A project is provided with perimeter induction units with internal coils for cooling and heating. Central dedicated 100% outdoor air handling unit feeds the induction units with fresh air, and the perimeter units induce own space return. So, for the induction unit, fraction of local recirculation air the is representative of system RA is 0. i.e. Er = 0.
Also, even though the induction unit has own coils for cooling and heating, they are for conditioning space returns only because it intakes fresh air from central DOAS which already conditioned.
If that is the case, do I need to prepare separate 62.1 calculation sheets for each perimeter unit because it has own coils assuming they are as individual ventilation system?
Or, I assume the induction unit coils as separate coils for space return only and does not affect space ventilation. So, how about ignoring the space coils and prepare one calculation sheet from a point of view of central DOAS only because it provides all the fresh air to perimeter units?
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Ben Stanley
Senior Sustainability ManagerWSP - Built Ecology
LEEDuser Expert
250 thumbs up
August 18, 2016 - 4:11 pm
Did you confirm the appropriate approach for this situation?
Normally, the system level is defined to be the point at which outdoor air is mixed with return air. In this case it sounds like that would be at each individual induction unit.
But, maybe if you only considered the primary airflow (outdoor air) at the DOAS and the induction units in the calculation and did not account for the local recirculated air, you might be able to set it up as a single system.
I'd confirm the approach with GBCI before finalizing the documentation.