[Equest-users] Baseline Fan power calculation

[vamshi ranga]

Hi Cam,

This is so nice of you, I really appreciate your efforts in for clearing my
concepts and helping me out. This is really useful.

Here by I want to share some of the very useful links for energy modelers.

http://energy-models.com/tools/leed-fan-calculator
http://www.gbci.org/files/leedonline/Advanced_Energy_Modeling_for_LEED_V2_1c.pdf
http://www.rmi.org/ModelingTools
http://www.rmi.org/Content/Files/EMIT%20User's%20Guide.pdf

Thank you Mr. Nick, if initial clarification.

Thank you,
Vamshi




On Tue, Mar 26, 2013 at 6:28 PM, Cam Fitzgerald <cam at energyopportunities.com
> wrote:

> So you are still confused. Hope this clarifies the process for you:****
>
> ** **
>
> 1. Example baseline fan power distribution calculations (other methods are
> acceptable, but this is one of the most common approaches)****
>
> ** **
>
> Proposed system:****
>
> Total fan kW (20+18+2.5=40.5 kW)****
>
> Design supply fan percent of total power (20/40.5=0.494)****
>
> Design return fan percent of total power (18/40.5=0.444)****
>
> Design exhaust fan percent of total power (2.5/40.5=0.062)****
>
> ** **
>
> Baseline supply airflow calculated per Section G3.1.2.8 (Note: rarely a
> nice round number, but I will use your number for this example) – 30,000 cfm
> ****
>
> Assuming the baseline system is VAV (system types 5 – 8), and using a
> pressure drop adjustment factor of 0.5 IWC (MERV 12 filter) , calculated
> system fan power is 34.196 kW****
>
> Using the same ratios as the Proposed system, the Baseline fan power would
> be: 16.893 kW supply; 15.183 kW return; and 2.120 kW exhaust.
> (16.893+15.183+2.12=34.196)****
>
> You can use this power to determine the kW/cfm for each fan.****
>
> ** **
>
> 2. The supply fan may slightly increase the supply temperature, but this
> is usually minimal and does not significantly impact the supply air
> temperature.****
>
> 3. The baseline case prior to rotation should be used.****
>
> 4. See response to #1.****
>
> ** **
>
> Good luck!****
>
> ** **
>
> Cam****
>
> ** **
>
> *From:* vamshi ranga [mailto:vamshiranga at gmail.com]
> *Sent:* Tuesday, March 26, 2013 8:07 AM
> *To:* Cam Fitzgerald
> *Cc:* Nick Caton; equest-users at lists.onebuilding.org
>
> *Subject:* Re: [Equest-users] Baseline Fan power calculation****
>
> ** **
>
> Hi,****
>
> ** **
>
> Thanks, but it is difficult to understand (some confusion). Let's say the
> Proposed system has following specifications****
>
> ** **
>
> Supply fan cfm = 40000****
>
> Supply fan Wattage = 20000****
>
> Return fan cfm = 35000****
>
> Return fan Wattage = 18000****
>
> Filter used = MERV 12****
>
> Exhaust fan cfm = 5000****
>
> Exhaust fan Wattage = 2500****
>
> ** **
>
> And Baseline (0 deg orientation) has following specifications when
> simulated with default fan kW/cfm and 20 deg F difference,****
>
> ** **
>
> Supply fan cfm = 30000****
>
> Supply fan Wattage = 15000****
>
> Return fan cfm = 25000****
>
> Return fan Wattage = 13000****
>
> ** **
>
> 1. Please tell me how to distribute kW/cfm in basecase and from where will
> I get baseline default exhaust specification?****
>
> 2. Won't the change in baseline when we input calculated value in eQUEST
> due to heat gain****
>
> 3. Should we take all the 4 orientations average cfm for calculating
> baseline cfms****
>
> 4. Tell me how to calculate baseline fan power from above values****
>
> ** **
>
> If, this example is confusing. I request you to give your own example for
> understanding.****
>
> I have been having doubt related to fan power calculation. I am eager to
> learn how to do it properly to avoid any GBCI comments.****
>
> ** **
>
> Your valuable time put in resolving my doubt is appreciated.****
>
> ** **
>
> Thanks,****
>
> Vamshi.****
>
> ** **
>
> ** **
>
> On Tue, Mar 26, 2013 at 3:23 PM, Cam Fitzgerald <
> cam at energyopportunities.com> wrote:****
>
> All,****
>
>  ****
>
> It seems there is much confusion on this issue. The Proposed fans are all
> modeled explicitly (with the fan power as designed). In the Baseline case
> each HVAC system fan power (Section G3.1.2.9)  is calculated using the
> supply airflow (Section G3.1.2.8) based on 20 F space to supply air
> temperature difference. If the Proposed system uses multiple fans, then the
> calculated system fan power is distributed among the fans in the Proposed
> design. Appendix G does not provide any guidance for how this power should
> be distributed among the system fans in the Baseline system, but usually
> projects use the same proportion of the total system fan power as the
> Proposed design. All the fan power can be modeled as a single supply fan,
> but that will apply all the heat gain from the fan to the supply airstream
> which may not be realistic for large systems. Note that exhaust fans in the
> Proposed design that operate continuously during occupied periods are
> considered part of the system and their power is included in the calculated
> Baseline fan power. Exhaust fans that operate intermittently are considered
> a process load and must be modeled identically in both cases. If the
> Proposed process exhaust fan motor is larger than one HP, the motor
> efficiency is regulated by  Section 10 and savings may be claimed for using
> high efficiency motors as compared to the minimum efficiency from Table
> 10.8.****
>
>  ****
>
> Hope this helps!****
>
>  ****
>
> Cam Fitzgerald****
>
>  ****
>
> Energy Opportunities/a 7group company****
>
>  ****
>
>  ****
>
>  ****
>
>  ****
>
> *From:* equest-users-bounces at lists.onebuilding.org [mailto:
> equest-users-bounces at lists.onebuilding.org] *On Behalf Of *vamshi ranga
> *Sent:* Tuesday, March 26, 2013 3:27 AM
> *To:* Nick Caton
> *Cc:* equest-users at lists.onebuilding.org
> *Subject:* Re: [Equest-users] Baseline Fan power calculation****
>
>  ****
>
> Dear Nick Caton,****
>
>  ****
>
> Thank you very much for valuable inputs, from this it is clear that, ****
>
>  ****
>
> 1. However there are different motors used in Proposed case for supply,
> return and exhaust with different kW/cfm, we need to use one single motor
> in with one kW/cfm in baseline case****
>
> 2. In EAp2 Section 1 4 Tables of LEED under "Table 1.4.2", it asks
> for separate wattage of supply, return and exhaust fans in baseline case,
> So, there we need to enter as "Not Applicable"****
>
>  ****
>
> Please let me know if my understanding is wrong.****
>
>  ****
>
> Thanks,****
>
> Vamshi.****
>
>  ****
>
> On Mon, Mar 25, 2013 at 8:04 PM, Nick Caton <ncaton at smithboucher.com>
> wrote:****
>
> Hi Vamshi,****
>
>  ****
>
> I advise carefully reviewing the footnotes under Table 6.5.3.1.1A, which
> include procedure for determining baseline fan power adjustments.****
>
>  ****
>
> 1.       Pfan represents the sum power of all fans in a given baseline
> system (with exception to baseline systems #6/#8, fan powered VAV boxes).*
> ***
>
> 2.       Again, there is not a separate supply/return power calculation
> (see answer #1).  You can however account for adjustments present in
> separate airstreams from the proposed design.  ****
>
> 3.       Probably not.  Review the difference between CFMS and CFMDcarefully at the cited Table.  A CFM quantity representing the airflow each
> element encounters (CFMD) should be applied against each pressure drop
> adjustment, not an ‘aggregate’ of supply+return.  ****
>
>  ****
>
> You may also find the attached resource published by 7group helpful to
> cement your procedural understanding of how to arrive at the sum total for
> “A.”  ****
>
>  ****
>
> Regards,****
>
>  ****
>
> ~Nick****
>
> [image: cid:489575314 at 22072009-0ABB]****
>
> * *****
>
> *NICK CATON, P.E.*****
>
> SENIOR ENGINEER****
>
>  ****
>
> Smith & Boucher Engineers****
>
> 25501 west valley parkway, suite 200****
>
> olathe, ks 66061****
>
> direct 913.344.0036****
>
> fax 913.345.0617****
>
> www.smithboucher.com* *****
>
>  ****
>
> *From:* equest-users-bounces at lists.onebuilding.org [mailto:
> equest-users-bounces at lists.onebuilding.org] *On Behalf Of *vamshi ranga
> *Sent:* Monday, March 25, 2013 8:17 AM
> *To:* equest-users at lists.onebuilding.org
> *Subject:* [Equest-users] Baseline Fan power calculation****
>
>  ****
>
> Hi All,****
>
>  ****
>
> I have a doubt regarding calculating fan power as per ASHRAE 90.1-2007.***
> *
>
>  ****
>
> My proposed system has, supply return and exhaust fans separately with kW
> and cfm mentioned for each fan.****
>
>  ****
>
> So, for calculating baseline fan power, ****
>
>  ****
>
> 1. should I calculate it separately for each fan type? ****
>
> 2. can I take pressure drop adjustment both in supply and return fan power
> calculation?****
>
> 3. should I sum all the cfms of supply, return and exhaust and than apply
> pressure drop adjustments to aggregated cfm.****
>
>  ****
>
> Kindly help me out in solving the doubt. If you have any example fan power
> calculations, or web links those could guide me regarding this, plz do
> share them.****
>
>  ****
>
> Thanks in advance.****
>
>  ****
>
> Regards,****
>
> Vamshi.****
>
>  ****
>
> ** **
>
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