I am testing a model representing a laboratory building. I am wanting to test ventilation setbacks to understand its effect on energy savings.
I am getting large discrepancies between the requested level of OA ventilation and the actual airflow delivered to the zone during simulation.
I managed to get around this by using a multiplication factor however, when i include a zone ventilation schedule that requests half the flow rate in unoccupied hrs i get no change in the simulated delivery. is there something else that could be governing the airflow delivered to the zone?
UPDATE: I have confirmed that the DesignSpecification:OutdoorAir object for the lab zones contains the correct schedule. @MingboPeng@chris is there something else that governs the airflow delivered to the terminal? and is the Zone air terminal outdoor air flow rate the right output to be measuring to investigate the amount of outdoor air being delivered to the zone?
I understand the Terminal sizing could have an effect but i have confirmed that they are being sized correctly and the requested airflow is within their minimum and maximum airflow rates.
It’s a little hard to understand the question without more context but it may help to know that the ventilation schedule in HB only affects the “dampers” on the outdoor air mixer. So dropping the schedule value for an hour should actually result in less outdoor air being mixed into the air stream (and corresponding less heating and/or cooling energy). But it does not usually change the total amount of air supplied through the terminal to each zone (since that includes both recirculated air and fresh outdoor air).
To actually see a change in air through the terminal, you need to set controls on the supply fan in the air loop. Some of the HVAC templates have properties that can be used to change this (like the dcv_ input on the HB DOAS HVAC component). But, if you are tying to apply a custom schedule to the fan, you may need to do so with Ironbug.
Hi Chris, thanks for your reply. Essentially i was looking for a way to confirm the requested outdoor air flow was delivered to the system but was having trouble finding the right custom output to call.