[TRNSYS-users] Floor vs Ceiling when both active?

Wed Dec 18 13:47:57 PST 2013

Hi David,

Thanks for getting back to me! I knew about the surface numbers, but sadly those didn't help, even at the airnode window level. In the airnode window, when the ceiling and floor are both boundary constructions with the same other-side condition, they appear to be identical in every way - barring surface number - so there's nothing extra to specify which number is the ceiling!

I solved the problem by exporting the BUI back into TRNSYS3D, and assigning the ceilings as boundary constructions with T_UP as the other-side temp and the floors with T_DOWN as the other-side temp. Upon reimporting into TRNBUILD I was able to use this as a distinguishing characteristic.

Appreciate your help.

Ajit Naik
Energy Engineer
dbHMS
303 W Erie Street, Suite 510
Chicago, IL 60654
p (312) 915-0557 x308
f  (312) 915-0558
www.dbhms.com

From: David BRADLEY [mailto:d.bradley at tess-inc.com]
Sent: Wednesday, December 18, 2013 3:23 PM
To: TRNSYS users mailing list at the Solar Energy Lab, UW-Madison; Ajit Naik
Subject: Re: [TRNSYS-users] Floor vs Ceiling when both active?

Ajit,
  Got it. I thought for some reason that your two surfaces were back-to-back and made up a ceiling of one zone and the floor of the one above, not a floor and a ceiling in the same airnode.

  In any case, if you look in the airnode window and click on each of your "walls" you'll notice that there is a number listed in blue to the right of the "geosurf" field. This is a surface number indicator. When you then go into the output manager, and start selecting your surfaces, you'll notice those same numbers listed.
Best,
 David

On 12/18/2013 14:49, Ajit Naik wrote:
Thanks David. I think I need a bit of clarification though:

I am just modeling the one airnode representing my level (call it level 5), and presuming that the imaginary levels 6 and 4 are at a constant temp by designating both the floor and ceiling of floor 5 as boundary constructions. There are no actual adjacent airnodes representing level 6 or 4 present. However, I still wish to consider the effect of level 4's radiant system on level 5 via the floor in addition to the effect of level 5's radiant ceiling. When trying to distinguish the floor from the ceiling here, I run into trouble.

I thought about creating ideally conditioned "dummy" airnodes for levels 6 & 4 and defining the radiant surfaces as adjacent constructions to overcome this, but wanted to know if there's an easier method of telling floor from ceiling with the model as-is.

Thanks again!

Ajit Naik
Energy Engineer
dbHMS
303 W Erie Street, Suite 510
Chicago, IL 60654
p (312) 915-0557 x308
f  (312) 915-0558
www.dbhms.com

From: trnsys-users-bounces at cae.wisc.edu<mailto:trnsys-users-bounces at cae.wisc.edu> [mailto:trnsys-users-bounces at cae.wisc.edu] On Behalf Of David BRADLEY
Sent: Wednesday, December 18, 2013 12:11 PM
To: TRNSYS users mailing list at the Solar Energy Lab, UW-Madison
Subject: Re: [TRNSYS-users] Floor vs Ceiling when both active?

Ajit,
  I would have defined a single construction separating the airnode above from the airnode below (instead of defining two BOUNDARY surfaces). To get the surface temperature of the ceiling side of the construction, select the airnode that contains the ceiling when you are in the TRNBuild output manager. Change to "surface outputs" and select the TSI ntype (ntype17).
Best,
 David

On 12/18/2013 11:25, Ajit Naik wrote:
Hello All,

I am modeling a single floor of multi-story building with an in-ceiling radiant system. I have defined an active surface has a carpet on the "floor" side and exposed concrete on the "ceiling" side.

I naturally defined the ceiling of the airnode as an active surface, but also defined the floor as an active surface as well to account for the effects of the underlying level's radiant ceiling. Both the ceiling and the floor of the airnode are defined as boundary surfaces with a fixed temperature on the other side.

Here's my problem - I am interested in recording the airnode's CEILING temperature (at the exposed concrete surface) - but within TRNBUILD the ceiling and floor both have identical surface areas and I cannot tell which is which! The only differentiable marker I observe is the surface type. Is there any simple way to find which of the two surfaces is the Ceiling in this case?

Thank you!!

Ajit

Ajit Naik
Energy Engineer
dbHMS
303 W Erie Street, Suite 510
Chicago, IL 60654
p (312) 915-0557 x308
f  (312) 915-0558
www.dbhms.com

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***************************

David BRADLEY

Principal

Thermal Energy Systems Specialists, LLC

22 North Carroll Street - suite 370

Madison, WI  53703 USA

P:+1.608.274.2577

F:+1.608.278.1475

d.bradley at tess-inc.com<mailto:d.bradley at tess-inc.com>

http://www.tess-inc.com

http://www.trnsys.com
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