[Equest-users] 转发：RE: Reply： The problem of minimum equipment efficiency requirement of Ashrae 90.1-2007
赵永青
503271081 at qq.com
Sun May 24 07:49:30 PDT 2015
---原始邮件---
发件人: "Nicholas Caton"<ncaton at catonenergy.com>
发送时间: 2015年05月24日 21:53:33
收件人: "赵永青"<503271081 at qq.com>;"Julien Marrec"<julien.marrec at gmail.com>;
抄送: "equest-users at lists.onebuilding"<equest-users at lists.onebuilding.org>;
主题: RE: [Equest-users] Reply： The problem of minimum equipment efficiency requirement of Ashrae 90.1-2007
I received some similar review language very recently suggesting 80% efficiency is expected at all/most part load conditions for the baseline boiler….  Similar context in that case with the boiler rarely operating near full load.
 
My comment has other issues that would cloud the topic at-hand, but here is  truncated version:
 
“…Furthermore, the average boiler efficiencies in the Baseline PS-C output reports, calculated by dividing the boiler energy consumption by the annual boiler heating energy generated was… [approximately 5% lower than the nominal efficiency input & documented].  Revise the baseline boiler efficiency to 80% and revise the boiler curve for the Baseline case as necessary to have an average efficiency that is near 80%. Provide updated PS-C reports for the Baseline confirming that the average baseline efficiency is near 80%.”
 
This is the first time I have run into commentary checking up on PS-C’s output at all, and I’m using the same library curves as always for typical baseline boilers.  
 
I believe the PS-C discrepancy is explained both by the non-flat library curve and by the boiler’s default start-up loads, in combination.
 
Here is the default library curve – it is (roughly, but not quite) linear:
 
[For those unfamiliar, the Y-axis is a unitless multiplier]
 
If I’m not mistaken, this curve serves double-duty:  it simultaneously applies the hourly PLR to the full capacity (as either input or auto-sized) and also accounts for increased HIR (lower efficiency) as the PLR drops.  My understanding in equation form:
Energy Consumed (for the hour) = (Boiler full capacity as input/autosized) * (Boiler nominal HIR input @ full load) * HIRf(PLR)
 
If all of that is true, a perfectly “flat efficiency” curve, returning your nominal input HIR at all efficiencies, would therefore be Z = X.  That’s plotted above for reference with a light/thin line. 
 
Even with such a “flat efficiency” curve applied to a test-case, PS-C’s outputs still suggest an annual equivalent HIR higher than the nominal input.  Zeroing out the startup/standby inputs as well is required to get PS-C to report your nominal HIR = annual fuel / annual load:
 
I think the correct response (which perhaps I’ve mostly composed above) is to demonstrate the causes (library curve shape, startup/standby defaults), and to assert these are all appropriately applied to the baseline boiler, though none of this is regulated by 90.1 to the best of my knowledge so it might be relatively shaky territory.  
 
I would wager 90% of all eQuest baseline boilers submitted to GBCI to date probably don’t mess with the library curves or standby/startup inputs, but that’s pure speculation on my part.
 
Has anybody ever tried to explain/justify the default boiler curve and default startup/standby inputs?  Do we know where those defaults come from?
 
~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: Sunday, May 24, 2015 5:34 AM
To: Julien Marrec
Cc: equest-users at lists.onebuilding
Subject: [Equest-users] Reply： The problem of minimum equipment efficiency requirement of Ashrae 90.1-2007
 
Hi,Julien 
 
I understand his meaning is keep a constant efficiency and I know the flat efficiency in equest is a curve that is y=x, but I can't  confirm if a constant efficiency is Ashrae 90.1-2007's original intent.
 
------------------
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 
 
 
 
------------------ 原始邮件 ------------------
发件人: "Julien Marrec";<julien.marrec at gmail.com>;
发送时间: 2015年5月24日(星期天) 晚上8:19
收件人: "赵永青"<503271081 at qq.com>;
抄送: "equest-users at lists.onebuilding"<equest-users at lists.onebuilding.org>;
主题: Re: [Equest-users] The problem of minimum equipment efficiency requirement of Ashrae 90.1-2007
 
Hey,
 
He's saying that you need to make sure that the curve boiler-fPLR gives you a constant efficiency. As far as I remember, the default atmospheric curve from equest is like this.
Don't be confused by "flat". A flat efficiency curve is when you plot efficiency=f(PLR). In equest, it should be a curve that is y=x
 
Look at the curve you used.
 
Best,
Julien
Envoyé de mon iPhone
Le 24 mai 2015 à 11:27, "赵永青" <503271081 at qq.com> a écrit :
I get the energy model comments from LEED reviewer as following:
 
The narrative response indicates that the Baseline boiler has been modeled utilizing operating performance curves and a boiler HIR of 1.25. However, since the boiler operation HIR is based on the performance curves, the HIR is less than 1.25 in the part-load condition, which is inappropriate. Revise the Baseline boilers to include a flat efficiency of 80% for all part-loads. Provide eQuest input files or screen shots verifying the boiler efficiency has been modeled as required.
 <545E22AD at FA528147.9F996155>
However, I can not understand it very much. The minimum equipment efficiency requirement(80 % Et) of Ashrae 90.1-2007 should be base on full load condition.Why the LEED reviewer raise such a question?Any insight is appreciate!!
 
Thanks
------------------
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 
 
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