[Bldg-sim] Trace 700 vs eQuest

Fri Jan 11 05:16:41 PST 2008

As a former Trace user and an aspiring eQuest user, I would echo Randy's
insight. The paid technical support is fantastic with Trace. I would
send emails to CDSHelp and usually get a response within an hour. While
not perfect, the Trace program is comprehensive and actively updated.
With the new Trace Wizard tool, one can building simple models very fast
(although in order to access this functionality, the initial dialog box
must be closed and the File, New and then select the Wizard ... this is
not intuitive). I also have found great use for the Chiller Plant
Analysis tool that allows me to focus on the central plant if I already
have loads.

I suspect that the price of eQuest is a big reason many architects are
"using" eQuest. My experience with energy modeling is that it really
takes detailed inputs to get it right. I typically work on existing
buildings so I need to calibrate with the energy bills. I try to break
the model down by control zones (i.e. if a controller operates the HVAC
system on 3 rooms then those become one zone and the level of detail I
go to from an architectural standpoint. Sometimes this requires room by
room analysis and sometimes I can aggregate these control zones together
if the control and exposures are identical). This often requires a lot
of paper and highlighters to accomplish well. 

Having said that, if I want to decide on system X versus system Y, I can
use the Wizard function of Trace to develop a block building, pull in a
sample utility rate, and determine my systems and total energy use
really quickly. It is not 8760 but gets me similar results to a quick
eQuest run. I do like the 3D building model that eQuest develops as a
visual check of the envelope input. It is really useful.

In the end, the experience of the user with the tool is more important
than which tool is actually used. Over time one learns the work arounds
of the limitations of all tools or uses a different tool for different
modeling scenarios. 

I would suggest trying the Wizard. Learning eQuest in your spare time
and asking the architects to send you the file of the building so that
you can import it from AutoCAD into Trace. Building modeling is a bit of
a slog but once the basic model is built (keeping the end goal of energy
analysis in mind through effective zoning or grouping of systems and
control points), the resultant alternatives can be developed rather
quickly. 

I am not sure how large of a system you have that takes 5 hours to run.
I have run a 250,000 square foot high school with 14 VAV systems, 6 H&V
systems, a central plant on 8760 and the run is around 15 minutes (maybe
its time to ask your boss to upgrade that old 386).

Kevin

________________________________

From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Randy
Wilkinson
Sent: Thursday, January 10, 2008 4:18 PM
To: Sherie E. Hensley
Cc: bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] Trace 700 vs eQuest

Sherie and all,

Where I work, we also have been using Trace for decades.  I've used
Trace, HAP, and eQuest. for years now.  Here is my take:

eQuest:

*	Great for quick energy models where room-by-room breakdown of
loads and energy use is not required.  

*	Not very useful for load calculations.  This is what the eQuest
training class taught me.  Something about peak load calculations not
appropriate (weather data?).  I wish they could fix that.  I'd be
tempted to use eQuest for load calculations.

*	Determine energy impact of improvement measures quickly. 
*	Energy use reports are pretty and impress everyone. 
*	Like Brandon said, the 3D views of the building geometry is
useful for checking. 
*	Support is best gotten from this mailing list.  Sometimes
questions go unanswered. 
*	The two wizards to get your model mostly done.

*	Free!

Trace:

*	Proven and reliable for loads AND energy study work.

*	Able to do more detailed zone and room breakdown of load
components.  

*	Output reports seem to be tailored specifically for load
calculation and work well for that purpose. 
*	Energy and load output reports are not pretty, but the
experienced users like them. 
*	The professional support technicians at Trane are excellent and
you can get answers fast.

*	Must start your model from scratch every time (although we hear
they are working on a wizard)

*	Costs a lot of $$$

When we do HVAC design work in conjunction with energy study work, the
Project Engineer always wants to use Trace for the energy model.  He
will say that because he already has a Trace model and all we need to do
is add schedules and energy rates.  It has been my experience that when
you have a building model detailed enough for load calculations, it is
WAY too detailed for energy modeling.  The Trace energy calculations
take too long and are not really more accurate.

5 hours for results on energy modeling is outrageous.  Sounds like a
loads model is being used for energy modeling.  Time to re-think.  Even
my large eQuest models only take a few minutes to simulate.

Randy

-- 
Randall C. Wilkinson , P.E., C.E.M., LEED A.P., Mechanical Engineer 
v:509.747.2179  f:509.747.2186  i:www.lseng.com <http://www.lseng.com> 
L&S  Engineering Associates, Inc.

Sherie E. Hensley wrote: 

	My company has used Trace for many years with the main purpose
to calculate loads.  Trace has continued to evolve.  However, with the
evolution the program has become more and more detailed for input.
Additionally, the time it takes to calculate results alone can be
extremely lengthy (5+ hours with full year weather data).  Now that the
need for energy modeling especially for LEED has dramatically increased,
I am currently modeling several projects using Trace.  In talking with a
few architects and even a third party energy modeler, they are using
eQuest.  

	I realize there is a learning curve for energy modeling as well
as new software.  However, my company is looking for an energy modeling
program that allows for straight forward input and reliable/accurate
results.

	I have downloaded eQuest and spent a few hours looking at the
program and capabilities.  At first glance eQuest appears to not be as
detailed in its inputs.

	Does anyone have any experience with Trace and eQuest?  Pros vs
Cons for energy modeling?

	Thanks in advance,

	Sherie Hensley P.E., LEED AP
	Mechanical Engineer

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