[Equest-users] newbie question on simple modeling

Wed Oct 27 16:03:16 PDT 2010

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!
>
>
>
> [image: cid:489575314 at 22072009-0ABB]
>
> * *
>
> *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* *
>
>
>
> *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 | www.jeberkowitz.com
>
> ** * * * * *** *** * * * *** **CONFIDENTIALITY NOTICE * * * * * * *** ***
> * * * **
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>   ------------------------------
>
> *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
>
> [image: cid:489575314 at 22072009-0ABB]
>
> * *
>
> *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* *
>
>
>
> *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
>

-- 
Carol Gardner PE
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