Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
No, there is currently no way to only operate the exhaust fan only when the economizer is active. The work-around you propose, i.e. modeling a fan on the relief air segment, is the best solution. The relief fan will operate at the minimum outdoor air flow when the economizer is not active. However, if the fan is variable speed, the amount of energy used at this low part-loads will be small.
