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

[Carol Gardner]

This may make the SS-F report the most useful one.
Carol

May Xu wrote:
> 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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