[Equest-users] More about fans

[Carol Gardner]

I owe you all an apology. I sent an email to Vikram using the reply vs
reply-all button telling him that I thought his problem might be in
specifying the curve as linear. He changed it to quadratic and got much more
reasonable results.
Carol

On Fri, Mar 5, 2010 at 3:34 PM, Bill <bkoran at qwest.net> wrote:

>  Steven, Vikram, et. al.,
>
> Reid communictated with me in developing that presentation, since I
> authored the spreadsheet tool.  As the author of the tool, I will vouch for
> the analytical approach, and the tool was peer reviewed since it was funded
> by the California Commissioning Collaborative.
>
> As for tool useability, well, it is pretty useable but not where I would
> like it to be.  The tool (and others) is available at:
> http://www.cacx.org/resources/rcxtools/spreadsheet_tools.html
> It was developed in Excel 2003; I am uncertain whether there are any issues
> with other versions.
>
> Yes, I believe the default DOE-2/eQuest VAV curves are quite optimistic.
> Even the tool that comes out of my spreadsheet tool is likely somewhat
> optimistic, even though it attempts to include fan, VFD, and motor
> efficiencies at the various operating points.  Pressure drops relative to
> flow could be slightly better modeled for the portion of the system with
> filters and coils, and that would further increase off-design power.
>
> How well a particular curve fits a particular system is most significantly
> a function of
> (1) whether and how the static pressure setpoint (to which the VFD controls
> the fan speed) is reset.
> (2) if the static pressure setpoint is not reset, where the sensor is in
> the duct system, and how high the setpoint is relative to the fan pressure
> rise.
>
> This figure is related to what Reid showed in his presentation, and relates
> some of these issues.
>
>  --Bill
>
>
>
>
> William E. Koran, P.E.
> Senior Engineer
> Q u E S T
> Quantum Energy Services and Technologies
> 3945 Parker Road
> West Linn, OR  97068
> Voice: 503-557-7828
> Fax: 510-540-7268
> Web: ***www.quest-world.com*
>
>  ------------------------------
> *From:* equest-users-bounces at lists.onebuilding.org [mailto:
> equest-users-bounces at lists.onebuilding.org] *On Behalf Of *Steven Savich
> *Sent:* Friday, March 05, 2010 3:03 PM
> *To:* 'Vikram Sami'; 'eQUEST Users List'
> *Subject:* Re: [Equest-users] More about fans
>
>  Vikram,
>
>
>
> Reid Hart of PECI did a presentation on this issue for the building
> simulation user's group a few months ago, and discussed a spreadsheet tool
> to construct accurate DOE2 performance curves for variable flow air and
> water systems.  I believe the powerpoint presentation is still archived on
> the BSUG yahoo site, and the spreadsheet is downloadable from PECI's
> website.  I haven't tried using this tool yet, so I cannot vouch for its
> accuracy or useability.
>
>
>
> Steven
>
>
>
> Steven Savich, LEED AP
>
> Systems West Engineers
>
> 411 High Street
>
> Eugene, OR  97401-2427
>
> (541) 342-7210
>
> (541) 342-7220 (fax)
>
>
>
> *From:* equest-users-bounces at lists.onebuilding.org [mailto:
> equest-users-bounces at lists.onebuilding.org] *On Behalf Of *Vikram Sami
> *Sent:* Friday, March 05, 2010 2:01 PM
> *To:* eQUEST Users List
> *Subject:* [Equest-users] More about fans
>
>
>
> Same model – different fan question. Table G3.1.3.15 Gives you a part load
> performance table for VAV fan systems. Based on that, I created a
> performance curve (linear) for my VAV fan system that looks like this:
>
>
>
>
>
>
>
> Problem is when I use this as opposed to  the default curve that came out
> of the wizard, the fan energy doubles. The fan energy is still only 8% of
> the overall building load, so its not alarming. Does this mean that the
> default curve was way to low? Is the method above the way to model this
> performance curve?
>
>
>
> Thanks for your help
>
>
>
> *Vikram Sami,* LEED AP
> Direct Phone 404-253-1466 | Direct Fax 404-253-1366
>
> *L**ORD**, A**ECK** & S**ARGENT** A**RCHITECTURE**
> *1201 Peachtree Street NE, Suite 300, Atlanta, GA 30361
> Responsive Design · Technological Expertise · Exceptional Service
> Please visit our new website | www.lordaecksargent.com
>
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>
>
>
>
>
>
>
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