=?gb18030?b?u9i4tKO6UkU6ICC72Li0o7ogILvYuLSjulJF?= =?gb18030?q?=3A__Reply=A3=BA_The_problem_of_minimum_equipment_efficiency_?=

3 posts / 0 new
Last post

I also find the definition of AFUE in manual , but the boiler capacity of my project( a very big project) is larger than 88kW, So the efficiency of boiler should be 80%(Ec),not 80%(AFUE).

------------------
Yongqing Zhao
Changsha Green Building & Energy Saving Technology CO.,LTD
NO.438,Shaoshan Road,Changsha,Hunan,China
Telephone:13574805636
Email:zhaoyongqing1987 at 126.com
503271081 at qq.com

------------------ ???????? ------------------
??????: "Lapierre, Patrick";
;
????????: 2015??5??25??(??????) ????8:23
??????: "??????"<503271081 at qq.com>; "Daniel Knapp"; "Nicholas Caton";
????: "equest-users at lists.onebuilding";
????: RE: [Equest-users] ?????? ??????RE: Reply?? The problem of minimum equipment efficiency requirement of Ashrae 90.1-2007

I agree with Nick that removing the default start-up times in the baseline seems inappropriate and that it should also be done in the proposed design if done in the reference (when the baseline performance is based on Et)

I didn??t see any model attached so I couldn??t check but could it be possible the boiler size falls into the smaller category of table 6.8.1F where it??s efficiency is defined as 80% AFUE? The comment of the reviewer would make much more sense if it was the case, since 80% AFUE is different from 80% Et. In my understanding, 80% AFUE refers to a global annual efficiency of 80% and 80% Et refers to 80% efficiency at peak load which would result in a global annual efficiency lower than 80% when you consider part loads and boiler cycling.

I would deem as correct the reviewer??s comment if the boiler size falls into the 80% AFUE category.

??The AFUE differs from the true 'thermal efficiency' in that it is not a steady-state, peak measure of conversion efficiency, but instead attempts to represent the actual, season-long, average efficiency of that piece of equipment, including the operating transients.[1] ??
1^ Systems and Equipment volume of the ASHRAE Handbook, ASHRAE, Inc., Atlanta, GA, USA, 2004

However, if your boiler size falls into the Et or Ec category then, as everyone else here, I find the comment somewhat strange.

Patrick Lapierre_ing.
plapierre at bpa.ca

De : Equest-users [mailto:equest-users-bounces at lists.onebuilding.org] De la part de ???
Envoy?? : 24 mai 2015 20:42
?0?8 : Daniel Knapp; Nicholas Caton
Cc : equest-users at lists.onebuilding
Objet : [Equest-users] ?????? ??????RE: Reply?? The problem of minimum equipment efficiency requirement of Ashrae 90.1-2007

Hi,Dan

The comment is a full version,no context missing!I also feel very strange with it.

------------------
Yongqing Zhao
Changsha Green Building & Energy Saving Technology CO.,LTD
NO.438,Shaoshan Road,Changsha,Hunan,China
Telephone:13574805636
Email:zhaoyongqing1987 at 126.com
503271081 at qq.com

------------------ ???????? ------------------
??????: "Daniel Knapp";;
????????: 2015??5??25??(??????) ????1:34
??????: "Nicholas Caton";
????: "??????"; "Julien Marrec"; "equest-users at lists.onebuilding";
????: Re: [Equest-users] ??????RE: Reply?? The problem of minimum equipment efficiency requirement of Ashrae 90.1-2007

I'm with Nick. I find the GBCI reviewer comment as reported to be a bit strange and I wonder if there is some context missing. Is it possible that the seasonal efficiency was much lower than 80% in the baseline, suggesting either oversizing of the baseline boilers or a curve that is different from the proposed curve?

Best,
Dan

??
Sent from my phone

On May 24, 2015, at 11:38 AM, Nicholas Caton wrote:
I??m happy you are arriving at the same result, however to be clear I do not think the reviewer is correct to assert the prescribed efficiency is anything other than the full-load efficiency.

Follow the cited Test Procedure CFR 431 led me to:
https://www.law.cornell.edu/cfr/text/10/431.86

??? 431.86 (c) (3) (ii) Thermal Efficiency. Use the calculation procedure for the thermal efficiency test specified in Section 11.1 of the HI BTS-2000, Rev 06.07 (incorporated by reference, see? 431.85).??

I then found the referenced HI standard here (PDF link): https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CB8QFjAA&url=https%3A%2F%2Flaw.resource.org%2Fpub%2Fus%2Fcfr%2Fibr%2F004%2Fhi.BTS-2000.2007.pdf&ei=R-dhVZr3FoffoASKxYC4Bw&usg=AFQjCNGb2HahzcO_Q-BftBzCugY5sPtifg&sig2=k1fojL9GcpjnN6T2fdzOug

In that standard, section 5 reads:
5.0 TYPES OF TESTS
5.1 Thermal Efficiency Test
Shall consist of a test point conducted at 100% ?? 2% of the nameplate boiler input. The test shall
yield a complete accounting of the energy input in terms of output and losses.
5.2 Combustion Efficiency Test
Shall consist of a test point conducted at 100% ?? 2% of the input to the boiler and shall yield an
accounting of energy input in terms of products of combustion only.

From this, it is clear Et and Ec as prescribed by 90.1 are only the efficiencies as measured at full load. The test procedures following under section 9 deliberately exclude the effects of warmup/standby (equipment is made to warm up and arrive at the mandated operating conditions prior to measurements).

Section 11.1 of the standard prescribes all the calculations required, including Et = 100*QOUT / QIN , however the preceding sections makes clear we are in no way standardizing part load performance or warmup/standby performance.

Rounding back to 90.1?? section 6.4.1.1 further cements the notion (??packaged boilers?? fall under 1992 EPACT):

All this reinforces the point that 90.1 simply does not prescribe part load performance for baseline boilers. To perform a simulation in compliance with Appendix G the onus is upon the energy modeler to make reasonable, defensible assumptions on that front. I don??t see how forcing full-load efficiencies at all part-load conditions and removing standby/startup operation energies is more reasonable or reflects reality better than the defaults.

If this is a new GBCI position they plan to hard-line on, then I would speculate it would be equally fair (albeit far more unrealistic for condensing cases) to give your proposed boilers the same treatment?? extra work for a step backwards from reality???

Thoughts?

~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

=?GB2312?B?1dTTwMfg?='s picture
Joined: 2013-07-05
Reputation: 0

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
): HIR = (0.1*AFUE+72.5)^-1*100

For Boilers where 80 ? AFUE < 100 (Baseline systems #1, #5
): 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

*From:* Equest-users [mailto:equest-users-bounces at lists.onebuilding.org] *On
Behalf Of *???
*Sent:* Monday, May 25, 2015 6:24 AM
*To:* Equest-users
*Subject:* [Equest-users] ???RE: ??? ???RE: Reply? The problem of minimum
equipment efficiency requirement of Ashrae 90.1-2007

I also find the definition of AFUE in manual , but the boiler
capacity of my project( a very big project) is larger than 88kW, So
the efficiency of boiler should be 80%(Ec),not 80%(AFUE).

------------------
*Yongqing Zhao*
*Changsha Green Building & Energy Saving Technology CO.,LTD*
NO.438,Shaoshan Road,Changsha,Hunan,China
Telephone:13574805636
Email:zhaoyongqing1987 at 126.com
503271081 at qq.com

------------------ ???? ------------------
*?**??**:* "Lapierre, Patrick";
;
*?**?**??**:* 2015?5?25?(???) ??8:23
*???**:* "???"<503271081 at qq.com>; "Daniel Knapp" *??**:* "equest-users at lists.onebuilding" *?**?**:* RE: [Equest-users] ??? ???RE: Reply?
The problem of minimum equipment efficiency requirement of Ashrae 90.1-2007

I agree with Nick that removing the default start-up times in the
baseline seems inappropriate and that it should also be done in the
proposed design if done in the reference (when the baseline
performance is based on
*Et*)

I didn?t see any model attached so I couldn?t check but could it be
possible the boiler size falls into the smaller category of table
6.8.1F where it?s efficiency is defined as 80% AFUE? The comment of
the reviewer would make much more sense if it was the case, since
*80% AFUE* is different from *80% Et*
. In my understanding, 80% AFUE refers to a global annual efficiency
of 80% and 80% E
t
refers to 80% efficiency at peak load which would result in a global
annual efficiency lower than 80% when you consider part loads and
boiler cycling.

I would deem as correct the reviewer?s comment if the boiler size
falls into the 80% AFUE category.

?
The AFUE differs from the true 'thermal efficiency' in that it is not
a steady-state, peak measure of conversion efficiency, but instead
attempts to represent the actual, season-long, average efficiency of
that piece of equipment, including the operating transients.
[1] ?
1*^* Systems and Equipment volume of the *ASHRAE Handbook*
, ASHRAE, Inc., Atlanta, GA, USA, 2004

However, if your boiler size falls into the *Et* or *Ec *
category then, as everyone else here, I find the comment somewhat strange.

*Patrick* *Lapierre**_ing.*
plapierre at bpa.ca

*De :* Equest-users [mailto:equest-users-bounces at lists.onebuilding.org
] *De la part de* ???
*Envoy? :* 24 mai 2015 20:42
*? :* Daniel Knapp; Nicholas Caton
*Cc :* equest-users at lists.onebuilding
*Objet :* [Equest-users] ??? ???RE: Reply?
The problem of minimum equipment efficiency requirement of Ashrae 90.1-2007

Hi,Dan

The comment is a full version,no context missing!I also feel very
strange with it.

------------------
*Yongqing Zhao*
*Changsha Green Building & Energy Saving Technology CO.,LTD*
NO.438,Shaoshan Road,Changsha,Hunan,China
Telephone:13574805636
Email:zhaoyongqing1987 at 126.com
503271081 at qq.com

------------------ ???? ------------------
*???**:* "Daniel Knapp";;
*????**:* 2015?5?25?(???) ??1:34
*???**:* "Nicholas Caton";
*??**:* "???"; "Julien Marrec"<
julien.marrec at gmail.com>; "equest-users at lists.onebuilding"<
equest-users at lists.onebuilding.org>;
*??**:* Re: [Equest-users] ???RE: Reply?
The problem of minimum equipment efficiency requirement of Ashrae 90.1-2007

I'm with Nick. I find the GBCI reviewer comment as reported to be a
bit strange and I wonder if there is some context missing. Is it
possible that the seasonal efficiency was much lower than 80% in the
baseline, suggesting either oversizing of the baseline boilers or a
curve that is different from the proposed curve?

Best,
Dan

?
Sent from my phone

Nicholas Caton's picture
Offline
Joined: 2014-12-09
Reputation: 0

I would not use a flat curve for the baseline boiler because the baseline boiler is ?natural draft? (G3.1.2.2), and natural draft boilers do not operate at full load efficiency at part load conditions. I think the safest approach is to use part load boiler performance curves from COMNET Modeling Guide p.201 (copied below and found at http://www.comnet.org/mgp/content/boilers?purpose=0). This resource is directly referenced by USGBC as the source for modeling assumptions http://www.usgbc.org/resources/comnet-commercial-buildings-energy-modeling-guidelines.

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 COPnfcooling and

COPnfheating 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:

COPnfcooling = 7.84E-8 ? EER ? Q + 0.338 ? EER

COPnfcooling = ?0.0076 ? SEER2 + 0.3796 ? SEER

COPnfheating = 1.48E-7 ? COP47 ? Q + 1.062 ? COP47

(applies to heat-pump heating efficiency only)

COPnfheating = ?0.0296 ? HSPF2 + 0.7134 ? HSPF

where COPnfcooling and COPnfheating 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

Maria Karpman's picture
Offline
Joined: 2011-09-30
Reputation: 0