklist

Add to this list or remove from it as applicable. This is a simple templated set of guidelines.

• Defect file added DevSupport\DefectFiles use Sacramento weather.
• Ticket added to Pivotal for defect (development team task)
• Pull request created (the pull request will have additional tasks related to reviewing changes that fix this defect)