[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
> >>>
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> >>>
> >>>         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/>
> >>>
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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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