[Bldg-sim] effective R-value cavity insulation

Chris Balbach cbalbach at psdconsulting.com
Mon Jun 7 08:01:01 PDT 2010

Kevin et al:
Not sure if this is what you are looking for, but at any rate it is a very
good resource to share...
The folks at ORNL have developed a pretty cool 'calculator' which determines
complex wall R-values using the 'Modified Zone" method described in the 2009
ASHRAE Handbook of Fundamentals: Chapter 27. It's very easy to use, and
generates 'clear wall' R-Values for a user defined 'sandwich'.  It also
provides a good visual as to how "clear wall" and vs. "whole wall" R-values
differ (for a particular 'hard coded WWR and user defined fabric
The calculator provides results for a limited set of various 'common'
configurations, and provides a good 'QA/QC" process if you choose to build
your own (spreadsheet based?) tool to expand it's capabilities 

Here's the link:
There's also a 'tease' on this page
suggesting the folks at ORNL have plans "in the works" to assist analysts
with developing fabric descriptions:
New Features Include: Generation of Input Files for Whole Building Energy
Simulation Programs (in development) 
Have fun!
Chris Balbach, PE, CEM, BEMP, CMVP
Vice President of Research and Development
Performance Systems Development of NY, LLC
124 Brindley Street, Suite 4, Ithaca, NY 14850
ph: (607)-327-1647

From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Bishop, Bill
Sent: Monday, June 07, 2010 8:51 AM
To: Kevin Kyte; bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] effective R-value cavity insulation

One reference for calculating U-Factors for wood-framed, metal-framed and
masonry walls is the 2009 ASHRAE Handbook - Fundamentals, Chapter 27. There
is a section on "Two-dimensional U-factor calculation", which describes the
parallel-path, isothermal-planes, zone and modified zone methods of
calculating overall heat transfer rates through wall assemblies. Earlier
versions of Fundamentals (2005, 2001 etc.) will also have some background
William Bishop, EIT, BEMP, LEEDR AP | Pathfinder Engineers & Architects LLP
Mechanical Engineer
134 South Fitzhugh Street
Rochester, NY 14608
T: (585) 325-6004 Ext. 114
F: (585) 325-6005
wbishop at pathfinder-ea.com
P Sustainability - less is more.

From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Kevin Kyte
Sent: Saturday, June 05, 2010 12:13 PM
To: bldg-sim at lists.onebuilding.org
Subject: [Bldg-sim] effective R-value cavity insulation
I am curious what the relationship is between cavity depth, rated
insulation, and effective insulation in framed walls.  I am referencing the
ASHRAE 90.1 doc because it is really the only one I have on this subject.  I
have charted Table A9.2B and a logarithmic trendline appears to be a good
fit for extrapolating.  If anyone in academia, industry, or the societies
has more information on this subject I would certainly be grateful to
receive a good lead.  Thank you.
Kevin Kyte, LEED R AP
Watts Architecture & Engineering, P.C.
95 Perry Street, Suite 300
Buffalo, NY  14203
p:  716.206.5174
f.:  716.206.5199
e:   kkyte at watts-ae.com
http://www.watts-ae.com <http://www.watts-ae.com/> 
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