We are working on a project that has a fancoil located on the top of the building that will treat the outdoor air and deliver it to each non densely occupied zone. This air will be mixed with the recirculated air and will be treated again to reach the temperature required by the occupant. We would like to know if installing the outdoor airflow device on the fancoil located on the top of the building will attempt the requirement for non densely occupied spaces of this credit or is it necessary to install this device on each zone equipment (fancoil serving each zone)?
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Dylan Connelly
Mechanical EngineerIntegral Group
LEEDuser Expert
472 thumbs up
February 3, 2012 - 7:35 pm
Is that fan coil unit constant volume? 100% OSA? Or variable volume with minimum OSA? Hard to say without more information. But, it sounds like the outdoor airflow device on the fan coil is sufficient.
Carolina Vergnano
LEED APConcremat
145 thumbs up
February 6, 2012 - 5:38 am
Thanks Dylan.
So, the fancoil located on the top of the building will be at a constant volume of 100 % outdoor air and it will treat the outdoor air before goes to each fancoil units located in the zones.
My doubt is, if I install the outdoor airflow device on this fancoil (the fancoil located on the top of the building), I'll know for sure the total of outdoor air that is coming in the building, but I won't know, for sure, the right volume of air that goes to each zone.
As the outdoor air will be mixed with the recirculated air at the zone, the calculation of outdoor air (required for IEQp1c2), will be the "single-zone system".
Dylan Connelly
Mechanical EngineerIntegral Group
LEEDuser Expert
472 thumbs up
February 6, 2012 - 11:37 am
The outdoor airflow sensor on the fan coil unit will be sufficient (include an alarm for OSA dropping 10% below design). The contractor will test and balance the ductwork running to each zone FCU to ensure the right volume of OSA to each zone. The airflows then shouldn't vary drastically through the life of the system.
Beyond LEED, you may also want to consider the temperature of the OSA and ensuring that the air can flow through the zone FCUs into the space even if the FCU is off (i.e. zone temperature is reached but the space is still occupied). Consult your ME.
Phillip Cook
WGE5 thumbs up
October 31, 2013 - 12:17 am
This is a great response, however, I am a bit confused about how to fill out the form.
I have two constant volume 100% OA AHU that each distribute to multiple fan coil units in multiple zones. So I plan on installing only 2 OA measurement devices (one for each AHU). But in the form, it asks for AHU / Zone combo on each line - do I:
1. Enter all ~23 zones for each AHU as I did in IEQP1 and if so, do I tick each zone as having a OA measurement device?
2. Enter two zones (one for each AHU) and mark these as both having a OA measurement device but then this does not match the zones on IEQp1 form?
Any assistance would be much appreciated.
Dylan Connelly
Mechanical EngineerIntegral Group
LEEDuser Expert
472 thumbs up
January 24, 2014 - 9:37 pm
Just enter the 2 AHUs as having measurement devices