[Bldg-sim] Spam:Re: LEED NC Submittal Template, Heating/Cooling Hours Loads Not Met

[May Xu]

The definition of "unmet load hours" in Edition 3 of LEED-NC 2.2 (page
187) is "occupied periods where any zone is outside its temperature
setpoint". I noticed the words "occupied period". Does it mean the unmet
hours in "non-occupied periods" (e.g. at mid-night when no people in the
building) can be excluded? If I am right, the % in BEPS report counts
both occupied period and non-occupied period.

May

-----Original Message-----
From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Carol
Gardner
Sent: Friday, August 22, 2008 2:44 PM
To: Michael Tillou
Cc: bldg-sim at lists.onebuilding.org; 'Brandon Nichols'
Subject: Re: [Bldg-sim] Spam:Re: LEED NC Submittal Template,
Heating/Cooling Hours Loads Not Met

I have always looked at the SS-F report. Does any one else use it?


Michael Tillou wrote:
> If you're using eQuest the Air Side Summary report in the eQuest
interface
> has all that info.  It is also reported in SS-R Zone Performance
Summary in
> the .SIM file.     
>
> -----Original Message-----
> From: bldg-sim-bounces at lists.onebuilding.org
> [mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Jay
Keazer
> Sent: Thursday, August 21, 2008 5:16 PM
> To: Dan Russell; Brandon Nichols; bldg-sim at lists.onebuilding.org
> Subject: Re: [Bldg-sim] Spam:Re: LEED NC Submittal
Template,Heating/Cooling
> Hours Loads Not Met
>
> I am not certain, but I think the unmet load hours on the BEPS report
is
> consistent with the definition in Addendum a.  The BEPS report says
"Percent
> of hours any system zone outside of throttling range."  To me this is
the
> same as "one or more zones" being out of range for a particular hour.

>
> Adding up the unmet load hours of every zone would count a lot of
coincident
> unmet hours and could get large with a lot of systems (note this is
what
> SS-R does for multiple zone systems).  It could be greater than 8760,
and I
> don't think this is what appendix G is looking for.  If a lot of zones
are
> out of range during an hour (say an exceptionally cold night) that
should
> only count as 1 hour.
>
> I don't think that the number on the BEPS is for the "worst case
zone."  I
> just checked a SIM file I had open and the BEPS report listed 3.3%
unmet
> load hours, so 289 hours (actually anywhere from 285-293).  Looking
through
> SS-R for each zone, the worst case had 177 hours under heated + 24
hours
> under cooled, so 201 total unmet hours.
>
> I have always gone by the BEPS (i.e. 3.4% or less is good), but have
never
> known how to find more detailed output regarding how many are cooling
vs.
> how many are heating.  Theoretically I think you could do this with an
> hourly report for every zone and some postprocessing, but I don't
really
> want to go there.  Anybody have a more practical approach?
>
>
> Jay Keazer,  EI
> Energy Engineer
> TME, Inc.
> 2039 N Green Acres Road
> Fayetteville, AR  72703
>  
> ph   479.521.8634
> fax  479.521.1014
> jkeazer at tmecorp.com
> www.tmecorp.com
>
>
>
> -----Original Message-----
> From: bldg-sim-bounces at lists.onebuilding.org
> [mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Dan
Russell
> Sent: Thursday, August 21, 2008 1:12 PM
> To: Brandon Nichols; bldg-sim at lists.onebuilding.org
> Subject: Spam:Re: [Bldg-sim] LEED NC Submittal
Template,Heating/Cooling
> Hours Loads Not Met
>
> Brandon, I have been on the same page regarding this issue, and have
> submitted for successful LEED certifications using those assumptions
..
> until I read Addendum a to 90.1-2004, which adds the definition of
"unmet
> load hour" to Section 3.2.  The definition is:
>
> unmet load hour: an hour in which one or more zones is outside of the
> thermostat setpoint range.
>
> Unfortunately this seems to clearly indicate the unmet load hour value
asked
> for refers to all zones at once.  
>
> My previous assumptions to only consider the worst-case zone were
based on
> the example set forth by the USGBC's document titled "Example LEED-NC
> v2.1 Energy & Atmosphere Credit 1 Submittal", which I referenced back
when I
> did my first LEED submittal in 2005.  This document is still available
from
> their server at the following address:
>
> http://www.usgbc.org/ShowFile.aspx?DocumentID=2423
>
> This document uses the following paragraph to demonstrate compliance
with
> the unmet load hour requirement:
>
> "The worst-case zone in the budget case is a North classroom. This
zone is
> under-heated 40 hours out of the year in the Energy Cost Budget case
and 0
> hours per year in the Design Energy Cost case. This is within the 50
hour
> per year limit required by ASHRAE 90.1-1999."
>
> Now, if Addendum a were not used in any part as basis for LEED
submittal one
> could possibly argue using the quoted precedent above.  Granted, the
above
> precedent applied to the 1999 version of 90.1 and the 2.1 version of
LEED,
> but it seems to reasonable that the implications made there should
carry
> over until otherwise directed (as in Addendum a).
> Furthermore, it is my opinion that 90.1-2004 (not including addendums)
does
> not clearly resolve the issue.  The ASHRAE technical committee must
have
> agreed, hence the inclusion of the new definition for "unmet load
hour" in
> Addendum a.
>
> So, if Addendum a is not used, there may be a possibility to consider
unmet
> load hour only on a worst-zone basis.  However, if Addendum a is used
it
> seems clear that the unmet load hour applies to all zones at once.
>
> Certainly larger project simulations with multiple zones will suffer
from
> this added definition.
>
> Thanks,
>
>  Dan Russell, EIT 
>
>
>
>
> -----Original Message-----
> From: bldg-sim-bounces at lists.onebuilding.org
> [mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Brandon
Nichols
> Sent: Thursday, August 21, 2008 11:22 AM
> To: bldg-sim at lists.onebuilding.org
> Subject: [Bldg-sim] LEED NC Submittal Template,Heating/Cooling Hours
Loads
> Not Met
>
>  
> All,
>
> "Table 1.3 -- Advisory Messages" of the LEED NC Submittal Template
requests
> "number of hours heating loads not met" and "number of hours cooling
loads
> not met".  We've taken a vote here in the office, and its 2-0 in favor
of
> reporting the worst case zone as shown on the BEPS report.
>
> But we have some lingering doubts... can anyone say definitively what
> numbers are being asked to for here?  our runner-up in the voting was
the
> total of all zone hours out of throttling range -- however this could
easily
> exceed the limit of 300 hours on a large project with many zones.  
>
> As 300 hours is less than 5% (3.4% actually) of 8760, we think that
the 300
> hours is "per zone", not a total limit for the entire project.  
>
> Comments appreciated....
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