I am quite new to HB and have an issue to model ventilation that is demand controlled.
In the HBSetSchedule component is written for the ventilation schedule :
"Note that this schedule overrides the typical ventilation that occurs based on the occupancy shcedule and the “ventilationPerPerson.”
So I guessed if we didn’t put a schedule there and specify a minimum airlow/m2 and minimum airflow/occupant, EP would calculate the volume flow rate at each timestep based on the schedule, but it doesn’t seem to work.
Indeed, on the results, I only have a constant airflow that correspond to the maximum of vol/m2 and vol/occ. So I wonder how to use these components to have demand controlled ventilation.
What I really want is have a minimum airflow when the room is not occupied and a bigger one based on the number of occupants when the room is occupied.
I currently have :
outdoorAirRequirement input = 1 (maximum) in SetEPZoneThreshold
ventilation per area = 0.00035
ventilation per occ = 0.01 in set EPZoneLoads
No ventilation schedules input in SetEPZoneSchedules
Create a new schedule with the values of the occupancy file with a function that substitute the values=0 (when there is no occupancy) for the amount that you need. You can always calculate this value by inputting a fraction of the ventilation per area or per person, as suits you.
Hope it helps
Julia
Edit: keep in mind that the simulation will calculate the ventilation per area/person multiplied by the number of the new schedule (approx to explain it in a simple way, hope Mostapha doesn’t kill me for saying that), so be very careful with the numbers that you put there
This is approximately the way I am doing it right now but it requires quite a few unit conversions before having the right input and therefore higher risk of making a mistake…
In was therefore wondering if there was a nicer way to do it using the inputs already existing in the different components
PS : This workflow is quite useful to modify a schedule ! Thanks !
Unfortunately not that I know/ remember in this moment. Maybe someone else can help you better.
I know the possibilities of mistaking are high. What I do in these cases usually is I check thousands of times with other colleagues and run tests on small boxes to check its fine, and when I’m happy I cluster it, so I don’t change it by accident.
