[Bldg-sim] LEED modeling / air leakage / R-values

[Cheney]

Hi Paul,

Probably I did not really understand your question. But my understanding is
that R values of building assemblies will be mainly used for conductive
calculation while air leakage rate through assemblies will be involved in
convective one. In this case, there is no modulated result reflected the
combined effect of the two parameters. Instead, they are represented
respectively in the simulation results.

Cheers,
Cheney
On Wed, Oct 13, 2010 at 2:31 PM, Paul Grahovac <paul.grahovac at prosoco.com>wrote:

>  I am not a modeler, but I’ve worked a bit with the TRANE Trace demo
> software a few years ago.
>
>
>
> I’ve forgotten how to maneuver within it, so I was hoping someone might
> comment on this question.
>
>
>
> The software provided an air leakage rate for whatever wall assembly is
> entered into the model.
>
>
>
> I know from previous posts and responses that you do not change the air
> leakage rate to account for any air barrier system that is to be installed.
> I also know that if you do apply an air barrier leakage rate, the model is
> very sensitive to it, and the model produces significant energy savings
> because of it.
>
>
>
> And, it’s my understanding the R-value rating of the insulation is used
> despite that the rating is based on more or less zero air flow.
>
>
>
> So, I’m wondering if the models, seeing both zero-air-flow insulation and
> un-moderated leakage rates, ignore one or the other or somehow produce a
> modulated result that reflects reduced wall assembly R-value from air
> leakage through it.
>
>
>
> Paul Grahovac, LEED AP
>
> Product Manager
>
> R-GUARD Air & Water-Resistive Barrier
>
> PROSOCO, Inc.
>
> 3741 Greenway Circle
>
> Lawrence, Kansas  66046
>
> (785) 830-7355
>
> (888) 376-3417 fax
>
> pgrahovac at prosoco.com
>
> web site  http://www.prosoco.com/
>
>
>
>
>
>
>
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