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% 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"
????: "??????"
????: 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
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
