[Equest-users] Efficiency conversions revisited

Thu Jul 9 14:41:06 PDT 2015

I haven’t heard any rumors of GBCI enforcing/requesting 90.1-2013 be
utilized… yet.

Based on the pace of LEED’s 90.1 adoption, it seems to me by the time LEED
gets around to 90.1-2013 ASHRAE may well have revised/fleshed out further
those passages (I’m expecting the Ec/Et issue for large boilers to
eventually be formally addressed eventually).  Until that time comes I’m
pretty sure it’s up to the modeler’s discretion to use any method that is
considerate of the requirements in play and applied consistently between
projects.

I noted you’re talking about “actual” equipment with a cutsheet to
reference:  GBCI shouldn’t have a problem with you keeping fan energy in
your cooling/heating EIR inputs if the actual system fan does not operate
independently of the remote unit.  Any effort to pull the fan energy out of
your cooling/heating EIR inputs by such curves/equations would net the same
results and wouldn’t be meaningful.

My copy of 90.1-07 is boxed up right now so I can’t directly cite, but the
same passage mandating continuous fan operation during occupied hours for
baseline systems says not to pull fan energies out for cycling systems… all
that passage is specific to baseline systems but the framework should carry
over to allowing you to simulate the proposed systems in the same fashion.
Keep in mind that passage and the new stuff Maria copied us on below is all
specific to BASELINE systems and isn’t directing how to simulate the
proposed/actual counterparts ;).

Regards,

~Nick

*NICK CATON, P.E.*
*Owner*

*Caton Energy Consulting*
  1150 N. 192nd St., #4-202

  Shoreline, WA 98133
  office:  785.410.3317

www.catonenergy.com

*From:* Jones, Christopher [mailto:Christopher.r.Jones at wspgroup.com]
*Sent:* Thursday, July 09, 2015 12:10 PM
*To:* Maria Karpman; 'Nicholas Caton'; 'Equest-users'
*Subject:* Efficiency conversions revisited

I am hoping for some insight for modeling the efficiencies of split system
heat pumps and other such stand alone systems.

In this case, the shop drawing provides the ARI rated efficiencies which
include the fan power.  But this shop drawing does not provide the fan
motor power.

In the past I would convert the rated EER to COP using COP = EER/3.4121 and
I would assume no fan power as the rating includes the fan power.  But this
project is being submitted to the USGBC and I am worried that the GBCI may
have an issue with this.

As Maria pointed out, 90.1-2013 now provides the formula to convert EER to
COP, removing the fan power.  The baseline fan power would be calculated
using the formulas in G3.1.2.10.  Would it be best to use the same method
to calculate the proposed case fan power and COP?

[image: cid:image003.png at 01D09C46.E75BA0D0]

*Christopher Jones,* P.Eng.
Senior Engineer

*WSP Canada Inc.*

2300 Yonge Street, Suite 2300

Toronto, ON M4P 1E4
T +1 416-644-4226

F +1 416-487-9766

C +1 416-697-0065

www.wspgroup.com

*From:* Equest-users [mailto:equest-users-bounces at lists.onebuilding.org
<equest-users-bounces at lists.onebuilding.org>] *On Behalf Of *Maria Karpman
*Sent:* Tuesday, May 26, 2015 10:18 AM
*To:* 'Nicholas Caton'; 'Equest-users'
*Subject:*: Reply： The problem of minimum equipment efficiency requirement
of Ashrae 90.1-2007

As far as SEER to EER and HSPF to COP conversions, 90.1 2013 finally
provided these in G3.1.2.1, along with the formulas for extracting fan
power from efficiency ratings:

*G3.1.2.1 Equipment Efficiencies. *All HVAC equipment

in the baseline building design shall be modeled at the mini-

mum efficiency levels, both part load and full load, in accordance

with Section 6.4. Chillers shall use Path A efficiencies

as shown in Table 6.8.1-3 where efficiency ratings include

supply fan energy, the efficiency rating shall be adjusted to

remove the supply fan energy. For Baseline HVAC Systems 1,

2, 3, 4, 5, and 6, calculate the minimum COP*nfcooling *and

COP*nfheating *using the equation for the applicable performance

rating as indicated in Tables 6.8.1-1 through 6.8.1-4.

Where a full- and part-load efficiency rating is provided in

Tables 6.8.1-1 through 6.8.1-4, the full-load equation below

shall be used:

COP*nfcooling *= 7.84E-8 × EER × *Q *+ 0.338 × EER

COP*nfcooling *= –0.0076 × SEER2 + 0.3796 × SEER

COP*nfheating *= 1.48E-7 × COP*47 *× *Q *+ 1.062 × COP*47*

(applies to heat-pump heating efficiency only)

COP*nfheating *= –0.0296 × HSPF2 + 0.7134 × HSPF

where COP*nfcooling *and COP*nfheating *are the packaged HVAC

equipment cooling and heating energy efficiency, respectively,

to be used in the baseline building, which excludes

supply fan power, and *Q *is the AHRI-rated cooling capacity

in Btu/h.

EER, SEER, COP, and HSPF shall be at AHRI test conditions.

Fan energy shall be modeled separately according to

Section G3.1.2.10.

Hope this helps,

Maria

-- 

*Maria Karpman *LEED AP, BEMP, CEM

________________

Karpman Consulting

www.karpmanconsulting.net

Phone 860.430.1909

41C New London Turnpike

Glastonbury, CT 06033

*From:* Equest-users [mailto:equest-users-bounces at lists.onebuilding.org
<equest-users-bounces at lists.onebuilding.org>] *On Behalf Of *Nicholas Caton
*Sent:* Friday, May 29, 2015 11:17 AM
*To:* 赵永青; Equest-users
*Subject:* Re: [Equest-users] RE: Reply： The problem of minimum equipment
efficiency requirement of Ashrae 90.1-2007

Yeah same for my case (not AFUE), though that’s good thinking!

When I do have an AFUE boiler requirement, I have found it easier to stick
with the default library curves / standby inputs & to determine the full
load HIR with the following equations:

HIR = f(AFUE): *  [Reference: California Energy Commission's 2005
"Nonresidential Alternative Calculation Method (ACM) Approval
Manual"]*

                For single packaged central furnace (baseline system
#3):                            HIR =
(.005163*AFUE+0.4033)^-1

                For Boilers where 75 ≤ AFUE < 80 (Baseline systems #1, #5
&#7):               HIR = (0.1*AFUE+72.5)^-1*100

                For Boilers where 80 ≤ AFUE < 100 (Baseline systems #1, #5
&#7):            HIR =
(0.875*AFUE+10.5)^-1*100

For completeness, here are the other equations I keep handy for converting
other seasonal efficiencies to steady-state inputs:

EER=f(SEER):      *[Reference: NREL Building America House Simulation
Protocol (Revised), citing Wassmer, M. (2003). A Component-Based Model for
Residential Air Conditioner and Heat Pump Energy Calculations.]*

(AC) (Baseline Systems #1, #3, #5 & #6):               EERNET=
-0.0182*SEER^2 + 1.1088*SEER

(HP-cooling) (Baseline Systems #2 & #4):              EERNET = -0.02*SEER^2
+ 1.1268*SEER

COP=f(HSPF):    *[Reference: Wassmer, M. (2003). A Component-Based Model
for Residential Air Conditioner and Heat Pump Energy Calculations. Masters
Thesis, University of Colorado at Boulder.]*

(HP-heating) (Baseline Systems #2 & #4):             COPNET =
-0.0255*HSPF^2 + 0.6239*HSPF

IIRC, each of the above cited references determines these equations based
on a survey of real-world equipment from various manufacturers in order to
plot a quadratic trendline.  That trendline establishes the relationship
between steady state full load efficiency and the associated seasonal
efficiency rating.  In time (or until such equations are added to Appendix
G to regulate how modelers approach seasonal efficiency requirements), it
may be appropriate to seek out similar research to update these equations
every so often, but for the present and past couple of years I have had
zero problems using this family of equations for my LEED reviews.

~Nick

*NICK CATON, P.E.*
*Owner*

*Caton Energy Consulting*
  1150 N. 192nd St., #4-202

  Shoreline, WA 98133
  office:  785.410.3317

www.catonenergy.com

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