Hi. Iam new to the list and have been enjoying the discussion. Re:
conductivity of mass.
As I understand the process, conductivity does not affect how much heat is
stored in mass. It would, however affect the RATE at which heat flowed
into or out of the mass. This might be important on clear days in
buildings with high solar savings fractions. Higher conductivity would
tend to reduce overheated air temperatures. Materials with low
conductivity would absorb heat more slowly, and the the air in the space
would have to hold more heat for a longer time. In spaces with high
conductivity (low R) windows, some of this excess heat in the air would
then be lost to the outside.
Another place where the issue comes into play is with a thermal storage
wall, where one wants maximun absorptance at the maximum rate to avoid
losing too much heat back out the glass. This is often achieved, however,
by some selecetive high absorptance coating or finish.
Mark DeKay
Assistant Professor of Architecture
School of Architecture
Washington University
One Brookings Drive
campus box 1079
St. Louis, MO 63130 USA
dekay@arch.wustl.edu
Office: 201 Givens Hall
314.935.6282, 314.935.8520 (fax)
__________________________________________________________________
This greenbuilding dialogue is sponsored by Oikos (www.oikos.com)
and Environmental Building News (www.ebuild.com). For instructions
send e-mail to greenbuilding-request@crest.org.
__________________________________________________________________