[Bldg-sim] Balcony Heat Loss

Brian Fountain bfountain at greensim.com
Fri Jun 17 07:39:04 PDT 2011


The accepted workaround is to add another wall type that is comprised of 
12" of just concrete (U = 5.5 W/sq-m C) and has a height equal to your 
slab thickness -- say 6".  So the area would be the wall length x the 
slab thickness.

Not sure if this is clear -- it is better described on page 7-9 of the 
EE4 modelling guide.

Brian

On 6/17/2011 10:20 AM, Aaron Smith wrote:
>
> Hello,
>
> When performing energy modeling to determine compliance with the 
> Canadian Energy Code (MNECB), penetrations through the building 
> envelope must be taken into account when calculating wall R-values if 
> their area exceeds 2% of envelope area.  I'm working on a LEED project 
> and trying to calculate the wall R-value of a Hotel taking into 
> account heat losses from the balconies which are extensions of the 
> floor slab (balcony penetrations exceed 2% of envelope area).
>
> I realize this is a rather complex heat transfer problem but hope 
> there may be an easy approximation.  My first thought was to treat 
> them like a parallel path heat transfer problem: 1/Req = %slab/Rslab + 
> %wall/Rwall but I'm thinking that may not be fair (perhaps this would 
> be used if you had concrete studs in the wall).  My other thought is 
> to treat the slab penetrations as a separate wall type (uninsulated 
> concrete wall) -- this would have a reduced affect on the overall wall 
> R-value.
>
> Does anyone have thoughts on this?
>
> Thanks,
>
> Aaron
>
> **Aaron Smith, **//P.Eng //
>
> /LEED® AP BD+C,//M-ASHRAE, Mechanical Engineer/
>
> t: (902) 422-7393
>
> f: (902) 423-4945
>
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