Big Green: TRANE/TRACE Oversizing Equipment?

[Ralph Bicknese]

Russ:

I'll have to give a short answer hear due to time constraints. I believe
Trane Tracer is an acceptable energy simulation program

I have checked with an outside energy modeler.  They are comfortable with
the results they get from Trane Tracer. 

Secondly, they posed your question to Trane (without using your name). Trane
defended their program as one would expect but I also have no reason to
doubt this.

Third, a LEED requirement for energy simulations is that ASHRAE 90.1-2004
Appendix G Performance Rating Method stipulates calculations be done "using
an approved simulation program". The approved programs have to undergo
fairly stringent analysis to fall within reasonable accuracy guidelines. As
long as Trane Tracer is an approved system (which I believe it is) then IF
the input is correct, then the results should be within accepted tolerances.


But as has been said, "Garbage in, garbage out". The inverse is, as long as
the input is good, the results should be good. These programs are quite
complex and it is not uncommon for some big errors to be made on inputs and
for them to be difficult to find.

I understand that Trane offers free (included review) of the results to
those who have purchased the program. An extra set of eyes for review is a
good idea.

Cheers,
Ralph

Ralph Bicknese, AIA, LEED AP
hellmuth + bicknese architects
7211 manchester rd.
st. louis, mo 63143
t: 314.531.9901
f: 314.531.9902
c: 314.265.0517
www.rbicknese at hellmuth-bicknese.com
www.hellmuthbicknese.com

h+b is a member of the US Green Building Council and the American Institute
of Architects

 

-----Original Message-----
From: biggreen-bounces at lists.biggreen.org
[mailto:biggreen-bounces at lists.biggreen.org] On Behalf Of Russ Weiser (HKP)
Sent: Tuesday, March 18, 2008 12:21 PM
To: biggreen at lists.biggreen.org
Subject: Big Green: TRANE/TRACE Oversizing Equipment?

At a recent workshop on energy modelling one of the speakers had the 
opinion that TRANE/TRACE simulation software tended to oversize the 
mechanical equipment (sometimes by double).  I've also heard this 
from one of the Mechanical Engineers we work with for one case study.

As architects we'd like to help design energy efficient buildings and 
save up-front cost by "right-sizing" the mechanical equipment.  If 
it's "twice-sized" it takes away one of the benefits of energy 
efficient design.  Has anyone else had experience with TRANE/TRACE 
oversizing mechanicals?


Russ Weiser, AIA, LEED AP, Ph.D.
HKP architects
314 Pine Street, Suite 205
Mount Vernon, WA  98273
(360) 336-2155
(360) 336-3657 FAX
rweiser at hkpa.com
http://www.hkpa.com


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