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

Ajit Naik anaik at dbhms.com
Wed Dec 18 12:49:10 PST 2013

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
303 W Erie Street, Suite 510
Chicago, IL 60654
p (312) 915-0557 x308
f  (312) 915-0558

From: 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?

  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).

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 Naik
Energy Engineer
303 W Erie Street, Suite 510
Chicago, IL 60654
p (312) 915-0557 x308
f  (312) 915-0558


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