[BLDG-SIM] Increased R value Credit for Concrete and Themal Massing

[Curtis Pedersen]

Dave:

This concept falls into the "cheater" category.  What happens is that 
the proponents of heavy construction elements show that the steady 
periodic behavior of a heavy structure, at some well-selected 
frequency, is better than the behavior at steady state.  The electrical 
analogy would be to replace resistance with capacitive impedance.  Of 
course it depends on the frequency, and it is not resistance, so the 
steady state (zero frequency) result will be different.

A reasonable building simulation tool properly accounts for both the 
capacitance and the resistance of a building element.  The "effective 
R" is bogus.

Curtis Pedersen
Professor Emeritus of Mechanical Engineering
University of Illinois



On Tuesday, December 2, 2003, at 11:26 AM, David Stewart wrote:

> Dear Folks
>  
> Has anyone explored the increased R value credits for thermal massing 
> for example Dow T-Mass etc. and can one simply increase the R value to 
> the 'effective R value while changing the mass in DOE.  I would like 
> some more background on this credit with 3rd party validation
>  
> Thanks
>  
> Dave Stewart
>  
> David C. Stewart & Associates Inc.
> 16 Shawinigan Road
> Dartmouth, NS B2W 3A3
>  
> Website: http://dcsa.ca
>  
> Tel: 902 462 8111
> Fax 902 435 6646
> <David C Stewart MS P. Eng..vcf>
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