[Bldg-sim] Modelling for retrofit ECM's (OT)
Chris Yates
chris.malcolm.yates at gmail.com
Wed Feb 9 08:18:37 PST 2011
Thanks a lot guys and once again sorry to Jeff for taking it OT.
It seems that air walls mean different things in different simulation
environments. It's been really helpful understanding what modellers from
the DOE2 pedigree use. My principle experience with these "Air walls"
has been within the micro-tradition of IES. Amongst IES users the trend
seems to be to model air walls as holes, transparent to solar beam,
acting as a "diffusing layer" to longwave radiation (but with Emissivity
= 1). IES can also model bulk air flow between one zone and the next
using macroflo.
This method has its uses, but can also be abused somewhat by users
trying to do "CFD"!
You've been very helpful, thanks
Chris
On 09/02/2011 15:12, Nick Caton wrote:
>
> Suwon is quite right -- the limitations of system quantities per zone
> is a major reason we need air partitions to model actual designs.
> There are a variety of other situations in which a massless partition
> becomes useful...
>
> In programs like eQuest/DOE2 which are not modeling hourly CFD for air
> movement, air surfaces may also be used to approximate/enforce thermal
> layering in large volumes such as a gym or an atrium, separating the
> "conditioned" volume at the occupied levels from the other layers.
>
> The ability to model air walls in place of a construction with mass
> also permits the option to explore limited layout changes such as
> knocking down a wall to "thermally connect" two spaces.
>
> In summary, "artificial boundaries" can be a pretty useful tool when
> one intends to model a variety of things with a higher degree of
> accuracy.
>
> It appears to me Jeff is making a broader point in the context of the
> papers/experiences he is posting, using air walls / approximate zoning
> as a specific case-in-point: Approximating rough partitions/zoning in
> an existing building with air walls, even when the exact layout /
> thermal massing of the actual partitions is known, can be sufficient,
> _even necessary_, when the intent is to "fit" a model to "real" data.
> He's not suggesting thermal construction lag isn't real or important
> to model in all cases, but rather that the assumption such behavior is
> unaffected by un-modeled/un-measured factors can itself be misleading.
>
> ~Nick
>
> cid:489575314 at 22072009-0ABB**
>
> **
>
> *NICK CATON, E.I.T.***
>
> PROJECT ENGINEER
>
> Smith & Boucher Engineers
>
> 25501 west valley parkway
>
> olathe ks 66061
>
> direct 913 344.0036
>
> fax 913 345.0617
>
> www.smithboucher.com__
>
> *From:*songsuwon [mailto:ssw1007 at hotmail.com]
> *Sent:* Wednesday, February 09, 2011 4:01 AM
> *To:* chris.malcolm.yates at gmail.com; Nick Caton
> *Cc:* bldg-sim at lists.onebuilding.org
> *Subject:* RE: [Bldg-sim] Modelling for retrofit ECM's
>
> Hi Chris,
>
> In most building energy simulation programs including DOE-2, It is
> impossible to define two different HVAC systems in one thermal
> zone. Therefore, it is sometimes useful to seperate one actural zone
> into two thermal zones(e.g. interior zone and perimeter zone) using an
> articificial boundary like 'air wall' when an actual one zone in
> existinfg building has two different systems, for example, VAV system
> is for a interior zone, and fan coil unit is for a perimeter zone.
>
> Suwon Song
>
> ------------------------------------------------------------------------
>
> Date: Wed, 9 Feb 2011 08:23:51 +0000
> From: chris.malcolm.yates at gmail.com
> To: ncaton at smithboucher.com
> CC: bldg-sim at lists.onebuilding.org
> Subject: Re: [Bldg-sim] Modelling for retrofit ECM's
>
> Sorry Nick, my bad regarding the tangent. What you've described in
> eQuest seems synonymous with the NoMass material in Energyplus.
>
> Perhaps I can bring it a little bit back on topic. Jeff mentions the
> use of Air walls to model existing buildings. However, if you know
> where all the partitions are in an /existing/ building don't they
> introduce artificial boundaries?
>
> Chris
>
> On 08/02/2011 19:10, Nick Caton wrote:
>
> This thread appears to have tangented into 3+ different directions...
> if you have a new inquiry please start a new email chain =)!
>
> Fransisco -- you should refine your questions by specifying which
> program you intend to use, or if your inquiry is of the "is there a
> program that can do this?" variety. Air walls _in eQuest_/_DOE2_
> behave as Suwon is describing. They are a type of interior partition
> and will not model heat transfer to the exterior, regardless of their
> geometrical location.
>
> Chris -- I use eQuest/DOE2 primarily. Please refer to recent
> discussion on [eQuest-users] where I attempted to sum up air wall
> behavior in both layman's and complex terms (discussion attached).
>
> To my understanding DOE2/eQuest models do not model heat transfer
> explicitly by either convection or radiation -- all heat movement
> within the model is calculated as a series of direct (conductive)
> transfers between zone surfaces (interior and exterior) on an hourly
> basis. Air walls are unique type of surface in that they have zero
> mass but a relatively low conductivity (by default, approximately the
> same as a single layer of 3/8" Gypsum), however this value can be
> modified as may be desired.
>
> To Rohini -- My existing model calibration experience is probably
> limited relative to others contributing -- but I can share the general
> observation/advice that your models can only ever be as accurate as
> your gathered data, or lack thereof. An important corollary I want to
> emphasize is that models ultimately serve a purpose, and that it's
> important at the beginning of any project to identify that endgame.
> Sometimes it's getting LEED points, sometimes it's advising new or
> retrofit design for existing envelopes, HVAC, and/or lighting,
> sometimes it's because there's academics who simply want a model they
> can pick up after you to tweak to perfection as time goes on...
>
> Defining where the model is headed in terms of intent will permit you
> to define a degree/deadband of acceptable accuracy. Without doing so,
> you may lose sanity/sleep to the beast before realizing you don't have
> a finish line defined.
>
> ~Nick
>
> cid:489575314 at 22072009-0ABB
>
> **
>
> *NICK CATON, E.I.T.*
>
> PROJECT ENGINEER
>
> Smith & Boucher Engineers
>
> 25501 west valley parkway
>
> olathe ks 66061
>
> direct 913 344.0036
>
> fax 913 345.0617
>
> www.smithboucher.com <http://www.smithboucher.com/>__
>
> *From:*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
> *Francisco Massucci
> *Sent:* Tuesday, February 08, 2011 10:14 AM
> *To:* bldg-sim at lists.onebuilding.org
> <mailto:bldg-sim at lists.onebuilding.org>
> *Subject:* Re: [Bldg-sim] Modelling for retrofit ECM's
>
> Hi,
>
> Is it possible to simulate an open door or a open window in a face
> with outdoors boundary conditions? (only calculating heat loss or
> gains to the enviroment). Example: If I apply a "infrared transparent'
> in a exterior window, does it works as a open window, for energy
> balance calculation?
>
> Sorry about my english.
>
> Thanks,
>
> Francisco Massucci
>
> On Tue, Feb 8, 2011 at 12:14 PM, songsuwon <ssw1007 at hotmail.com
> <mailto:ssw1007 at hotmail.com>> wrote:
>
> Hi all,
>
>
> In DOE-2 program, "air wall" is a type of interior walls without
> thermal mass effect, only for thermal resistance(0.9
> hr-ft2-F/btu) between zones. I think other similar simulation
> programs have also the same function.
>
> Suwon Song
>
> ------------------------------------------------------------------------
>
> Date: Tue, 8 Feb 2011 09:40:22 -0200
> From: massucci at gmail.com <mailto:massucci at gmail.com>
> To: bldg-sim at lists.onebuilding.org
> <mailto:bldg-sim at lists.onebuilding.org>
>
>
> Subject: Re: [Bldg-sim] Modelling for retrofit ECM's
>
> Hi all,
>
> I would like to add a question to the list:
>
> - Air wall works the same when apllied in a between zones face or in
> an outdoor face?
>
> thanks
>
> Francisco Massucci
>
> On Tue, Feb 8, 2011 at 6:24 AM, Chris Yates
> <chris.malcolm.yates at gmail.com <mailto:chris.malcolm.yates at gmail.com>>
> wrote:
>
> Dear Jeff,
>
> You mention the use of "Real walls or *_air walls_*" between zones in
> your post. I feel this raises a question on this list that I've
> already enquired on this list. I apologise for raising the issue once
> more, however I did not feel that the discussion resulted in a clear
> conclusion of how various simulation programs may treat "Air walls" or
> "virtual partitions".
>
>
> I hope you don't mind me asking:
>
> * what programs do you use mainly?
> * under normal modelling practice, how would these programs treat
> "air walls" with respect to:
>
> o Conduction
> o Long-wave radiation
> o Short-wave radiation
> o Air flow
>
> Many thanks
>
> Chris
>
> On 05/02/2011 22:04, Jeff Haberl wrote:
>
> ALSO:
>
>
> Here are a few papers that shed light on the ELF/OLF proxy method and
> other findings, somewhat dated but useful:
>
> Haberl, J., Komor, P. 1990. "Improving Commercial Building Energy
> Audits: How Daily and Hourly Consumption Data Can Help," /ASHRAE
> Journal, /Vol. 32, No. 9, pp. 26 - 36 (September).
>
> Haberl, J., Komor, P. 1990. "Improving Commercial Building Energy
> Audits: How Annual and Monthly Consumption Data Can Help," /ASHRAE
> Journal,/ Vol. 32, No. 8, pp. 26 - 33 (August).
>
> Haberl, J., Komor, P. 1989. "Status Report on Methods for Using
> Hourly, Daily and Monthly Data to Provide Useful Information on
> Building Energy Use," submitted to the New Jersey Energy Conservation
> Lab, Center for Energy and Environmental Studies at Princeton
> University, Princeton, New Jersey (May).
>
> Haberl, J., Komor, P. 1989. "Investigating An Analytical Basis for
> Improving Commercial Building Energy Audits: Early Results from a New
> Jersey Mall," /Thermal Performance of the Exterior Envelopes of
> Buildings IV,/ ASHRAE, Atlanta, Georgia, pp. 302 - 331 (December).
>
> Haberl, J., Komor, P., Haberl, J. 1989. "Investigating An Analytical
> Basis for Improving Commercial Building Energy Audits: Results from a
> New Jersey Mall," Center for Energy and Environmental Studies Report
> No. 264 (June).
>
> ------------------------------------------------------------------------
>
> *From:*bldg-sim-bounces at lists.onebuilding.org
> <mailto:bldg-sim-bounces at lists.onebuilding.org>
> [bldg-sim-bounces at lists.onebuilding.org
> <mailto:bldg-sim-bounces at lists.onebuilding.org>] on behalf of Jeff
> Haberl [jhaberl at tamu.edu <mailto:jhaberl at tamu.edu>]
> *Sent:* Saturday, February 05, 2011 3:44 PM
> *To:* Carol Gardner; R B
> *Cc:* bldg-sim at lists.onebuilding.org
> <mailto:bldg-sim at lists.onebuilding.org>
> *Subject:* Re: [Bldg-sim] Modelling for retrofit ECM's
>
> Rohini,
>
> Zoning a building is still an art form. There are very few papers that
> have looked into this with any rigor.
>
> In one thesis we did on the Zachry building, which was the basis for
> the Predictor Shootout I and II, we looked at 1, 2, 5 and actual
> zoning on the building. What we saw was that, in general, the centroid
> of the "cloud" of data points remained about the same. However, the
> scatter in the cloud became more pronounced at we added more zones.
>
> So, if all the zones in the floor are being operated the same, I'd use
> 1, 2 or 5 zones per floor, depending on the functions of what's going
> on in each zone. Real walls or air walls between the zones usually get
> the job done.
>
> The quickest way to get the light and receptacle loads on a real
> building is using "blink" tests, which can be done on a Saturday, with
> walkie talkies, and a data logger on the whole-building electric feed,
> possibly some sub feeds. I first heard of this test from Todd Taylor
> at PNNL. We've used it to help resolved motor loads, lighting loads,
> receptacles, etc. Seems to work pretty well.
>
> There are also several ways to get the plug loads, including: by
> proxy, by weather-day-type profiles, by daily readings, and a method
> that uses an energy balance. The proxy methods can use square proxies
> for for the occupancy based on OLF/ELF ratios, the weather-day-type
> method was something that I heard about from Don Hadley at PNNL, later
> adopted by Bou Saada on the Forrestal building and daycare center. The
> daily readings are just that, read the main meter by eye, daily,
> especially during weather independent times. The energy balance method
> is documented in papers by Claridge et al. at the ESL.
>
> There is also some encouraging work being done by Abushakra and Reddy
> on ASHRAE RP 1404, now in progress and scheduled for completion later
> this year. This is based on previous work by Abushakra for his Ph.D.
> thesis.
>
> Hope this helps.
>
> Jeff
>
>
> PS: here are some helpful papers:
>
> Song, S., Haberl, J. 2008. "A Procedure for the Performance Evaluation
> of a New Commercial Building: Part I -- Calibrated As-built
> Simulation", /ASHRAE Transactions-Research, /Vol. 114, Pt. 2, pp.
> 375-388 (June ).
>
> Song, S., Haberl, J. 2008. "A Procedure for the Performance Evaluation
> of a New Commercial Building: Part II -- Overall Methodology and
> Comparison of Results", /ASHRAE Transactions-Research, /Vol. 114, Pt.
> 2, pp. 389 -- 403 (June).
>
> Claridge, D., Abushakra, B., Haberl, J. 2003. "Electricity Diversity
> Profiles for Energy Simulation of Office Buildings (1093-RP)," /ASHRAE
> Transactions-Research,/ Vol. 110, Pt. 1 (February), pp. 365-377.
>
> Haberl, J., Bou-Saada, T. 1998. "Procedures for Calibrating Hourly
> Simulation Models to Measured Building Energy and Environmental Data,"
> /ASME Journal of Solar Energy Engineering/, Vol. 120, pp. 193 - 204
> (August).
>
> Haberl, J., Bronson, D., O'Neal, D. 1995. "An Evaluation of the Impact
> of Using Measured Weather Data Versus TMY Weather Data in a DOE-2
> Simulation of an Existing Building in Central Texas," /ASHRAE
> Transactions-Research, /Vol. 101, Pt.. 2, pp. 558 - 576 (June).
>
> Haberl, J., Bronson, D., Hinchey, S., O'Neal, D. 1993. "Graphical
> Tools to help Calibrate the DOE-2 Simulation Program to Non-weather
> Dependent Measured Loads," /ASHRAE Journal/, Vol. 35, No. 1, pp. 27 -
> 32 (January).
>
> Haberl, J., MacDonald, M., Eden, A. 1988. "An Overview of 3-D
> Graphical Analysis Using DOE-2 Hourly Simulation Data," /ASHRAE
> Transactions-Research, /Vol. 94, Pt. 1, pp. 212 - 227 (January).
>
> Kim, K., Haberl, J. 2010. "Development of a Calibration Methodology
> for Code-Complaint Simulation With Results From Using a Case-Study
> House in a Hot and Humid Climate", /Proceedings of the 17th Symposium
> on Improving Building Systems in Hot and Humid Climates,/ Texas A&M
> University, Austin, Texas, accepted for publication (May).
>
> Bronson, D., Hinchey, S., Haberl, J., O'Neal, D. 1992. "A Procedure
> for Calibrating the DOE-2 Simulation Program to Non-Weather Dependent
> Loads," /ASHRAE Transactions-Research, /Vol. 98, Pt. 1, pp. 636 - 652
> (January).
>
>
> 8=! 8=) :=) 8=) ;=) 8=) 8=( 8=) 8=() 8=) 8=| 8=) :=') 8=)8=?
>
> Jeff S. Haberl, Ph.D.,P.E., FASHRAE..............jhaberl at tamu.edu
> <mailto:FASHRAE..............jhaberl at tamu.edu>
>
> Professor............................................................Office
> Ph: 979-845-6507
>
> Department of Architecture.............................Lab Ph:979-845-6065
>
> Energy Systems Laboratory.............................FAX: 979-862-2457
>
> Texas A&M University.....................................77843-3581
>
> College Station, Texas, USA,
> 77843..................URL:www.esl.tamu.edu <http://www.esl.tamu.edu/>
>
> 8=/ 8=) :=) 8=) ;=) 8=) 8=() 8=) :=) 8=) 8=! 8=) 8=? 8=)8=0
>
> ------------------------------------------------------------------------
>
> *From:*bldg-sim-bounces at lists.onebuilding.org
> <mailto:bldg-sim-bounces at lists.onebuilding.org>
> [bldg-sim-bounces at lists.onebuilding.org
> <mailto:bldg-sim-bounces at lists.onebuilding.org>] on behalf of Carol
> Gardner [cmg750 at gmail.com <mailto:cmg750 at gmail.com>]
> *Sent:* Saturday, February 05, 2011 12:59 PM
> *To:* R B
> *Cc:* bldg-sim at lists.onebuilding.org
> <mailto:bldg-sim at lists.onebuilding.org>
> *Subject:* Re: [Bldg-sim] Modelling for retrofit ECM's
>
> Hi Rohini,
>
> When you are bill matching there are not magical ways of doing things.
> You pretty much have to put what's in the building in your model.
> Those things you can control. The tricky part is to figure out how the
> building is really being operated and to get the most accurate weather
> data you can for your site.
>
> Cheers,
>
> Carol
>
> On Fri, Feb 4, 2011 at 8:34 AM, R B <slv3sat at gmail.com
> <mailto:slv3sat at gmail.com>> wrote:
>
>
> Hi All,
>
> While modelling existing building (with calibration to utility bill),
> do you model every VAV zone or lump similar ones together? What could
> be possible disadvantages of lumping down the road? Any ECM's that
> will be affected by this simplification?
>
> Is there a magical way to figure the W/sqft for lighting and plug
> loads without having to count everything on site?
>
> Thanks for any insights.
>
> -Rohini
>
>
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>
>
> --
> Carol Gardner PE
>
>
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> --
>
> Chris Yates C Eng MCIBSE
> /Building Physics Consultant/
> Tel: +447960731576
> Email: chris.malcolm.yates at gmail.com
> <mailto:chris.malcolm.yates at gmail.com>
> Skype: christopher.m.yates
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> --
>
> Chris Yates C Eng MCIBSE
> /Building Physics Consultant/
> Tel: +447960731576
> Email: chris.malcolm.yates at gmail.com
> <mailto:chris.malcolm.yates at gmail.com>
> Skype: christopher.m.yates
>
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--
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/Building Physics Consultant/
Tel:+447960731576
Email: chris.malcolm.yates at gmail.com
Skype: christopher.m.yates
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