[Bldg-sim] IES-VE Energy

Karen Walkerman kwalkerman at gmail.com
Wed Feb 25 15:05:50 PST 2009


Varkie,

I disagree with your statement that eQuest is not appropriate for large
buildings because you can't change space names to match architectural names
in wizard mode, and the inputs created from the wizard aren't appropriate
for all spaces.  The wizards are called "Schematic Design Wizard" and
"Design Development Wizard" for a reason.  They aren't desinged for detail,
they're designed to help you make big design decisions quickly.  If you want
the building to be modeled as closely as possible to the final design, this
takes some extra work.  Yeah, re-naming spaces is a pain, but at 5 seconds
per space, re-naming 1,000 spaces takes about 1.5 hours, well worth the
effort.  If you re-name zones too, maybe it's 3 hours total.

Yeah, some things about eQuest are clumsy, like why does it create one
underground wall (and floor) consturction for each surface, when only 4-5
are needed for the whole model?  Why does it re-create occupancy, lighting
and micellaneous equipment schedules for each shell, even if the use is the
same?  And why does it create tons of duplicate infiltration schedules?
BUT... this takes an hour or two to clean up, and then you have a decently
flexible model that gives you reasonable results in a matter of minutes.
Versus a program that takes 1-2 hours to run.  I've done a few LEED projects
in Trace700 and it's painful modeling a design case and four (rotated) base
cases at 1-2 hours each, especially if you then find you've left anything
out.

I definitely agree that there are some major things missing in all modeling
programs, which is why I'm putting together a "Master Wish List" of
modeler's desires.  If you have things that you would like to be able to
model, things you'd like to be able to model more easily, or things that you
can do that you feel are very important, please send me your list.  I
currently have contact info for about 10 people representing various
simulation programs who want to know what we want!  Now's our chance to have
some input!

--
Karen



On Wed, Feb 25, 2009 at 2:15 PM, Varkie C Thomas <thomasv at iit.edu> wrote:

> Graham,
>
> The comment below stands out which might also be the reason for not using
> EnergyPlus on large projects.
>
> - DOE-2.2 runs much quicker.  For comparable 30,000 m2 buildings I would
> say DOE-2 runs in 1 minute and IES VE with an APhvac network probably 1-2
> hours.  If you through in Macroflo it probably adds another hour of
> simulation time.  As a result *iterative trial and error debugging* has to
> be done on a 1-2 week period.
>
> Large building projects (1 to 10 million sqft) with up to 1,000 zones and
> 70 systems ranging in size from 10,000 to 200,000 cfm (pardon the English
> units - the USA & the Bahamas are not going to switch to metric) require
> several iterative runs to get the input errors fixed.  Breaking up the
> project into small pieces is not a solution since it affects demand costs,
> central plants and other components.  I have worked on such projects using
> DOE2.1E and TRACE600/700.
>
> eQUEST is not suitable for such projects either.  One of its limitations is
> that you cannot enter the space names shown on architectural drawings.
> Others include assuming all the input data and making all the decisions for
> you when you enter the type of building.  1000 zones means 1000 infiltration
> schedules and multiples of other building components. It is unrealistic to
> check all the input created by eQUEST for errors. Fixing everything to match
> the exact project data has to be done in detailed edit.  Detailed edit means
> you lose access to the graphical method of creating the building model from
> AutoCAD drawings which is the main benefit of this program.
> Varkie
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.onebuilding.org/pipermail/bldg-sim-onebuilding.org/attachments/20090225/c60ddaf9/attachment-0001.htm>


More information about the Bldg-sim mailing list