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Supply air and extract air in DesignBuilder

asked 2016-01-20 05:14:24 -0600


There are several buildings across the world where the supply air is set in one place and the extract air in another. In DesignBuilder Detailed HVAC, when defining zones, one has to put the supply air and extract air in the same zone. Therefore it is not possible to simulate the airflow from one room to another before beeing extracted.

Is there a way to do it?

Thanks in advance Regards,

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answered 2016-02-05 00:25:00 -0600

Dave's avatar

updated 2016-03-22 01:59:08 -0600

There is a "zone exhaust fan" in DesignBuilder which enables you to do this. More information is in the Help file here:

If you want to utilise heat recovery in an air loop you will need to model the system using a return plenum. There is information on using a plenum in the help file, but you essentially replace the return mixer on the air loop with the return plenum and assign your plenum zone (toilets, kitchen, corridor etc). This assumes all flow is back through the plenum object linked to your return air zone, so you don't need to introduce doors and return air grilles etc as you would using the zone exhaust fan.

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Hi Dave, Thanks for your answer. I'm already aware of that component on DesignBuilder. But it can't be linked to the main Air Loop. What happens here in Belgium, is that the extracted air returns to the Heat Recovery System located in the AHU. If I do as you said, I would lose free heating energy to the outside environement.

NassimJ's avatar NassimJ  ( 2016-02-05 09:54:41 -0600 )edit

Hi Nassim, the answer has been adjusted to take into account your need to use energy recovery.

Dave's avatar Dave  ( 2016-03-18 13:13:36 -0600 )edit

Hey, Thank you for your answer. I haven't thought about that option ( actually, I didn't know that it does exist). I will try it very soon. Thanks again for your input!

NassimJ's avatar NassimJ  ( 2016-03-22 05:06:16 -0600 )edit

Hi Nassim,

I'm facing the same problem (for Belgian Context): extracting in other zones with air transfer... Did you finally get a solution to model this? Thanks for your help!


OLI's avatar OLI  ( 2018-09-19 09:36:53 -0600 )edit

Hi all, I'm getting back on this old post. Is there any solution when the zone where air is extracted is also occupied and heated/cooled? If I assign that zone to the plenum, DB assumes no heating system there...

Thanks for your help!

MuV's avatar MuV  ( 2020-01-09 03:33:35 -0600 )edit

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Asked: 2016-01-20 05:14:24 -0600

Seen: 1,880 times

Last updated: Mar 22 '16