Just because you don't need to be bring OA in at night doesn't mean that you don't need to condition the zones, which means the supply fan must turn on.
During the day, the fan runs continuously to ensure the proper amount of OA, during the night, if there is a load, the fan turns on and off with the coils.
There is usually a fan operating mode schedule used with HVAC equipment that can cycle, or you can use a night ventilation manager to cycle the fan on for VAV systems.
OA control is independent of fan
operation (i.e., you can have OA or not if the fan is running).
On 8/16/2012 10:12 AM, Carolina Galeazzi wrote:
To build an ASHRAE baseline model, it's said that 'supply and return fans should be cycled to meet heating and cooling loads during unoccupied hours'. I understand that fans should run for mechanical ventilation, but with zero outside airflow rate. How can I cycle the variable volume fan of the AHUs in Eplus,
with zero outside airflow rate?
Thank you for your help!!
--
Richard A. Raustad
Senior Research Engineer
Florida Solar Energy Center
University of Central Florida
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