[BLDG-SIM] LEED / ASHRAE 90.1 Modeling Question

Jason Glazer jglazer at gard.com
Mon Jun 2 09:45:05 PDT 2003


The Standard 90.1 committee has recognized the difference 
between a pass/fail compliance and a savings calculation 
and is in the process of developing informative Appendix G 
"Performance Rating Method" just to cope with these very 
issues. Appendix G is just about to finish up its second 
public review and will be hopefully published within a 
year.  One excerpt from the draft says:

"G3.11 Schedules. Schedules capable of modeling hourly 
variations in occupancy, lighting power, miscellaneous 
equipment power, thermostat set points, and HVAC system 
operation shall be used. The schedules shall be typical of 
the proposed building type as determined by the designer 
and approved by the rating authority. Schedules shall be 
identical for the proposed design and baseline building
design.

"Exception to G3.11: Schedules may be allowed to differ 
between proposed design and baseline building design with 
approval of the rating authority when necessary to model 
nonstandard efficiency measures. Measures that may warrant 
use of different schedules include, but are not limited to, 
lighting controls, natural ventilation, demand control 
ventilation, and measures that reduce service water heating
loads."

I know this does not help today but it will in the future.

Jason

On 2 Jun 2003 at 10:35, Fred Porter wrote:

> Interesting thread. We should keep in mind the difference
> between pass/fail "compliance" using the performance ECB
> method in 90.1 (where only ASHRAE instructions apply), and
> LEED energy savings calculations which use the EMP, CIRs,
> and perhaps DCV as part of our little world of alphabet
> soup. 
> 
> Marcus Sheffer wrote:
>             We will be submitting some shortly and this is
>             how we have interpreted the CIRs. Schedule
>             changes are acceptable is my understanding. The
>             adopting authority in this case is the USGBC and
>             they have stated that schedule changes are
>             allowable for DCV. To be 100% sure, develop your
>             methodology for calculating savings and submit
>             it as a CIR.
> 
>             At 11:47 AM 06/02/2003 -0400, you wrote:
>             Thanks for your reply.
> 
>             I re-read a CIR from 6/7/2001 (perhaps the one
>             to which you are referring?) to be sure that I
>             hadn't missed anything. In the Project Manager's
>             Ruling, it says:"Under the ECM [Exceptional
>             Calculation Method], schedule variations may be
>             used as a basis of engineering calculations for
>             discrete measures that are precluded by the
>             reference standard or the LEEDTM EMP."
> 
>             However, the description of the ECM in section
>             11.5 of the 90.1 manual states that the
>             applicant must provide documentation supporting
>             the accuracy of the exceptional method and that
>             "This documentation must also show that the
>             methods and its results: 1. Do not change the
>             simulation program input parameters that are
>             constrained by the ECM method or any other rules
>             of the adopting authority. For example, the
>             exceptional method may not violate the rule
>             against using different operating schedules for
>             proposed and budget runs."
> 
>             So it is still unclear to me whether or not
>             schedule changes are acceptable. Have you
>             successfully proposed schedule changes such as
>             these through the ECM process? ----- Original
>             Message ----- From: Marcus Sheffer To:
>             wmclaughlin at dmiinc.com Cc: BLDG-SIM at GARD.COM
>             Sent: Monday, June 02, 2003 11:04 AM Subject:
>             Re: [BLDG-SIM] LEED / ASHRAE 90.1 Modeling
>             Question
> 
>             I'd suggest you review the CIRs more closely.
>             DCV has been approved as an energy saving
>             measure and you can modify schedules to simulate
>             savings.You must follow the Exceptional
>             Calculation Method (section 11.5) of the Energy
>             Cost Budget Method of 90.1.
> 
>             At 10:14 AM 06/02/2003 -0400, you wrote: 
>             Hi All,  
> 
>             We are currently working on our first LEED
>             certification project. We use PowerDOE as a
>             modeling tool, but these questions should apply
>             to all modeling platforms. 
> 
>             The LEED process requires modeling practices to
>             follow those outlined in the ASHRAE 90.1
>             Standard User's Manual.The standard does not
>             allow for the augmentation of schedules to model
>             efficiency measures. This is a problem for us in
>             that we often use schedules to simulate measures
>             such as lighting occupancy sensors and demand
>             controlled ventilation. 
> 
>             Typically: 
>             -For lighting occupancy sensors, we adjust our
>             known office schedules using a profile taken
>             from the JIES (I'm afraid I don't have the
>             specific source in front of me). -For demand
>             controlled ventilation, we develop an hourly
>             outside air Fraction of Design schedule for each
>             AHU using known occupancy schedules and an
>             assumption of 20 CFM per occupant. 
> 
>             To us, both of these methods seem to be accepted
>             modeling practice for determining measure
>             performance. However, as stated pretty
>             explicitly in the archived credit interpretation
>             requests (CIRs) on the LEED site, LEED won't
>             allow for the adjustment of schedules to
>             simulate these measures. Does anyone have a
>             method (or insight into developing a method) for
>             either of these calculations in a manner that
>             would be acceptable for the LEED process? 
> 
>             Many thanks in advance for your responses. 
> 
>             Wade 
> 
>             Wade McLaughlin 
>             DMI 
>             450 Lexington St. 
>             Newton, MA 02466 
>             p 617-527-1525 x103 
>             f 617-527-6606
> 
> 
> 
> 
> 
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> 
>             Marcus B. Sheffer energy & 
>             environmental consulting 
>             Energy Opportunities 717-292-2636 
>             1200 E Camping Area Road Fax: 717-292-0585
>             Wellsville, PA USA 17365-9783
>             sheffer at sevengroup.com 
> 
>             a Seven Group member company www.sevengroup.com
>             Marcus B. Sheffer energy & environmental
>             consulting Energy Opportunities 717-292-2636
>             1200 E Camping Area Road Fax: 717-292-0585
>             Wellsville, PA USA 17365-9783
>             sheffer at sevengroup.com a Seven Group member
>             company www.sevengroup.com
> 
> -- 
> Fred W. Porter
> Senior Engineer
> Architectural Energy Corp.
> 2540 Frontier Ave. Suite 201
> Boulder CO 80301
> email: fporter at archenergy.com
> fax: 303-444-4304
> 
> office: 303-444-4149 x225
> mobile: 303-748-4536
> 
> 
> 
> 
> 
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Jason Glazer, P.E.  jglazer AT gard DOT com  847 698 5686
GARD Analytics - http://www.gard.com/
1028 Busse Highway, Park Ridge, IL 60068
Building Energy Simulation and Analysis
Admin of BLDG-SIM list for building simulation users

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