[Bldg-sim] Trace 700 vs eQuest

Fri Jan 11 06:52:21 PST 2008

As a post script, I have found Trace to run rather/very quickly as well - even for large buildings with complex systems as Kevin indicates below.  
I think the key is to make sure you are maximizing the use of Trace's templates.
Trace's use of templates is a very nice feature and seems to be a potential benefit over Equest (although, I'm just a beginning Equest user).  
Each energy modeling program seems to have its own pros and cons, though, with no one program being all things to all people on all projects.
Julia

----- Original Message ----
From: "Wyman, Kevin L UTPWR" <kevin.wyman at utcpower.com>
To: Randy Wilkinson <randy at hvacware.net>; Sherie E. Hensley <shensley at chpengr.com>
Cc: bldg-sim at lists.onebuilding.org
Sent: Friday, January 11, 2008 8:16:41 AM
Subject: Re: [Bldg-sim] Trace 700 vs eQuest

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
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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