[BLDG-SIM] Materials properties for simulation

[D. Charlie Curcija]

Hi Chip,

	For windows related thermo-physical properties of materials, NFRC has
conducted small research project at Umass to research different sources,
including existing values used at NFRC, and to publish consolidated and
referenced properties.  In this project we have used variety of sources, and
we have compiled relatively large list, which was published in NFRC 101
(available for download from www.nfrc.org).  We thought that out of all of
references, the best single and updated source on thermophysical properties
of building materials was European Commission sponsored study (Anderson et.
al. 1999.  "Analysis, selection and Statistical Treatment of Thermal
Properties of Building Materials for the Preparation of Harmonised Design
Values").  The data was well documented and properly sorted with recommended
values at the end.  We used quite a bit from that source for NFRC project.
If you would like, I can send you a copy of this report.

I find that using sources like Toulukian with several hundred entries for
each typical material is equivalent to starting a major research project and
is therefore probably impractical (unless of course you have very specific
material subjected to a large range of temperatures).

One other note. ASHRAE has funded research project through TC 4.4 to
document and update thermophysical properties of building materials, but to
my knowledge that was never completed due to the default from a PI.

Regards,
Charlie Curcija

-----Original Message-----
From: postman at gard.com [mailto:postman at gard.com]On Behalf Of Chip
Barnaby
Sent: Wednesday, November 12, 2003 10:26 AM
To: BLDG-SIM at gard.com
Subject: [BLDG-SIM] Materials properties for simulation


Dear all --

I am working on ASHRAE 1199-RP, "Updating the ASHRAE/ACCA Residential Loads
Calculation Procedures and Data".

The revised method under development is based on a 24 hour design-day
simulation using a heat balance model.

In order to fully "package" the method for end use, thermal properties
values must be selected for a moderately inclusive set of construction
materials.

There is often disagreement among all the common sources for materials
properties (ASHRAE HOF tables, standard values built into simulation
programs etc.).

For example, the specific heat of gypsum wall board is given as 1.09
kJ/kg-K (0.26 Btu/lb-F) in ASHRAE 2001 HOF Chapter 25, Table 4 (and several
other sources that I've found that cite ASHRAE).  There is no source given
for this value (unless I'm missing something).  Meanwhile, the California
Energy Commission has selected 0.837 kJ/kg-K (0.20 Btu/lb-F) as their
standard value for compliance simulations, again without documentation.

For 1199-RP, I would like to resolve at least the glaring
discrepancies.  Beyond that, it would help the field if we could work
toward a set of documented consensus values for common use.

Can anyone point me to authoritative sources for info that you have found
helpful?

Chip Barnaby


---------------------------------------------------------
Chip Barnaby                   cbarnaby at wrightsoft.com
Vice President of Research
Wrightsoft Corp.               781-862-8719 x118 voice
394 Lowell St, Suite 12        781-861-2058 fax
Lexington, MA 02420            www.wrightsoft.com
---------------------------------------------------------

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