[Bldg-sim] Spam:Re: System Fan Power in Appendix G

[James Hess]

One quick comment is that eQuest cannot currently model relief air  
fans. This would be a nice feature to add, but for now you would have  
to approximate separately in a spreadsheet, and then add to building  
electric meter as a direct load.

Regards,

JAH

James A. Hess, PE, CEM
Energy Engineer
TME, Inc.
Little Rock, AR
501-666-6776, x2308
501-351-4667 mobile

On Jan 22, 2009, at 10:31 AM, "Sam Mason" <sam.mason at atelierten.com>  
wrote:

> Section G3.1.2.8 says "if return or relief fans are specified in the
> proposed design, the baseline design shall also be modeled with fans
> serving the same function and sized for the baseline system supply fan
> air quantity less then minimum outdoor air, or 90% of the supply fan  
> air
> quantity, whichever is larger."
>
> This would lead me to believe that you need to specifically model
> return/exhaust/relief fans the same as supply fans and not group
> everything together.  Section G3.1.2.9 is written poorly because it
> calls out "supply CFM," but should be applicable to all types of fans.
>
> Comments?
>
> Sam
> --
> Sam Mason
> Atelier Ten
> sam.mason at atelierten.com
>
> -----Original Message-----
> From: bldg-sim-bounces at lists.onebuilding.org
> [mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Bill
> Talbert
> Sent: Tuesday, January 20, 2009 1:54 PM
> To: bldg-sim at lists.onebuilding.org; Kendra Tupper; Mike Kaufman; Ming
> Zeng
> Subject: Re: [Bldg-sim] System Fan Power in Appendix G
>
> Make sure you look at Addendum AC if you are using A90.1-2004. The
> calculation and pressure credits have changed, but it is still
> consistent with your Option 1 description.
>
>
>
> Bill Talbert, PE, LEED(r) AP
> Mechanical Systems
> Phone: (608) 441-6677
> E-mail: btalbert at aeieng.com
>
> Affiliated Engineers Inc.
> 5802 Research Park Blvd.
> Madison, WI. 53719
> Tel. (608) 238-2616
> Fax. (608) 238-2614
>
>
>>>> Kendra Tupper <ktupper at rmi.org> 1/20/2009 12:42 PM >>>
> Option 1 - the user's manuals are a bit more clear, and specify that  
> the
> its is the supply cfm that should be used to calculate the fan power.
> This fan power includes supply, return and exhaust.
>
>
> On 1/20/09 11:29 AM, "Zeng, Ming" <mzeng at leoadaly.com> wrote:
>
>
> My understanding is option 1. The fan energy in that formula is the  
> sum
> of all the fan horse power. Search the board, I think there is a
> previous email from Michael Rosenberg talking about the fan energy.  
> Hope
> this helps.
>
>
> Ming Zeng, PE, LEED(r) Accredited Professional
>
> Mechanical Engineer
>
>
>
>
> 730 Second Avenue South, Suite 1100, Minneapolis, MN 55402-2455
>
> T 612.338.8741    F 612.338.4840    D 612.341.9539
>
> www.leoadaly.com <http://www.leoadaly.com>     MZeng at leoadaly.com
>
> Please consider the environment before printing.
>
> From: bldg-sim-bounces at lists.onebuilding.org
> [mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Mike
> Kaufman
> Sent: Tuesday, January 20, 2009 12:16 PM
> To: bldg-sim at lists.onebuilding.org
> Subject: [Bldg-sim] System Fan Power in Appendix G
>
> Hi All,
>
> I have a specific question about using Appendix G3.1.2.9 to calculate
> baseline system fan power (I have already searched previous posts and
> could not find the answer I'm looking for).  So, the Appendix G  
> section
> reads as follows: System fan electrical power for supply, return,
> exhaust, and relief (excluding power to fan powered VAV boxes) shall  
> be
> calculated using the following formulas.  I understand the formulas,
> which essentially use a fan CFM to determine a brake horsepower BHP,
> which is then used to calculate the fan power (Watts), but my question
> is this:  Supposing you have an HVAC system with supply, return, and
> small exhaust fans (in restrooms, for example) - how do you calculate
> the power to each fan?
>
> Option 1:  Use your supply fan cfm to calculate a power, say it  
> comes to
> 10 kW, and use this as your total "system" fan power.  This 10 kW,  
> being
> your whole system power, is then distributed among all of your system
> fans however you desire (For example, supply fan power = 5 kW, return
> fan power = 4 kW, exhaust fan power = 1 kW, for a total of 10 kW for  
> the
> fan system)
>
> OR
>
> Option 2:  Use each supply, return, and exhaust fan cfm to separately
> calculate an individual kW for each fan (For example, supply fan  
> power =
> 10 kW using the supply cfm, return fan power = 9 kW using the return
> cfm, exhaust fan power = 1 kW using the exhaust cfm, for a total of 20
> kW for the whole fan system)
>
> Obviously, you will have much more fan energy in a baseline system
> calculating fan power with Option 2.  Does anyone have a specific
> example they can share of a fan system calculation that was accepted  
> by
> USGBC for an EAc1 energy model?
>
> Thanks for your help!
> Mike
>
>
>      Mike Kaufman, Building Performance Engineer 130 W. 5th Avenue,
> Denver, CO 80204 (NOTE NEW ADDRESS) t 303.278.1532x206 | f  
> 303.278.8533
> | ambient-e.com <http://www.ambient-e.com/>
>
>
>
>
>
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