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NC-v4 EAp2:Minimum energy performance

Part-load efficiency (IEER)

According to Table 6.8.1B of ASHRAE 90.1.2010 it is required that the baseline HVAC systems serving spaces have a specific full-load and part-load efficiency. However, it is unclear how the part-load efficiency can be entered in the eQuest. Any thought would be appreciated!

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Marcus Sheffer
LEED Fellow
7group / Energy Opportunities
LEEDuser Expert
4454 thumbs up

Thu, 02/05/2015 - 13:45

You will need to check the default performance curves to make sure that they are in alignment with these requirements. eQUEST v6.5 may be up-to-date in this regard, We have not checked yet.

Thu, 02/05/2015 - 14:27

Hi Marcus! Thank you for your reply! We have got a response from the reviewing team according to which “Table 6.8.1B requires that the large baseline HVAC systems serving the spaces have a full-load efficiency of 9.5 EER and a part-load efficiency of 9.6 IEER.” To this we have been asked to provide input reports or screen shots to verify that both the full and part-load efficiencies have been modeled in accordance with Appendix G requirements. However, since the part-load efficiency (9.6 in our case) is not a simple numeric input in the model, how can we verify that the applicable cubic equation (a+bx+cx^2+dx^3) related to the performance curve will still give the desired IEER for the baseline model?
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Marcus Sheffer
LEED Fellow
7group / Energy Opportunities
LEEDuser Expert
4454 thumbs up

Thu, 02/19/2015 - 15:37

There are some good discussions on performance curves in eQUEST on the eQUEST Users Group at onebuilding.org. You should dig into it. In general what the reviewer is asking for is difficult to easily show, as you are finding. It is unusual that they are asking for this information, especially for the baseline system. You will first need to more fully understand the use and creation of default/custom curves in eQUEST. You might want to seek clarification from the reviewer as to specifically what they want to see through a project team inquiry at http://www.usgbc.org/contact Again if you are using eQUEST v6.5 it may have a 90.1-2010 compliance mode. If it does and you are using that version then the reviewer might be satisfied that the IEER is modeled correctly.

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