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:
Hi All,
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!!
Carol
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