[Bldg-sim] Modelling for retrofit ECM's

songsuwon ssw1007 at hotmail.com
Wed Feb 9 02:01:04 PST 2011


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
 

 
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: 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
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> 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
To: 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> 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:


 Conduction
Long-wave radiation
Short-wave radiation
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 [bldg-sim-bounces at lists.onebuilding.org] on behalf of Jeff Haberl [jhaberl at tamu.edu]
Sent: Saturday, February 05, 2011 3:44 PM
To: Carol Gardner; R B
Cc: 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

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

8=/  8=)  :=)  8=)  ;=)  8=)  8=()  8=)  :=)  8=)  8=!  8=)  8=? 8=)8=0





From: bldg-sim-bounces at lists.onebuilding.org [bldg-sim-bounces at lists.onebuilding.org] on behalf of Carol Gardner [cmg750 at gmail.com]
Sent: Saturday, February 05, 2011 12:59 PM
To: R B
Cc: 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> 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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