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Distinguished Contributor
kschindel
Posts: 144
Registered: ‎12-22-2008
Message 1 of 3 (302 Views)

pressure drop of VAV box and diffuser not included in duct pressure loss report

302 Views, 2 Replies
06-25-2013 06:36 AM

I created a duct system and am able to generate the duct pressure loss report where I see pressure drop of each fitting, duct etc.

 

I also have VAV boxes with (manually entered) pressure drop and diffusers with (calculated based on flow) pressure drop. but those pressure drops are not part of the loss report. How do i include those? Especially VAV loss is significant.

 

I attached the VAV box and diffuser families (which I took from manufacturers and modified).

Distinguished Contributor
kschindel
Posts: 144
Registered: ‎12-22-2008
Message 2 of 3 (240 Views)

Re: pressure drop of VAV box and diffuser not included in duct pressure loss rep

07-08-2013 05:50 PM in reply to: kschindel

I'm still struggling to get the pressure loss report to include the device pressure drops.

 

I even called the parameter "Pressure Drop" and gave some VAV boxes a 10 in-wg pressure drop. but no matter what I do, the duct pressure loss report only contains duct pressure drop (straight duct and fittings), but none of the VAV box, diffuser etc. pressure drops.

 

Is Revit actually really capable of calculating the duct system pressure drop, or should I use a different method? It seems fairly accurate for ducts, but the device pressure drop of course is significant.

 

I have the feeling I'm doing something wrong. I also played with the family duct connector "loss method" settings to no avail.

Distinguished Contributor
kschindel
Posts: 144
Registered: ‎12-22-2008
Message 3 of 3 (227 Views)

Re: pressure drop of VAV box and diffuser not included in duct pressure loss rep

07-09-2013 01:19 PM in reply to: kschindel

I kind of resolved half of my problem after I had an epiphany last night. For the VAV box I had to select the parameter for "Pressure Drop" to be what i wanted it to be and now the VAV box pressure drops show up.

 

I still have the problem that the diffuser (attached) doesn't seem to propagate its pressure drop. Actually it shows the pressure drop in the VAV system, but that pressured drop doesn't show in the entire AHU schedule.

 

when I just run a duct pressure loss report for the VAV system, i see the "air terminal" pressure drop. but when i run it for the entire AHU, none of the diffusers show up at all.

 

 

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