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NC-v4 EAp2:Minimum energy performance

DES Systems

Dear LEEDUser friends,

for a project with district systems where Option 1, Path 1 will be implemented how will be the HVAC efficiencies for the proposed model defined? Appendix G, G3.1.1.1,2,3 does not make reference to efficiencies. Could you please assist?

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Marcus Sheffer
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7group / Energy Opportunities
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Thu, 03/16/2023 - 13:18

Model the baseline building plant with conventional equipment as you would do for any other LEED project. Efficiencies come from the appropriate table in Table 6.8.1x.

Thu, 03/16/2023 - 15:24

Hi Marcus, thank you for your response. This is totally understood as far as the baseline model is concerned. However, how will efficiencies for the proposed model be defined in this case?
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Marcus Sheffer
LEED Fellow
7group / Energy Opportunities
LEEDuser Expert
4454 thumbs up

Thu, 03/16/2023 - 15:37

The v4 Reference Guide contains the DES guidance. I tindicates that there are three options relative to the porposed efficiency - monitored data, engineering analysis or default values. So basically you figure out the actual plant efficiency or you use the default values.

Thu, 03/16/2023 - 16:28

Indeed, but since we are going for Option 1, Path 1, there is no specific information about "proposed" efficiencies for this Path? How should we treat this situation?
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Marcus Sheffer
LEED Fellow
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LEEDuser Expert
4454 thumbs up

Thu, 03/16/2023 - 16:50

Under Appendix G the proposed is almost always modeled as designed or as they currently exist. So you figure out the actual efficiencies or use the default values. 
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Marcus Sheffer
LEED Fellow
7group / Energy Opportunities
LEEDuser Expert
4454 thumbs up

Thu, 03/16/2023 - 17:03

There is a formula to use in the Reference Guide.
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Marcus Sheffer
LEED Fellow
7group / Energy Opportunities
LEEDuser Expert
4454 thumbs up

Thu, 03/16/2023 - 17:07

I might be mixing things up. If by Path 1 you are referring to the purchased heating/cooling method then the efficiency of the plant does not matter since you are only accounting for the energy use once it enters the building.

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