[Virtual-sim] [Bldg-sim] IES-VE Energy
wang95 at purdue.edu
wang95 at purdue.edu
Sat Feb 28 08:18:30 PST 2009
Dear Dr. Huang and Dr. Glicksman:
Yes, the work ended with up a program called CONTAM97R, which can do both onion
and ping-pong type of thermal-air couplings. The program has been used
internally for several projects related to natural/hybrid ventilation. We are
looking for the potential of extending its capability. Besides
Energyplus+Airnet, TRANSYS has a new type to couple with CONTAM too, which is
also under further development. By the way, we have a new version of CONTAM 3.0
with CFD capability, which is under beta testing. Hopefully, the new version
will be released publicly soon.
Thanks,
Leon
____________________________________
Liangzhu (Leon) Wang, PhD
lwang at nist.gov
Building Environment Division
National Institute of Standards and Technology
(301) 975-6447
100 Bureau Drive, Stop 8633
Gaithersburg, MD 20899-8633
____________________________________
Quoting Joe Huang <joe at drawbdl.com>:
> Leon,
>
> That's very interesting. I know Jim Axley also worked with George
> Walton a decade or so ago to add heat conduction routines to CONTAM in
> order to simultaneously solve for heat and mass transport. I don't know
> whatever became of that work, though.
> Univ. of Colorado is now working on an ASHRAE project 1456-RP to
> evaluate methods to model natural ventilation, although so far they've
> only looked into coupled techniques, not simultaneous solutions. Have
> you considered using an existing thermal program for the thermal side of
> the equations ? I know that would be major surgery, but then you will
> have access to all the
> effort that's already done in modeling heat transfer and radiation.
>
> Joe Huang
> White Box Technologies
> 346 Rheem Blvd. Suite 108D
> Moraga CA 94556
> phone 1 925 388 0265
>
> Leon Glicksman wrote:
> > We are working on a natural ventilation program, CoolVent, that does
> > zonal analysis for multiple zones such as multistory open plan zones
> > connected to a central atrium. It simultaneously solves the energy and
> > momentum equations for each zone and includes thermal mass effects for
> > transient simulations. It is still under development.
> > Leon Glicksman
> >
> > Leon R. Glicksman
> > Professor of Building Technology and Mechanical Engineering
> > Massachusetts Institute of Technology
> > Room 5-418
> > 77 Massachusetts Avenue Cambridge, MA 02139
> > phone: 1 617 253 2233
> > e-mail : glicks at mit.edu
> >
> >
> >
> > Joe Huang wrote:
> >> On the modeling of natural ventilation, I've not heard of anyone
> >> who's coupled thermal with CFD for annual simulations, and if they
> >> did I'd guess they're still waiting for the results! There are,
> >> however, several programs (EnergyPlus, ESPr) that do link up with a
> >> multi-zone air-flow network program (EnergyPlus uses AirNET/CONTAM)
> >> to "ping pong" with the thermal
> >> program. My experience doing an earlier linking of COMIS into
> >> EnergyPlus showed increases in runtimes of 2-3 times (that's on top
> >> of the standard run times most people have seen). I also saw
> >> instabilities in the "ping pong" approach that made me think of more
> >> iterations (horrors!), but the funding got cut so I didn't pursue that.
> >>
> >> As for eQuest handling of natural ventilation, its capabilities are
> >> probably the same as DOE-2.1E, which does have a very simple
> >> one-zone natural ventilation model that would calculate outside air
> >> flow rates based on that zone's leakage are, outside temperature, and
> >> wind speed. This capability was available first only in the RESYS
> >> system, but later extended to the other systems. I wouldn't use it to
> >> design a commercial building with hybrid ventilation, but for rough
> >> estimates of natural ventilation potentials for operable windows in
> >> perimeter offices, how bad is it ? Another nice thing about this
> >> natural ventilation feature in DOE-2 is that DOE-2 Systems first
> >> checks to see if NV can hold the setpoint temperature, and if not, it
> >> shuts off NV and turns on the mechanical system. Voila! The ideal
> >> natural ventilation control. I've yet to see such a control
> >> available in other programs.
> >>
> >> So, I get a little impatient when people talk about the capabilities
> >> of different programs in a yes-no context.
> >>
> >> Joe Huang
> >> White Box Technologies
> >>
> >>
> >> Karen Walkerman wrote:
> >>> Carol said most of it, and I definitely second the prohibitive cost
> >>> for a program like IES-VE for a small shop, but I've used Trace700,
> >>> which I assume uses an iterative algorithm (it took about 1-2 hours
> >>> run-time). So maybe using an iterative algorithm gives a little
> >>> more accuracy, I'd guess on the order of 2-5%, BUT many of these
> >>> programs don't allow you the flexibility in your inputs to take
> >>> advantage of the iterative nature of the program. For many systems,
> >>> you don't need to use an iterative program, you just need to know
> >>> the hourly space loads, hourly ventilation loads, and equipment
> >>> operation efficiencies at the given conditions. You need just a few
> >>> layers: component load (walls, windows, internal loads, etc), zone
> >>> loads, hvac system loads, loop loads and plant loads, in order to
> >>> get pretty good results. You need a few additional levels when your
> >>> systems get more compliated, but it doesn't require a
> >>> super-complicated algorithm.
> >>>
> >>> Bottom line is, many programs have their drawbacks. eQuest is not
> >>> good at modeling natural ventilation, precisely because it is not a
> >>> CFD program. If it were good at modeling natural ventilation, it
> >>> wouldn't be able to run in 1-2 minutes.
> >>>
> >>> I'd love to see a program that could integrate into two simulation
> >>> engines, one quick engine for trouble-shooting, doing DD models and
> >>> running lots of alternatives, and then an interative simulation
> >>> engine for more complex stuff, natural ventilation, complicated HVAC
> >>> system configurations, etc. Add that one to the wish-list! Maybe
> >>> we'll see it in 20 years.
> >>>
> >>>
> >>> --
> >>> Karen
> >>>
> >>> On 2/26/09, *Carol Gardner* <gems at spiritone.com
> >>> <mailto:gems at spiritone.com>> wrote:
> >>>
> >>> It can be better because you only have to do the renaming process
> >>> once and then your done whereas you are going to have to do the
> >>> rerunning way more than once: at least 4 orientation runs, a run
> >>> for each energy efficiency measure, a run each time you realize
> >>> you forgot to do the ____(fill it in). You are way further ahead
> >>> using eQUEST. I'm not sure what you mean by an interactive 3D
> >>> viewer, I find eQUEST's 3D views really helpful but I get the
> >>> impression you are talking about something else. At any rate, I
> >>> have used IESVE and E+ and I think they both excel in ways that
> >>> eQUEST doesn't but IESVE is just too expensive for a single shop
> >>> person like me and E+ is just too slow so far. I don't rule them
> >>> out for use when I'm rich and they're faster, though.
> >>>
> >>> Carol
> >>>
> >>> Paul Carey wrote:
> >>>
> >>>
> >>> Karen and all,
> >>>
> >>> I’m confused here....how can a program that takes up to 3
> >>> hours to rename the zones but then takes minutes to get
> >>> results, be better than something that takes a few minutes to
> >>> rename, but then takes a couple of hours to run? They are
> >>> about the same surely? The only advantage I can see is that
> >>> further iteration might be quicker in the former assuming your
> >>> geometry doesn’t change.
> >>>
> >>> I have been using various modelling tools such as IES VE, TAS
> >>> and DesignBuilder as well as a few other tools when necessary
> >>> (Fluent & CHAM CFD etc) since the late 90s. IES is good, it’s
> >>> quick to produce models and excellent for dynamic natural
> >>> ventilation design. TAS is better at the HVAC and natural
> >>> ventilation design aspects than IES and I think it’s more
> >>> accurate, but it’s front end still lacks some of the
> >>> functionality of other tools. Hopefully that is being
> >>> addressed by their links with Bentley. My colleague, Chris
> >>> Yates (also on this list) has become a bit of a wiz with the
> >>> sketchup plug in for IES and this appears to be much better
> >>> than relying on the gbxml output of revit.
> >>>
> >>> DesignBuilder is the tool that I use most now in both SBEM (UK
> >>> regulations format) and EnergyPlus for dynamic modelling. It
> >>> takes a lot of the best features of both IES and TAS and then
> >>> adds some other nice touches in terms of data application to
> >>> speed up the process of setting up your models. The only
> >>> sticking point with it is that EnergyPlus is painfully slow.
> >>> The main thing I’d like is for that to be changed and
> >>> improved. Carrying out simulations with all the lighting
> >>> controls and calculated natural ventilation turned on for
> >>> buildings with over 100 zones is nigh on impossible as I don’t
> >>> fancy leaving it running for a week or two. I have to carry
> >>> out major sub-division of models or calculate individual zones
> >>> then schedule up the vent based on those results or just go
> >>> with scheduled vent. Thankfully the reporting methodology from
> >>> DesignBuilder is pretty good, though I have to admit I quite
> >>> like some of the report wizard output by equest.
> >>>
> >>> The main advantage of the commercial tools as opposed to the
> >>> free tools such as DOE and equest, is that they use an
> >>> interactive 3d model to input the building and that you can
> >>> interrogate much more easily for post-processing. This means
> >>> you gain an understanding of the building form much more
> >>> easily and many link with other tools for further analysis. I
> >>> like some of what equest has to offer, but I much prefer the
> >>> interactive model building tools that IES, TAS and
> >>> DeisgnBuilder offer. They just make it...easier...and
> >>> generally quicker and more efficient when you consider the
> >>> other studies that you can do (e.g daylighting, CFD, etc).
> >>>
> >>> In terms of asking for changes – having worked for IES (and
> >>> with many other developers), the stock answer even to their
> >>> own team was...yes it’s on the list. My guess is that will
> >>> still be the same.
> >>>
> >>> Regards
> >>>
> >>> Paul
> >>>
> >>> Dr Paul Carey
> >>>
> >>> Director
> >>>
> >>> Low Carbon Energy Assessor
> >>>
> >>> Zero Energy Design Ltd
> >>>
> >>> 10A Portland Place
> >>>
> >>> 2-22 Mottram Road
> >>>
> >>> Stalybridge
> >>>
> >>> SK15 3AD
> >>>
> >>> T: 0161 3386200
> >>>
> >>> F: 0161 3031281
> >>>
> >>> M: 0789 4098012
> >>>
> >>> E: paul at zed-uk.com <mailto:paul at zed-uk.com>
> >>>
> >>> W: www.zed-uk.com <http://www.zed-uk.com/>
> >>>
> >>> Certificate No: GB16647
> >>>
> >>> Certificate No: GB16646
> >>>
> >>> Please carefully consider the environment
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> >>>
> >>> *From:* bldg-sim-bounces at lists.onebuilding.org
> >>> <mailto:bldg-sim-bounces at lists.onebuilding.org>
> >>> [mailto:bldg-sim-bounces at lists.onebuilding.org
> >>> <mailto:bldg-sim-bounces at lists.onebuilding.org>] *On Behalf Of
> >>> *Karen Walkerman
> >>> *Sent:* 25 February 2009 23:06
> >>> *To:* Varkie C Thomas
> >>> *Cc:* Varkie Thomas; bldg-sim at lists.onebuilding.org
> >>> <mailto:bldg-sim at lists.onebuilding.org>
> >>> *Subject:* Re: [Bldg-sim] IES-VE Energy
> >>>
> >>> 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 <mailto:thomasv at iit.edu>
> >>> <mailto:thomasv at iit.edu <mailto: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
> >>>
> >>>
> >>> ------------------------------------------------------------------------
>
> >>>
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