WSHP Capacity Greater Than 90.1 Table 6.8.1

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Hi All:
I am looking at a project based on 90.1-2010.? The capacity of the WSHPs are 60 tons.? 90.1-2010 Table 6.8.1B does not list the minimum efficiency of WSHP over 135,000 bBtu/Hr.
Any ideas on how to select the minimum efficiency of a similar system for the baseline?

Thank you,?Paul Diglio
87 Fairmont Avenue
New Haven, CT 06513

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I?d fall back to 6.4.1.1 under the mandatory provisions for the prescriptive compliance path ? that?s the section citing the 6.8 series tables for the purpose of establishing prescriptive compliance. As I?m reading/interpreting, equipment that is not listed categorically within the 6.8-series tables by extension does not need to achieve any minimum performance rating. There is however some complementary text there you?ll want to review carefully to see if anything applies to your situation.

One extra thought: Is it possible you?re dealing with a 60-ton WSHP package, comprised of a combination of smaller heatpumps? In that scenario it may be easier using the individual heatpump capacity ratings to find something that fits the prescriptive mold, so to speak.

~Nick
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Nick Caton, P.E., BEMP
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Regional Energy Engineering Manager
Energy and Sustainability Services
Schneider Electric

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M 785.410.3317
F 913.564.6380
E nicholas.caton at schneider-electric.com

15200 Santa Fe Trail Drive
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Nick:
Thanks for the information.? These WSHP are AAON SA-065-S-C units.? I am waiting for the designer to send me the performance information.

So if there is no efficiency rating for this size unit, should the baseline be modeled with the same efficiency as the proposed model?
Regards,?Paul Diglio
87 Fairmont Avenue
New Haven, CT 06513

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What's the system mapping for the building type and size? The baseline may not even have WSHP, or the mapping should yield a smaller system selection that does apply somewhere in the 6.8 tables.

David

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Hi David:
Yes, for LEED, no problem because it will be a system type 6, VAV with FPB and electric heat.? I was inquiring regarding the utility program here in CT, which requires that the baseline systems be of the same type (WSHP) of the proposed systems using 90.1 minimum equipment efficiencies.

Obviously they will make that decision, I was just curious on what everyone had to say if the baseline system capacity exceeded tables 6.8.1.
Thank you,?Paul Diglio
87 Fairmont Avenue
New Haven, CT 06513

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My opinion is, and past experience verifies, whoever is controlling the money makes the rules. You use whatever HVAC baseline requirement they require. I have the same problem with Washington State Energy Code HVAC requirements and state funding requirements.

Kathryn Kerns
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BCE Engineers, Inc.
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If the baseline could be modeled as modular units, then take the largest one available from the tables. Otherwise I would use equal efficiencies and equivalent capacities (adjusted for the loads) unless there was some additional energy efficiency of the WSHP that you could claim as an exceptional calculation.

The more likely path would be that you can argue that the selection of the large WSHP in innovative in some way for the proposed case and the baseline should be at the 135,000 Btu/hour rate using multiple smaller units since that is what the standard 90.1 provides for. i.e. the baseline system wouldn?t turn out to be one that wasn?t given an efficiency, even if the proposed case fell outside the 6.8 bounds.

David

David S. Eldridge, Jr., P.E., LEED AP BD+C, BEMP, BEAP, HBDP
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Preachin? the truth over here!

I like David?s suggestion to consider your baseline a series of 135,000 Btu/h units matching those prescribed efficiencies. One alternative approach may be to identify and document (in coordination with helpful AAON reps a real-world alternative VE option that would represent how inefficient your designers could realistically specify this ?specialty? equipment under the same design constraints. That would make for an impactful baseline in the context of a utility incentive program.

A little more work, but might yield more a more impressive delta if your incentive program scales with savings.

~Nick

[cid:image001.png at 01D44F63.DDA37260]
Nick Caton, P.E., BEMP
Senior Energy Engineer
Regional Energy Engineering Manager
Energy and Sustainability Services
Schneider Electric

D 913.564.6361
M 785.410.3317
F 913.564.6380
E nicholas.caton at schneider-electric.com

15200 Santa Fe Trail Drive
Suite 204
Lenexa, KS 66219
United States

[cid:image002.png at 01D44F63.DDA37260]

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