[Bldg-sim] fossil hybrid or electric
Arpan Bakshi
abakshi at yrgxyz.com
Wed Aug 29 13:41:46 PDT 2012
It is worth noting there is a difference between LEED Interpretations and
LEED Project Credit Interpretation Rulings, as far as being precedent
setting.
Further Reading:
https://www.usgbc.org/ShowFile.aspx?DocumentID=9277
_________________________________________
*Arpan Bakshi *Sustainability Manager
LEED AP BD+C, ESTIDAMA PQP
*YR&G*
sustainability consulting, education and analysis
*
161 Bowery - 4th Floor - NY NY 10002
*
D 646.704.2880
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On Wed, Aug 29, 2012 at 4:29 PM, Robby Oylear <robbyoylear at gmail.com> wrote:
> Maria,
>
> LEED CIRs are precedent setting under LEED. Any CIR that gets posted to
> the CIR database is considered precedent setting. I agree, the group that
> wrote that CIR was misinterpreting the standard, but without the
> interpretation that Michael just posted we would've had no real way to
> argue against it if it came up as a review comment. Moving forward I would
> proceed as you recommend for Morgan's scenario.
>
> Either way it's unfortunate that the baseline exceptions are limited by
> 20,000 SF of floor area. On a small project you can end up with some very
> awkward fuel switching scenarios between baseline and proposed. I would
> appreciate a 20,000 SF OR X% of the total building area, whichever is
> smaller.
>
> -Robby
>
>
> On Wed, Aug 29, 2012 at 1:20 PM, Maria Karpman <
> maria.karpman at karpmanconsulting.net> wrote:
>
>> Thanks for sharing this Michael! ****
>>
>> ** **
>>
>> Robby, I don’t believe LEED CIRs are precedent-setting. In addition, many
>> Appendix G models are developed for programs other than LEED (e.g.
>> incentive programs) where LEED rulings don’t matter. I would use PTHP on a
>> LEED project for the situation described by Morgan, referencing G3.1.1
>> exception (a), footnote to Table G3.1.1A, and the ASHRAE interpretation
>> that Michael brought up. I don’t think CIR meant to change ASHRAE rules, it
>> just misinterpreted how they apply to this example . For Vinay’s project, I
>> would use PTAC in the baseline since apartments use both gas and
>> electricity as heating source, so fall under Fossil/Electric Hybrid
>> category.****
>>
>> ** **
>>
>> Maria****
>>
>> ** **
>>
>> *From:* Robby Oylear [mailto:robbyoylear at gmail.com]
>> *Sent:* Wednesday, August 29, 2012 3:57 PM
>> *To:* Rosenberg, Michael I
>> *Cc:* maria.karpman at karpmanconsulting.net; Vinay Devanathan;
>> bldg-sim at lists.onebuilding.org
>>
>> *Subject:* Re: [Bldg-sim] fossil hybrid or electric****
>>
>> ** **
>>
>> Interesting. That is obviously the more logical approach, however we now
>> have two conflicting interpretations. The 90.1 interpretation is more
>> recent than the LEED CIR. I'm not sure how one would go about challenging
>> an existing CIR to get it corrected. Does anyone have any experience with
>> this? ****
>>
>> ** **
>>
>> Also, the interpretation does not shed any light on a fossil fuel
>> preheat/DOAS system serving an electric heating system. I would assume
>> that this system would still be classified as Fossil/Electric hybhrid and
>> thus compare to a fossil fuel baseline.****
>>
>> ** **
>>
>> -Robby****
>>
>> On Wed, Aug 29, 2012 at 12:33 PM, Rosenberg, Michael I <
>> michael.rosenberg at pnnl.gov> wrote:****
>>
>> The interpretation issued by the ASHRAE Standard 90.1 Committee agrees
>> with Maria.****
>>
>> ****
>>
>>
>> http://www.ashrae.org/File%20Library/docLib/StdsInterpretations/IC-90-1-2007-11.pdf
>> ****
>>
>> ****
>>
>> *__________________________*****
>>
>> * *****
>>
>> *Michael Rosenberg, CEM, LEED AP *****
>>
>> Senior Research Scientist****
>>
>> ENERGY & ENVIRONMENT DIRECTORATE ****
>>
>> ****
>>
>> Pacific Northwest National Laboratory ****
>>
>> 2032 Todd Street ****
>>
>> Eugene, OR 97405 ****
>>
>> (541) 844-1960 ****
>>
>> michael.rosenberg at pnnl.gov <michael.rosenberg at pnl.gov> ****
>>
>> www.pnnl.gov <http://www.pnl.gov/>****
>>
>> ****
>>
>> ****
>>
>> *From:* bldg-sim-bounces at lists.onebuilding.org [mailto:
>> bldg-sim-bounces at lists.onebuilding.org] *On Behalf Of *Robby Oylear
>> *Sent:* Wednesday, August 29, 2012 12:30 PM
>> *To:* maria.karpman at karpmanconsulting.net; Vinay Devanathan****
>>
>>
>> *Cc:* bldg-sim at lists.onebuilding.org
>> *Subject:* Re: [Bldg-sim] fossil hybrid or electric****
>>
>> ****
>>
>> Maria,****
>>
>> ****
>>
>> I'd have to disagree with you. No where in G3.1.1 exception (a) does it
>> say that you can ignore non-predominant conditions. In fact, if you read
>> the CIR I quoted it very clearly states an example where 90% of the
>> building is electric heat and the other 10% is gas-heat (less than 20,000
>> SF) and the baseline model is determined to be Fossil/Electric Hybrid. *
>> ***
>>
>> ****
>>
>> You may be thinking of the footnote to Table G3.1.1A which states "Where
>> attributes make a building eligible for more than one baseline system type,
>> use the predominant condition to determine the system type for the entire
>> building." However, the CIR is counter to this, and since Table G3.1.1A
>> includes a category for Fossil/Electric Hybrid, your building would only
>> fall into one category.****
>>
>> ****
>>
>> Vinany - the CIR addresses that exact scenario and states that gas
>> furnace-fired DOAS puts you into the Fossil/Electric Hybrid category and
>> your baseline would be System 1 PTAC with HW.****
>>
>> ****
>>
>> -Robby****
>>
>> On Wed, Aug 29, 2012 at 12:13 PM, Vinay Devanathan <
>> vinay.devanathan at gmail.com> wrote:****
>>
>> What would be the case for a project with residences using Heat Pumps for
>> conditioning and a gas furnace-fired DOAS for ventilation to residences and
>> common spaces?****
>>
>> ****
>>
>> Vinay****
>>
>> ****
>>
>> On Wed, Aug 29, 2012 at 3:09 PM, Maria Karpman <
>> maria.karpman at karpmanconsulting.net> wrote:****
>>
>> I think that in Morgan’s case using PTHP baseline is also justified. From
>> what I understand, the project is a residential buildings with electrically
>> heated living units and gas-heated common spaces. Applying G3.1.1 to the
>> project, predominant conditions are residential with electricity as heat
>> source; non-predominant conditions are non-residential with fossil fuel
>> heat. Based on G3.1.1 exception (a), non-predominant conditions accounting
>> for less than 20,000 SF may be ignored when selecting the baseline system
>> from Table G3.1.1A, thus the baseline for the project is PTHP. If
>> residential units were served by WSHP, then predominant conditions would be
>> residential with Fossil/Electric Hybrid heating source, and the baseline
>> system would by PTAC. ****
>>
>> ****
>>
>> Maria****
>>
>> ****
>>
>> *From:* bldg-sim-bounces at lists.onebuilding.org
>> [mailto:bldg-sim-bounces at lists.onebuilding.org] *On Behalf Of *Robby
>> Oylear
>> *Sent:* Wednesday, August 29, 2012 11:14 AM
>> *To:* Morgan Heater
>> *Cc:* bldg-sim at lists.onebuilding.org
>> *Subject:* Re: [Bldg-sim] fossil hybrid or electric****
>>
>> ****
>>
>> Morgan,****
>>
>> ****
>>
>> I agree with Bill. I find this LEED CIR (see below) to be helpful in
>> determining how fossil/electric hybrid systems should be handled. Your
>> scenario sounds similar to item 5 under the examples of systems that would
>> be modeled with fossil fuel heating.****
>>
>> ****
>> LEED Interpretations****
>>
>> 11/1/2011 *ID#10132*****
>>
>> · MPR/Prerequisite/Credit: *EAp2: Minimum Energy Performance*****
>>
>> · Primary Rating System: *Core & Shell v2.0*****
>>
>> Email<https://www.usgbc.org/leedinterpretations/LIDetails.aspx?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>
>> ****
>> Ruling****
>>
>> Clarification is requested regarding when a building heat source in Table
>> G3.1.1A should be identified as "Fossil/Electric Hybrid" versus "Electric".
>>
>> The ASHRAE 90.1-2007 User's Manual states that a fossil/electric hybrid
>> source "refers to a system with any combination of fossil and electric
>> heat, and the baseline system for this is a fossil fuel system". Therefore,
>> the heating source for the proposed building would be considered "Fossil
>> Fuel" or "Fossil/Electric Hybrid" if the building uses any fossil fuel
>> source for space heating (including backup heating or preheating), and the
>> baseline building heat source would be fossil fuel.
>>
>> Exception: ASHRAE 90.1 Section G3.1.1 Exception (a) stipulates additional
>> system type(s) for non-predominant conditions (i.e.
>> residential/non-residential or heating source) if those conditions apply to
>> more than 20,000 square feet of conditioned floor area.
>>
>> EXAMPLES OF BASELINE HEATING SOURCE DETERMINATION:
>>
>> The Baseline heat source from Table G3.1.1A for the following Proposed
>> Case system types would be fossil fuel since the proposed system design
>> includes a combination of fossil and electric heat:
>>
>> 1. Variable air volume system with gas furnace preheat and electric reheat
>> 2. Packaged terminal heat pumps with outside air tempered by fossil fuel
>> furnace
>> 3. Water source heat pumps with fossil fuel boiler
>> 4. Ground source heat pumps with backup fossil fuel boiler
>> 5. 90,000 square feet is conditioned by a variable air volume system with
>> electric reheat, and 10,000 square feet is conditioned with fossil fuel
>> furnaces
>>
>> The following buildings would be modeled with an additional system type
>> with a different Baseline heating source in accordance with Section G3.1.1
>> Exception (a):
>>
>> 1. 90,000 square feet is conditioned by a variable air volume system with
>> electric reheat, and 20,000 square feet is conditioned with Packaged DX
>> systems with fossil fuel furnaces. In this case, the 90,000 square feet of
>> area would be modeled with an electric heat source in the Baseline Case
>> (System Type #6 - Packaged VAV with Electric PFP Boxes), and the 20,000
>> square feet of area would be modeled with a fossil fuel heat source in the
>> Baseline Case (System Type #3 - Packaged Single Zone AC with fossil fuel
>> furnace).
>> 2. 50,000 square feet is conditioned by water source heat pumps with a
>> fossil fuel boiler, and 25,000 square feet is conditioned by electric heat
>> pumps. In this case, the 50,000 square feet of area would be modeled with a
>> fossil fuel heat source in the Baseline Case (System Type #5 - Packaged VAV
>> with hot water reheat), and the 25,000 square feet of area would be modeled
>> with an electric heat source in the Baseline Case (System Type #4 -
>> Packaged Single Zone Heat Pump).
>>
>> Applicable Internationally.****
>> Formal Inquiry****
>>
>> Table G3.1.1A lists two possible categories for the building heating
>> source:
>> (1) Fossil fuel, fossil/electric hybrid, & purchased heat;
>> (2) Electric and other.
>>
>> In cases where the proposed building design includes both a natural gas
>> heating source and an electric heating source, when should the heat source
>> in Table G3.1.1A be identified as "Fossil/Electric Hybrid" versus
>> "Electric"?****
>>
>> Robby Oylear, PE, LEED AP****
>>
>> *Mechanical Engineer*****
>>
>> *Senior Energy Analyst*****
>>
>> * *****
>>
>> *D* 206-788-4571****
>>
>> *www.rushingco.com* <http://www.rushingco.com/>****
>>
>> ****
>>
>> On Tue, Aug 28, 2012 at 5:41 PM, Bishop, Bill <bbishop at pathfinder-ea.com>
>> wrote:****
>>
>> Morgan,****
>>
>> ****
>>
>> My vote is for PTAC with hot-water boiler.****
>>
>> ****
>>
>> Regards,****
>>
>> Bill****
>>
>> ****
>>
>> <wbishop at pathfinder-ea.com>****
>>
>> *From:* bldg-sim-bounces at lists.onebuilding.org [mailto:
>> bldg-sim-bounces at lists.onebuilding.org] *On Behalf Of *Morgan Heater<wbishop at pathfinder-ea.com>
>> ****
>>
>>
>> *Sent:* Tuesday, August 28, 2012 8:12 PM
>> *To:* bldg-sim at lists.onebuilding.org
>> *Subject:* [Bldg-sim] fossil hybrid or electric<wbishop at pathfinder-ea.com>
>> ****
>>
>> <wbishop at pathfinder-ea.com>****
>>
>> Hi – I’ve got an appendix G baseline system question. Here’s the
>> scenario, let me know what you think. <wbishop at pathfinder-ea.com>****
>>
>> <wbishop at pathfinder-ea.com>****
>>
>> Proposed Building: <wbishop at pathfinder-ea.com>****
>>
>> <wbishop at pathfinder-ea.com>****
>>
>> 1. Multi-family residential, amenity/common space < 20,000 square
>> feet <wbishop at pathfinder-ea.com>****
>>
>> 2. Electric baseboard heat in the units <wbishop at pathfinder-ea.com>
>> ****
>>
>> 3. Condensing gas furnaces in the corridors and back of house
>> spaces <wbishop at pathfinder-ea.com>****
>>
>> 4. VRF in amenity common spaces <wbishop at pathfinder-ea.com>****
>>
>> <wbishop at pathfinder-ea.com>****
>>
>> My understanding is that because my non-predominant condition
>> (common/amenity space) is less than 20,000 square feet, I use a single
>> system for the whole baseline building (G3.1.1a). I’ve got a mix of gas
>> and electric heat in the baseline building, does this mean that my base
>> system is PTAC with a hot water boiler? <wbishop at pathfinder-ea.com>****
>>
>> <wbishop at pathfinder-ea.com>****
>>
>> Thanks! <wbishop at pathfinder-ea.com>****
>>
>> <wbishop at pathfinder-ea.com>****
>>
>> <wbishop at pathfinder-ea.com>****
>>
>> Morgan Heater, P.E. <wbishop at pathfinder-ea.com>****
>>
>> BEMP, LEED AP <wbishop at pathfinder-ea.com>****
>>
>> morgan at ecotope.com <wbishop at pathfinder-ea.com>****
>>
>> 206-322-3753 ext 209 <wbishop at pathfinder-ea.com>****
>>
>> <wbishop at pathfinder-ea.com>****
>>
>>
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>> **** <wbishop at pathfinder-ea.com>
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>> <wbishop at pathfinder-ea.com>
>>
>> ** **
>>
>> ****
>>
>> ****
>>
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>> ****
>>
>>
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>> ****
>>
>> ****
>>
>> -- ****
>>
>> Vinay Dev****
>>
>>
>>
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