[Bldg-sim] SEER and Fan Energy

[Kingsley, Michael L.]

Vikram,

 

I agree with your assessment of the way eQUEST deals with packaged
systems fan energy and cooling efficiency through the wizard.  I always
end up using the detailed interface instead though.

 

Thanks for sending the spreadsheet.  I did look at it and made a few
edits that I will describe below.  I would also appreciate any feedback
from anyone.

 

*         I edited the lookup table to find the next size up motor hp
based on bhp; this is to find the motor efficiency only

*         I used different fan cfm for the example units you listed (400
cfm/ton)

*         I changed some of the units of measure to kW instead of Watts
(just personal preference)

*         The main change I made was to deal with fan heat.  Rated
capacity and efficiency are based on total input power and net cooling
output.  So in order to deal with the fan separately we need to subtract
the fan input electricity from the unit electricity input (as was done),
but we also need to subtract the fan heat from the net cooling capacity
to arrive at the gross cooling capacity.  The gross EER and EIR are then
calculated with fan input and heat removed.  After eQUEST adds the fan
input electricity and fan heat then you end up with the rated efficiency
(if you're at rated conditions).  I added columns related to fan heat
and adjusted the EER and EIR equations.  You can change Fan Heat Frac.
To zero (as if the fan motor is outside of the unit) to see the impact.


 

Hopefully this is of help to some.

 

Best regards,

 

Mike

 

Michael L. Kingsley, PhD, PE, CPMP, LEED AP

Senior Engineer/Project Manager | Energy Efficiency & Demand Response

SAIC Energy, Environment & Infrastructure, LLC

office: 315.434.7205 | mobile: 315.373.4081

www.saic.com/EEandI <http://www.saic.com/EEandI> 

 

 

 

From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Sami,
Vikram
Sent: Wednesday, January 30, 2013 3:52 PM
To: RobertWichert; Haynes, Glenn
Cc: bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] SEER and Fan Energy

 

If I understand the quandary you are referring to packaged systems where
the fan energy is included in the package. In eQUEST - if you select the
EER rating (or SEER rating) in the wizard, then its my understanding
that the program does this automatically for you. However, if you are
using the 90.1 methodology, then you probably want to go beyond the
wizard. I developed the attached spreadsheet to parse out the energy by
fan and cooling - feel free to use it. I would appreciate feedback from
anyone willing to check my math and methodology. 

 

 

Vikram Sami, LEED AP BD+C

Sustainable Design Analyst

1315 Peachtree St. NE, Atlanta, GA 30309

t: 404-443-7462    f: 404.892.5823       e: vikram.sami at perkinswill.com
www.perkinswill.com <http://www.perkinswill.com/> 

Perkins+Will.  Ideas + buildings that honor the broader goals of society

 

-----Original Message-----
From: bldg-sim-bounces at lists.onebuilding.org [
mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of
RobertWichert
Sent: Wednesday, January 30, 2013 3:15 PM
To: Haynes, Glenn
Cc: bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] SEER and Fan Energy

 

That makes sense, Glenn.  So it's a manual adjustment to the EIR.  In
Energy Pro, which I use a lot, that can be done by using the
"Compressor/Condenser Power" option and then adding the fan power in
separately, but only for systems over five tons.  Smaller systems are
stuck with SEER.

 

I think the problem I'm facing is that Energy Pro uses SEER for small
systems, not EER/EIR.

 

 

 

 

Robert Wichert P.Eng. LEED AP BD&C

+1 916 966 9060

FAX +1 916 966 9068

 

 

 

 

 

 

 

===============================================

 

On 1/30/2013 11:31 AM, Haynes, Glenn wrote:

> Robert,

> 

> First you must estimate the EIR from the SEER to input unit efficiency
in DOE2.  The conversion depends on the system type and other things,
but for starters you can multiply SEER by something like 0.89 to
estimate EER (then EIR = 3.413/EER, which I am sure you already know) if
you don't have something better.

> 

> When I do a residential model I take the fan power (at full speed) out
of the EIR and use the adjusted EIR for the modeled AC unit.  Then I add
the fan power to the input stream through SUPPLY-KW/FLOW.  That way you
get a truer unit power.

> 

> Best regards,

> for KEMA USA, Inc.

> 

> Glenn C. Haynes, PE

> Senior Engineering Consultant

> DNV KEMA Energy & Sustainability

> 

> Tel: (615) 783-2187

> 3200 West End Avenue, Suite 500

> Nashville, TN 37203

> USA

> glenn.haynes at kema.com <mailto:glenn.haynes at kema.com> 

> Please visit our website: www.dnvkema.com <http://www.dnvkema.com> 

> 

> This message may contain confidential or private information.  If you
are not the addressee, please return the message to its sender and
delete it from your files.  Please consider the environment before
printing this email.

> 

> 

> 

> -----Original Message-----

> From: bldg-sim-bounces at lists.onebuilding.org [
mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of
RobertWichert

> Sent: Wednesday, January 30, 2013 8:48 AM

> To: bldg-sim at lists.onebuilding.org

> Subject: [Bldg-sim] SEER and Fan Energy

> 

> This forum has discussed fan energy before, and since that time I have

> grappled with the concept of fan power, specifically how to avoid
double

> counting fan power since even indoor fans are included in SEER
ratings.

> 

> I suppose that I should start by confirming that indoor supply and

> return fans are included in SEER ratings.  I have read the DOE 49 CFR

> Pt. 430, Subpt. B, App. M UNIFORM TEST METHOD FOR MEASURING THE ENERGY

> CONSUMPTION OF CENTRAL AIR CONDITIONERS AND HEAT PUMPS.  It seems
clear

> in that method that indoor fans are included in the power and energy

> calculations.  If not, please let me know what I am missing.

> 

> OK, if indoor supply and return fans are included in the SEER rating,

> then why would we put additional fan energy into our calculations?
Does

> EQuest, EnergyPro, E+, and all the rest do some math to subtract this

> out, and if so, how is that done?

> 

> Sorry for the basic question, but I have thought about this a lot and

> haven't reached a comfortable solution.  At one point I thought that
the

> SEER calculation did not account for indoor fans, but I now find that
to

> be wrong.

> 

> 

> Your thoughts are appreciated.

> 

> 

> 

 

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