[Equest-users] newbie question on simple modeling

[Darrell Cherry]

Carol & Alex,

 

This is VERY helpful.  I will make an initial run at it and post if more questions come up.  Thanks so much for your input!

 

 

Cordially,

Darrell Cherry | Sr Projects Manager

JE Berkowitz, LP | Architectural Glass Since 1920

One Gateway Boulevard | Pedricktown, NJ  08067

T 800.257.7827 x207| F 856.299.4344 | C 856.229.1598

dcherry at jeberkowitz.com | www.jeberkowitz.com <http://www.jeberkowitz.com> 

 

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From: equest-users-bounces at lists.onebuilding.org [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Carol Gardner
Sent: Wednesday, October 27, 2010 7:03 PM
To: Alex Krickx
Cc: eQUEST Users List
Subject: Re: [Equest-users] newbie question on simple modeling

 

Yes, I would do take the xx% reduction and apply it to the existing usage. My thought process would be that since I am effectively only reducing the loads to the space - heating and cooling - and not making any other changes that I am just dealing with a delta in the usage. So if I figured out what that was for a fairly similar building and then used the reduction percent I should be good. I good get a little more fancy and figure the xx% reduction in cooling and the yy% reduction in heating, if I had actual usage info about the two, that is.

Carol

On Wed, Oct 27, 2010 at 3:38 PM, Alex Krickx <akrickx at seriousmaterials.com> wrote:

Hi Carol,

 

So I have a question about what you've said:

 

Let's take your example of investigating a window change, and let's make it for an existing building. Let's put in the right building type (say office) and the right location, building shape/size/orientation, update the occupancy schedules, and put in the right HVAC system type  - and then leave the rest as defaults. If you were to model the existing windows vs. improved windows, I would guess that the natural gas consumption in this model would be 50% or even less than the actual building's consumption. The existing system will have inefficiencies that eQUEST will not assume as a default.

 

In any case, your result can be described in two ways- an XX% reduction from existing windows, and YY-MBTU reduction. Which of those is more representative of what the savings will be.

 

If the model's consumption is less than the actual buildings, and you present savings in the YY-MBTU format, then you are probably underpredicting how much energy could be saved. In that case, would you take the XX% savings you've just calculated and apply that to the existing building's consumption?

 

I'm not talking about sizing systems here, but more trying to examine the impacts of investigating energy-savings options.

 

Just interested in your 2¢.

 

Cheers,

Alex 

 

From: equest-users-bounces at lists.onebuilding.org [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Carol Gardner
Sent: Wednesday, October 27, 2010 2:05 PM
To: Nick Caton
Cc: equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] newbie question on simple modeling

 

I agree with every thing Nick said. I'd add that if you want to calibrate your model to actual utility bills a very important thing to understand is how the building is used, i.e., when are people arriving? Leaving? How and when are lights, equipment, etc. turned on? How is the HVAC system operated? All of this information goes into schedules which modify the number of people (total bldg population), w/sf of light and HVAC systems. These schedules are the "art" of calibration and the most powerful tool to use. The other thing that will impact your calibration will be the weather file, which you unfortunately can't control unless you want to create your own file. Overkill.

This being said, if you are just examining a condition like a window change out you don't really need to calibrate, I don't think. As Nick said in his first response you're just looking at a before and after condition - existing window vs new window so I don't think having a precise model of your building will matter so much.

Maybe others will disagree. If so bring it on!

On Wed, Oct 27, 2010 at 10:19 AM, Nick Caton <ncaton at smithboucher.com> wrote:

Sounds like you've run head-on into a conundrum we all continually face as energy modelers - how accurate is accurate enough?

 

The savings generated by any glazing retrofit ultimately boil down to altering the envelope loads the building has to deal with (solar/conductive)*.  Your real goal is to have those loads' magnitudes in the right ballpark before doing a comparison.

 

You should definitely try to use the real-world utility rates, location, geometries and envelope constructions of the existing building for this study when making your baseline in the wizards.  

 

To what degree you should calibrate your baseline results depends on your time available, ability (what you can do in that time) and what degree of accuracy is desired in the results - it's ultimately your call.  If you're a total beginner without time to burn, I'd suggest at a bare minimum to collect and try to roughly match some historical utility bills on an annual basis.  If the actual building spends $200,000 a year on gas/electricity and your generic baseline spits out half that, you will definitely want to improve your model before generating/sharing any results.   This would provide a (rough) measure of whether your model is accurately ball parking the envelope loads correctly.

 

You're correct regarding the overall procedure: make the baseline first, check and calibrate its behavior to the degree you feel appropriate, then change the glazing for comparative results.  

 

You might do well to read up on parametric runs first to save yourself time and streamline the process - then you can simultaneously explore multiple alternatives within one file.  Also don't miss the significance of the "use floor multipliers" checkbox in the wizards whenever doing high-rise building models.

 

~Nick

 

*... unless there's daylighting controls involved too, in which case you should collect as much info regarding those lightings systems/controls as you can to match in your baseline as well!

 

 

 

NICK CATON, E.I.T.

PROJECT ENGINEER

25501 west valley parkway

olathe ks 66061

direct 913 344.0036

fax 913 345.0617

Check out our new web-site @ www.smithboucher.com <http://www.smithboucher.com>  

 

From: Darrell Cherry [mailto:DCherry at jeberkowitz.com] 
Sent: Wednesday, October 27, 2010 10:43 AM
To: Nick Caton
Subject: RE: [Equest-users] newbie question on simple modeling

 

Nick, thank you.  What specific parameters would you recommend I obtain from building owner in order to provide more realistic analysis?  Rates?  HVAC plant and zoning info? Time-of-use rates?  Etc.?

 

I assume what I need to do is create a baseline of the current building and its current energy costs/rates and after that is done I will simply change the one component I plan to affect; i.e. glazing, and then run the comparison.

 

 

Cordially, 
Darrell Cherry | Projects Manager 
JE Berkowitz, LP | Architectural Glass Since 1920 
One Gateway Boulevard | Pedricktown, NJ  08067 
T 800.257.7827 x207| F 856.299.4344 | C 856.229.1598 
dcherry at jeberkowitz.com <mailto:dcherry at jeberkowitz.com>  | www.jeberkowitz.com <http://www.jeberkowitz.com>  
  
* * * * * * * * * * * CONFIDENTIALITY NOTICE * * * * * * * * * * * *
This email including any files transmitted with it, are confidential and 
intended solely for the use of the individual or entity to whom they are 
addressed. If you have received this email in error please delete it, in its 
entirety, from your system. 
  

________________________________

From: Nick Caton [mailto:ncaton at smithboucher.com] 
Sent: Wednesday, October 27, 2010 11:37 AM
To: Darrell Cherry; equest-users at lists.onebuilding.org
Subject: RE: [Equest-users] newbie question on simple modeling

 

"Is this just too simplistic for eQuest?"

 

...There's  a question we don't see often here =)!

 

eQuest can be used to quickly build a generic 19-story office building from the wizards.  

 

eQuest can easily be used to compare the effects of two glazing materials.

 

What eQuest cannot do (nor any other software), is calibrate to accurately model "current annual energy costs" and "improved" costs with only one bit of information - glass type.  

 

As long as you intend to estimate "relative annual energy savings," you should be fine using eQuest to make as simplified a comparison as you might desire.  

 

Just keep in mind: the less effort spent attempting to match reality with your baseline model, the more of an estimate the whole exercise really is.

 

~Nick



 

NICK CATON, E.I.T.

PROJECT ENGINEER

25501 west valley parkway

olathe ks 66061

direct 913 344.0036

fax 913 345.0617

Check out our new web-site @ www.smithboucher.com <http://www.smithboucher.com>  

 

From: equest-users-bounces at lists.onebuilding.org [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Darrell Cherry
Sent: Wednesday, October 27, 2010 9:54 AM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] newbie question on simple modeling

 

I need to utilize eQuest for basically one simple purpose; i.e. I am looking to change ONLY the makeup of the windows in a 19-story office building from monolithic glazing to a triple-glazed system.  The frame WILL NOT change.

 

What I need to model is the current annual energy costs vs ne costs with improved fenestration system.

 

Is this just too simplistic for eQuest?


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-- 
Carol Gardner PE




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Carol Gardner PE

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