[Trace-users] How long it takes for energy modeling?

Fri Apr 3 04:15:21 PDT 2009

As stated below, times vary depending on all items noted. When asked by
department heads or project managers I usually respond with 40 hours.
Preliminary results for an early phase model can be completed in 4 to 8
hours. Appendix G with full documentation probably 60 hours plus. If you
are trying to match utility bills it could take even longer unless you
get lucky. The simpler the model the faster run time and budget time.

Hope this helps.

Robert Vogt
Mechanical Group, LEED Accredited Professional
Luckett & Farley
      [smart design]
737 South Third Street
Louisville, Kentucky 40202
502-585-4181 x105
502-587-0488 Fax
Bvogt at luckett-farley.com
www.luckett-farley.com
Founded 1853

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Today's Topics:

   1. How long it takes for energy modeling?  HME (Sherie E. Hensley)
   2. Re: How long it takes for energy modeling?  HME (John Mathews)

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Message: 1
Date: Wed, 1 Apr 2009 12:46:48 -0500
From: "Sherie E. Hensley" <shensley at chpengr.com>
Subject: [Trace-users] How long it takes for energy modeling?  HME
To: <trace-users at lists.onebuilding.org>
Message-ID:

<405C8A3ED8EB824983B835EB43C2828102DD3B78 at s-chp-hou-mail.chpengr.net>
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I have done several energy models over the last few years using Trane
Trace.  I have heard others (typically from those who don't have
experience with energy modeling) say "it only takes a day" to create an
energy model and get results.  

I am trying to get a better understanding of how long it takes others to
complete an energy model.  I realize there are many factors involved and
length of time can vary drastically given the complexity of the project.

For an xxx sq ft project with xxx systems:

1.  What phase are you starting the energy model - SD, DD, CD?

2.  What information are you starting with - load results from another
program, rules of thumb for system sizing, etc?

3.  What program are you using?

4.  How long does it take to build the proposed model?

5.  How long does it take to build the baseline model (per ASHRAE
90.1-2004, Appendix G)?

6.  How long does it take to calculate the results from the energy
simulation program?

7.  If you have started a projected in the SD phase, how detailed is the
input information you use?  How do the results compare to the energy
model developed in CD - within 10%?

Any information you can provide would be helpful.

Thanks,

Sherie Hensley

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Message: 2
Date: Wed, 1 Apr 2009 14:49:18 -0400
From: "John Mathews" <jmathews at acg-pa.com>
Subject: Re: [Trace-users] How long it takes for energy modeling?  HME
To: <trace-users at lists.onebuilding.org>
Message-ID: <01c601c9b2fa$9070a7c0$b151f740$@com>
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1.  In my perfect world preliminary energy models get built during SD
phase to assist the entire team with design decisions.  What I normally
encounter is either a model done after the building design is set but
the MEP systems are still in flux or worse projects that were completing
CDs and decide they need to run energy models to get LEED certification.

2.  I think the complexity of the model depends on the stage of a
project.
Models started in SD are usually very generic and not very details.  As
the design progresses so does the detail of the model.

3.  I use Trane Trace

4. It depends on the stage of the project it is started in and how much
duplication of spaces can occur for a large building.

5.  I have found that the baseline model can be built very quickly as
long as you already have library members that cover the ASHRAE
standards.

6.  I have had run times of several minutes to several hours depending
on the size of the building and whether or not full year weather is
required.
I have found out that Trace runs 5 to 7 times slower when using full
year weather.  Because of this when doing LEED models I use part-year
weather data until I get to the end and start working on data that will
be sent to USGBC.

7.   I use basic information, overall square footages, window
percentages,
etc and the same type of generic information for the building systems as
well.  I have had it vary wildly, but this is a function of models that
start in SD phase have a lot of stuff change between the initial SD
models and the final models.

Thanks,

John Mathews, PE, LEED AP

Senior Mechanical Engineer

Project Manager

Apogee Consulting Group, PA

http://www.acg-pa.com <http://www.acg-pa.com/> 

From: trace-users-bounces at lists.onebuilding.org
[mailto:trace-users-bounces at lists.onebuilding.org] On Behalf Of Sherie
E.
Hensley
Sent: Wednesday, April 01, 2009 1:47 PM
To: trace-users at lists.onebuilding.org
Subject: [Trace-users] How long it takes for energy modeling? HME

I have done several energy models over the last few years using Trane
Trace.
I have heard others (typically from those who don't have experience with
energy modeling) say "it only takes a day" to create an energy model and
get results.  