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NC-v4 EAp2:Minimum energy performance

Baseline system in ASHRAE 90.1 G3.1.1

Hello,

I have a question in the process of creating a baseline system in our modelling.
Our project is in System8.

System8 is described in ASHRAE 90.1 G3.1.1 as "each floor shall be modelled with a separate HVAC system...".

In our project, per floor, there are zones that use only electric heat pumps (EHP) and zones that use a combination of electric heat pumps and energy recovery ventilators (EHP+ERV).

In this case, shouldn't we separate the systems even though they are on the same floor?

In addition, it seems that it is correct to separate them for the sake of Table G3.1.2.9 Baseline Fan Motor Power..

 

Thanks!

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Profile picture for user cory.duggin
Cory Duggin
Senior Energy Wizard
TLC Engineering Solutions
LEEDuser Premium Member
44 thumbs up

Wed, 09/13/2023 - 14:53

To determine your baseline system, first go to the basic table and determine the system based on your predominant heating fuel source and residential/non-residential.  Then see what systems or zones should be modified based on the exceptions.  If your secondary system type met an exception such as serving more than 20k sf for a different heating source or residential/non-residential, then you could need a different baseline system in addition to your system 8's.  The ERV on the other systems will just act as an ECM for those systems.  The system 8's per floor will just have to handle all the OA conditioning without any help from an ERV unless the OA fraction is over the limit to require and ERV in the baseline.

Wed, 09/13/2023 - 23:30

Thank you for reply Duggin, However I've a one more question
If our project doesn't allocate exceptions, can we addition A(section 6.5.3.1.1) value the baseline system fan power? We consider A value in baseline sytesm Table 6.5.1.1.1B.

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