No subject

(cold winter) climates, I have seen where a heating dominated building =3D =
heating dominated climate; has been turned into a cooling dominated =
building because of over-design with energy conserving strategies (ie too =
high of R-values and use of heat recovery), in addition to ignoring the =
type of occupancy and/or the hours of operation of the building.  I =
understand that this doesn't help you directly, but I wanted to support =
Mitchell's comments about fully knowing your building and it's occupancy =
in order to understand why you might be seeing your energy results go in =
the opposite direction of what you would initally expect.

Also you might find that using high performance glazing such as the values =
you are proposing (might I assume this is a Visionwall or heat mirror =
glazing assembly performance) are truly more beneficial in eliminating the =
need (and Capital cost) of installing a perimeter heating system.  The =
reason being, with this high R-value performance of the glazing system, =
you have neutralized the skin losses, and the situation may actually =
become more of a thermal comfort issue, rather than an energy conserving =
issue.  I had this exact thing happen when trying to apply and model the =
Visionwall 4-element (triple-pane equivalent) glazing system to a =
University building in Winnepeg, Manitoba.  The true benefit of the =
application of the U =3D 0.19 performance value I was modelling was not in =
the energy savings, but in the lack of need to install a perimeter heating =
system, ultimately saving the project over $90,000 capital cost and =
resulting in less than a 1 year payback for the University.  The short =
payback was associated more with the offset of capital cost, rather than =
the energy cost savings for the high performance glazing.

Hope this gives you more ideas to think about.

cheers,

Pasha Korber
Associate
LEED Accredited Professional

Stantec Consulting
2742 17th Street
San Francisco, CA 94110
Phone: 415-626-6864
Direct:  415-706-9518
Fax:      415-626-1268
pkorber at stantec.com

stantec.com

>>> Mitchell Dec <mdec at glumac.com> 12/15/05 1:27 PM >>>
When using a "high performance glazing" you need to be careful.  Every
building has a different signature (i.e. different shape, size, occupancy,
climate, etc.)  Therefore, one should be careful to say a "high performance=
"
glazing is better than a lesser performance glazing.  It is best to model =
a
wide range of u-values such that you can see which glazing is optimal for
the specific building.  Often, one will see that a manufacturer says it is
"high performance" which it is on its own.  But, couple that with your =
wall
insulation and the "high performance" wall configuration requires a
different u-value.
=20
You will see a point of diminishing return and in many cases a point at
which the lower window u-value coupled with your wall insulation will in
fact cause one load to go up and the other to go down or vice versa,
depending on your climate.  This is also similar in determining when you
have too much or too little insulation.  What "high performance" glazings =
do
is allow an opportunity to determine what the most cost effective path is,
decreased window u-value or increased wall insulation.  Therefore, one is
able to have several optimization paths.
=20
I find it convenient to produce a graphical representation (excel is =
pretty
easy for this) to graph the variable versus the desired output (energy =
used
or dollars saved, if a LEED project).
=20
I hope this helps.
=20
-Mitch
=20

 <?xml:namespace prefix =3D o ns =3D "urn:schemas-microsoft-com:office:offi=
ce"
/>

Mitchell J. Dec
Energy Analyst=20
503.345.6283 | mdec at glumac.com <mailto:mdec at glumac.com> =20

 <http://www.glumac.com/>=20

  _____ =20

320 SW Washington, Suite 200
Portland, OR 97204-2640
T.  503.227.5280  F. 503.274.7674

Thinking. Inside the building.
http://www.glumac.com/ <http://www.glumac.com/> =20

-----Original Message-----
From: Zoeteman, Mark R. [mailto:mrzoeteman at FTCH.com]
Sent: Thursday, December 15, 2005 12:53 PM
To: bldg-sim at gard.com
Subject: [bldg-sim] High Performance Glazing



I am modeling high performance glazing with U=3D0.14, SC=3D0.35 and =
comparing to
typical 1" thick insulating low-e glass with U=3D0.33, SC=3D0.76.  Climate =
is
midwest US and 86% of the glass is facing north. The north wall is =
basically
all glass and spandrel. Heating is suppied from district steam supply.

Results show increased steam energy consumption from February through
September with high performance glazing and less for remaining winter
months. HVAC system is VAV with hot water reheat coils.

Overall annual steam energy consumption reduction is very small. I =
expected
to see significant heating energy savings due to increased perimeter
R-value. Has anyone modeled high performance glazing and seen similar
results?=20


Mark Zoeteman=20
FTC&H, Inc.=20
(616) 464-3739=20
mrzoeteman at ftch.com=20




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