the tag for an air terminal unit equip is modeled as "vav", but that does not accurately describe a constant air volume air terminal unit. I have read many threads that tangentially discuss this, but no conclusion seems to have been made. We have thought that the tag "airTerminalUnit" or something similar could be used for all air terminal units, and the tag "constantVolume" and "variableVolume" (which are currently proposed only for AHUs) could be used to further describe them. Does this sound like a decent solution or is there something we are missing that has already been proposed?
Thanks!
Jordan Van HallTue 4 Sep 2018
+1 to Holly's question
On projects with many types of terminal units, including traditional VAVs and constant volume air terminals with reheat (e.g., perimeter heating), how are folks tagging and modeling those?
Jay HerronTue 4 Sep 2018
I completely agree, Holly. Internally, we have been using tu alongside vav for the exact reason you mention. I would support replacing or qualifying the vav tag with a terminal unit tag, whether it is tu, terminalUnit or something else.
Jordan Van HallFri 7 Sep 2018
Makes a lot of sense, Jay. At that point, it feels like the vav tag for tu is redundant with variableVolume and constantVolume. Currently those tags are exclusive to ahu equips, but really seem to just apply to any equip with a fluid medium.
So tuvariableVolume is equivalent to vav, whereas tuconstantVolume would describe a constant air volume "unit," such as a damper-less duct reheat terminal or a zone where min flow setpoint = max flow setpoint (i.e., constant volume).
"cav" is not a tag, but that term is used by a particular contractor as the alternative to VAV, whether it is a damper-less unit served by a constant volume AHU or a VAV box on a VAV AHU for a zone with constant flow setpoints.
Holly Hofer Fri 31 Aug 2018
Air terminal units
the tag for an air terminal unit equip is modeled as "vav", but that does not accurately describe a constant air volume air terminal unit. I have read many threads that tangentially discuss this, but no conclusion seems to have been made. We have thought that the tag "airTerminalUnit" or something similar could be used for all air terminal units, and the tag "constantVolume" and "variableVolume" (which are currently proposed only for AHUs) could be used to further describe them. Does this sound like a decent solution or is there something we are missing that has already been proposed?
Thanks!
Jordan Van Hall Tue 4 Sep 2018
+1 to Holly's question
On projects with many types of terminal units, including traditional VAVs and constant volume air terminals with reheat (e.g., perimeter heating), how are folks tagging and modeling those?
Jay Herron Tue 4 Sep 2018
I completely agree, Holly. Internally, we have been using
tualongsidevavfor the exact reason you mention. I would support replacing or qualifying thevavtag with a terminal unit tag, whether it istu,terminalUnitor something else.Jordan Van Hall Fri 7 Sep 2018
Makes a lot of sense, Jay. At that point, it feels like the
vavtag fortuis redundant withvariableVolumeandconstantVolume. Currently those tags are exclusive toahuequips, but really seem to just apply to any equip with a fluid medium.So
tuvariableVolumeis equivalent tovav, whereastuconstantVolumewould describe a constant air volume "unit," such as a damper-less duct reheat terminal or a zone where min flow setpoint = max flow setpoint (i.e., constant volume)."cav" is not a tag, but that term is used by a particular contractor as the alternative to VAV, whether it is a damper-less unit served by a constant volume AHU or a VAV box on a VAV AHU for a zone with constant flow setpoints.
Thoughts?