[Equest-users] DD Wizard: Discrepancies between Proposed andBaseline

Tue Nov 2 14:22:25 PDT 2010

When you want to learn to swim with the sharks, you'll learn how to edit in
BDL.

Carol

On Tue, Nov 2, 2010 at 2:16 PM, Nick Caton <ncaton at smithboucher.com> wrote:

>  Hi Kristy!
>
>
>
> A majority of the variables affecting fan power (scheduling, kW/CFM…)
> aren’t explicitly specifiable until you are in detailed mode.
>
>
>
> That said, a CV heatpump system may well consume less fan power than a VAV
> system as you (1) don’t have as many fans in quantity and (2) your CV fan
> may be running intermittently whereas a VAV system has a main fan running
> constantly / on a schedule.
>
>
>
> Note that by limiting yourself to the wizards you are only able to specify
> inexact “standard/high/premium” efficiencies, whereas if you moved into
> detailed you could specify these to your liking to get a more accurate
> reading on total fan energy consumption.
>
>
>
> If you are unhappy that the cooling consumptions reported aren’t equal,
> adjusting the corresponding cooling efficiencies is probably about all you
> can do to affect that if you’re stuck in the wizards.
>
>
>
> Fundamentally, all things being equal however, a VAV system with reheat (?)
> is probably going to consume more energy cooling supply air, as you’re now
> providing cooling to supply air that needs to be reheated in some zones
> during certain seasons.  What you gain in occupant comfort you might lose in
> cooling consumption!
>
>
>
> Kristy, the following is less for you and more for the group at large, as I
> understand you’re a veteran here ;):
>
>
>
> Whenever your “wizards only” model is not behaving properly and time
> permits, I’d encourage you to temporarily pop into detailed mode to explore
> everything the wizards are really specifying as a means of learning the
> why’s and wherefore’s of your modeled behavior.  As newer modelers learn
> eQuest/DOE2, the wizards can be viewed as something like a set of training
> wheels that eventually you need to remove before you can really compete in a
> race.  For all they do to simplify and streamline creating a model, the
> wizards are frankly limiting.  Until you can swim in the deep end of the
> pool, you can’t dive to the deepest depths.
>
>
>
> Experienced modelers will intentionally decide to use “wizard-bound” models
> to explore things in a time-efficient manner, but that decision hinges on
> knowing and accepting in what fashion the variables are limited and
> determining those limitations are acceptable for the study at-hand.  Do not
> avoid detailed mode based solely on any level of discomfort you have with
> the level of control you are granted – dive in!  In the worst case, you can
> always pop back to the wizards.
>
>
>
> ~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 *Walson, Kristy
> *Sent:* Tuesday, November 02, 2010 2:51 PM
> *To:* eQUEST Users List
> *Subject:* [Equest-users] DD Wizard: Discrepancies between Proposed
> andBaseline
>
>
>
> Hello Equest friends,
>
>
>
> I am working in the DD Wizard (and trying to not move into Detailed Mode),
> building the Proposed and Baseline models for a project that is in the
> middle of design.  I took the Proposed model file and did a "Save As" to
> create the Baseline model, so I know that the two models are starting out
> the same.  My Proposed HVAC system is a Packaged VAV with Electric Heat and
> my Baseline system is a Packaged Heat Pump Constant Volume.  When I only
> change the system type in the Baseline model from the Proposed Pkgd VAV to
> the Constant Vol. HP, my annual energy consumption for cooling reduces in
> the Baseline model (I would expect no change), the heating consumption
> reduces (this is to be expected), *and the fan power goes down in the
> baseline*.  I can't figure out, when I change from a VAV to a Constant
> Volume system why the fan power would ever go down.  I was hoping to make up
> for the HP's better heating efficiency through reduced fan power.
>
>
>
> This just doesn't make sense to me.  Remember, I'm still in the DD Wizard
> and only have limited access to changes.  Can anyone explain this to me and
> offer advice on how to achieve more predictable results?  Thanks in advance
> for the help.
>
>
>
> *Kristy M. Walson, PE, LEED AP*
>
> *Mechanical Engineer / Sustainable Design*
>
>
>
> *TLC Engineering for Architecture
> **Your 2030 Challenge Partner*
>
>
>
> 255 South Orange Avenue, Suite 1600
>
> Orlando, FL 32801-3463
>
>
>
> phone:
>
> 407-841-9050
>
> fax:
>
> 407-425-7367
>
> direct:
>
> 407-487-1118
>
> website:
>
> www.tlc-engineers.com
>
>
>
> [image: http://www.tlc-engineers.com/images/TLC_Sig_Loc_Block.gif]<http://www.tlc-engineers.com/>
>
> Please consider the environment before printing this email.
>
>
>
> _______________________________________________
> Equest-users mailing list
> http://lists.onebuilding.org/listinfo.cgi/equest-users-onebuilding.org
> To unsubscribe from this mailing list send  a blank message to
> EQUEST-USERS-UNSUBSCRIBE at ONEBUILDING.ORG
>
>

-- 
Carol Gardner PE
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.onebuilding.org/pipermail/equest-users-onebuilding.org/attachments/20101102/399e8b20/attachment.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: image/jpeg
Size: 1459 bytes
Desc: not available
URL: <http://lists.onebuilding.org/pipermail/equest-users-onebuilding.org/attachments/20101102/399e8b20/attachment.jpeg>