[BLDG-SIM] Materials properties for simulation
Chip Barnaby
cbarnaby at wrightsoft.com
Wed Nov 12 07:25:37 PST 2003
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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