Flow overspecified at HVAC node.

Fast, accurate dynamic thermal simulation for energy/carbon modelling and much more...
anapaulaql
VE Newbie
VE Newbie
Posts: 1
Joined: Wed Jan 29, 2014 4:27 pm

Flow overspecified at HVAC node.

Postby anapaulaql » Tue Feb 04, 2014 4:02 pm

While I was working in an energy model for a two stories offices building,
when I ran the ApacheSim,I have received an error message that "flowrate over-specified at HVAC node
308/.
I will appreciate if anybody could advise on how to
rectify this...
Thanks
Ana

User avatar
Megan
Site Admin
Site Admin
Posts: 52
Joined: Thu Dec 12, 2013 3:03 pm
Location: Atlanta, GA

Re: Flow overspecified at HVAC node.

Postby Megan » Wed Feb 05, 2014 6:11 pm

Ana,

Open up your HVAC file in ApHVAC and select the "Check network" button. This will help you find node 308. Once you find the node, check the flow controllers you have that control the flow at that node. The "flow over-specified" error is telling you that there are too many controllers defining airflow at that point.

Since node 308 is outside of a multiplex, my guess is that you have a flow controller at the system level causing this particular problem. The flow controllers in the multiplex specify the airflow in the individual zones. The sum of those airflows is the flow required at the system level. No additional flow controller is needed. If you have a flow controller at the system level, it is over-specifying the flow. Delete it and the sim should run without any errors.

Thanks,
Megan

bootsam
VE Professor
VE Professor
Posts: 174
Joined: Fri Sep 10, 2010 1:15 pm

Re: Flow overspecified at HVAC node.

Postby bootsam » Fri Feb 28, 2014 9:23 am

Remove one of your flow controllers. For example if you have one main branch, splitting into 4 seperate. If you have a flow control on the main, then you only need to put one on three of the branches. For some reason HVAC doesnt like it on all 4. This is how I usually do it, then it works fine.

amirah_asilah
VE Newbie
VE Newbie
Posts: 1
Joined: Fri Jul 01, 2016 4:29 am

Re: Flow overspecified at HVAC node.

Postby amirah_asilah » Fri Jul 01, 2016 8:18 am

Hi,

In my case, the mentioned over-specified node is only a junction between 2 FCUs which dont have any component or controller there. The FCUs serve by a PAHU, so basically the node line is only consist of airflow set at the PAHU fan. What should i do regarding this matter?

Thanks.

User avatar
farahghanem
VE Professor
VE Professor
Posts: 147
Joined: Tue Sep 08, 2015 8:41 am
Location: Abu Dhabi
Contact:

Re: Flow overspecified at HVAC node.

Postby farahghanem » Sun Jul 10, 2016 7:06 am

can you provide screenshot of your system?
Image


Return to “ApacheSim”

Who is online

Users browsing this forum: No registered users and 3 guests