I'm modeling a lab by E+. I need to consider fume hood exhaust and air change rate and the same time. there would be 2 air volume working at the same time (choose the bigger one at any time), and use different schedule. what should I do to simulate this kind of model?
thank you!
Exhaust air is modeled with Fan:ZoneExhaust which has an optional field for "Flow Fraction Schedule Name" to control the flow rate.
By "air change rate" I am guessing that you mean the air flow from a variable-volume (VAV) air loop. If it is providing 100% outdoor-air, then use the airterminal unit field for "Design Specification Outdoor Air Object Name" to control the minimum damper position. In the DesignSpecification:OutdoorAir object, specify the ACH and schedule. If it is not 100% outdoor air, then use the air terminal "Minimum Air Flow Fraction Schedule Name" to control the minimum flow rate.
If you want the air loop to supply all of the makeup air for the hoods, then you have two options:
1. Define both schedules, run a simulation and output Output:Variable,*,Schedule Value, timestep;. Then use a spreadsheet to compare the exhaust flow rate and minimum ACH and create a custom ACH schedule that tracks the greater of the two. Then save this schedule to a csv file and use Schedule:Fileto import it and apply it to the terminal unit
2. Use an EMS program to check both values and override the ACH schedule.
thank you for your help！o(￣▽￣)ｄ
Comments
and how to control the exhaust air volume and schedule?