[BLDG-SIM] RE: Process Loads and LEED

[gail]

The modeling approach you suggest for process loads would not comply with
the current requirements for LEED.  The 25% process load requirement is set
up as a minimum process load requirement to avoid underreporting of process
load energy usage (i.e. an office building reporting 0.25 W/sf of
miscellaneous equipment).  However, all projects are still expected to
follow the Appendix G, Table G.3.1.12 requirements for receptacles and
process loads, stating that "these loads shall be included when calculating
the baseline building performance and proposed building performance").
Unless LEED requirements change, If your building is expected to consume 60%
process energy, it should be modeled with 60% process energy, and the
Percentage Improvement should be calculated with your projected actual
process energy consumption included in the energy results.  I would echo
Marcus' recommendation unless & until the EA TAG comes up with an alternate
solution:

"In the mean time I would suggest that project teams strive to make all
building energy systems as energy efficient as possible and follow the
exceptional calculation method to show savings for process loads in the LEED
certification review process."

 Best Regards,

Gail Stranske
 On 3/6/07, Varkie Thomas < thomasv at iit.edu> wrote:
>
> Thanks for all the responses.  It does not solve my problem where the
> proposed process load in this "office" building that I am looking at is more
> than 60% of the total annual energy use.  Here is a suggested solution.  The
> proposed process load should be entered in the baseline and proposed models
> since it affects the heating and cooling loads and the difference in
> efficiencies of the baseline and proposed systems serving the
> loads. However, when determining the percent energy savings for LEED
> certification, the common process load should be removed from both sides.
>
> I apologize for bothering BLDG-SIM subscribers with more questions because
> of my ignorance.
>
> A high process load offsets the heating load in the perimeter zones and
> you can get a building in a cold climate with no heating.  If the perimeter
> zone is reduced to 1 foot with no process loads, people or lighting, then
> the computer program will not account for the benefit of day-lighting on the
> lighting system unless the program can ignore this perimeter zone and apply
> day-lighting to the adjacent zone if it is separated by an "AIR-WALL" (
> DOE2.1E).
>
> The building that I am looking at has ceiling PIU boxes designed to
> serve a less than 1 foot perimeter zone and UFAD PIU boxes serving the
> interior zone.  Both sets of PIU boxes are served by the same system.  In
> this building, the glass height is 12 feet and the ceiling height, beyond
> the 1 foot perimeter zone, is 10 feet.  Since the zone depth entered into
> the program is 15 feet and has a 10 foot ceiling, eQUEST flags it down as an
> error but not DOE2.1E.  Perhaps VisualDOE will not call this an error.
>
> How would you turn off the Airside Economizer in a DOE2 based program.
> With TRACE700 you can say Yes or No.  Climate zone 3A does not require and
> airside economizer for the baseline for a large office building.  Setting
> the "Drybulb High Limit" and the "Economizer Low Limit" in eQUEST to their
> maximum values of 80F seems to do the trick.  I cannot find the Waterside
> Economizer in eQUEST although the keywords and commands for modeling
> this, exists in both DOE2.1E and DOE2.2.
>
> How is the Zone-Fan-Ratio (ZFR) determined for Fan Powered Terminal
> Boxes?  In eQUEST the default for Series FPB is 1.0 and for Parallel it is
> 0.5.  How was this determined.  The definition in the DOE2.2 manual is:  ZFR
> * Primary CFM = FPB Supply CFM.
>
> In the case of the project I am looking at (a UFAD system with Parallel
> FPBs) the Primary Air Temp is 48F (for dehumidification), the FPB Supply Air
> Temp = 65F and Recirculation Air Temp is 78F.  What is the ZFR?  Would
> an increase in ZFR reduce the energy use.   The Simulation Guidebook by
> Energy Design Resources suggests putting 25% of the people and 33% of lights
> and equipment in the ceiling plenum.  This produced very little in energy
> savings.
>
> Is this an acceptable solution:
> Summer Cooling Indoor Temp:  From 0' to 7' at 75 F.  From 7' to 10' at 85
> F   Average Temp = 78 F.   (0.7*75) + (0.3*85) = 78
>
> Winter Heating Indoor Temp:  From 0' to 7' at 72 F.  From 7' to 10' at 62
> F   Average Temp = 69 F.  (0.7*72 ) + (0.3*62) = 69
>
> (As with the theoretical method of moving internal loads to the plenum,
> the fact that hot air collects at the top should be not an issue since we
> are looking at heating only the mass of air from 0' to 7' to 72 F).
>
> How would you account for the energy savings using ECM motors.  One
> suggestion is to reduce the energy use of the fans in PIU boxes by 25%.  The
> default KW/CFM in eQUEST is 0.00033 (0.33 kw for a 1000 cfm box).
> Reducing this by 25%  produced almost no energy savings using eQUEST.
>
> According to the Code of  Federal Regulations (10CFR435/436) occupancy
> based lighting sensors can be modeled by reducing the lighting
> schedule/profile fraction by 30%.  Is this acceptable to LEED?   I am
> assuming that occupancy based ventilation can be modeled by creating a
> MIN-AIR-SCH (DOE2.1E) that is equal to the design OA fraction (from a
> trial run) multiplied by the occupancy schedule fraction.
>
> The energy program developers should provide guidelines for modeling
> energy conservation measures using their programs.  Code and LEED
> authorities should test them and approve them.
>
>
> ----- Original Message -----
> From: Mike Tillou <miket at etcgrp.com>
> Date: Tuesday, March 6, 2007 4:21 pm
> Subject: RE: [BLDG-SIM] Process Loads and LEED
> To: thomasv at iit.edu , BLDG-SIM at gard.com
>
>  I went back and looked at the public review version of LEED 2.2 dated
> December 2004 on the cover and October 19 in the footer.  Here is how the
> original credit was proposed:
>
> *"Must be compared against a baseline building that both complies with
> Appendix G to Standard 90.1-2004 (without amendments) and that has a
> process energy consumption that is a minimum of 25% of the total energy
> consumption for the baseline building."*
>
> In the final version of the the LEED 2.2 dated October 2005 that same
> verbiage had been changed to
>
> *"Must be compared against a baseline building that complies with Appendix
> G to Standard 90.1-2004 (without amendments). The default process energy
> cost is 25% of the total energy "*
>
>  I think the intent is that the default process energy cost used in the
> calculation of LEED credits for V2.2 is a max of 25%.  *If your building
> has 60% process energy you would only have to count that portion of process
> energy that equals 25% of the total energy. *  This would level the
> playing field for all buildings regardless of how much process energy is
> used.  If a building uses less than 25% then you have to justify the
> legitimacy of that claim.
>
> I think someone should submit a CIR asking whether this is the correct
> interpretation of the Credit.
>
> Respectfully,
>
> Mike
>
> Michael Tillou, PE
> ETC Group - Energy Engineering for a Sustainable Future
> Ph:413-458-9870
>
>


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