LEED CI V4 Tenant space modeling interpretation

1. Yes

2. Yes that is what is required due to the exception in the prerequisite language. Personally I don't agree with the exception in LEED. Makes no sense to me to model something that does not exist in the Proposed model. This is a less accurate way to model and contradicts the intent of Appendix G to model the proposed case as designed. It is also a contradiction to the next set of sentences in the prerequisite language encouraging teams to accurately model plug loads.

3. The proposed central plant should be modeled with the efficiency of the designed/installed equipment. The baseline system uses the 90.1 minimally compliant efficiency. Sizing the system to the space uses method 1 or 2 as you describe.

In what relates with bullet 2:

1) ASHRAE 90.1 App. G Table G3.1 (5) section f states that when evaluating energy performance in existing buildings, baseline building envelope shall be considered equal to proposed building envelope (so, equal to proposed envelope), prior to any revision;

2) LEED Reference Guide, has an exception that do not allows the use of this section f from App. G. Thus, Baseline building envelope must be modeled per ASHRAE 90.1 (Tables 5-5-1 through 5-5-8) and not equal to proposed building envelope (that shall be modeled as-is). 

Can you please confirm that I'm understanding this correctly? Because this is a bit different from what you have said before an has impact in results.

Regards,

Yes you understand correctly.

Keep in mind this only applied to commercial interiors projects and does not apply to BD+C projects. The exception is in the prerequisite language for CI and not there for BD+C. If I stated otherwise please let me know where I did so and I will go correct it.

Thank you Marcus.

When reading bullet 2 of the original post (transcripted below), I think it means to consider the same envelope in both buildings (baseline and proposed) and with thermal performance as defined in ASHRAE 90.1 (no matter what type of envelope real building has).

"2. The project scope of work exclude renovations of windows or exterior walls. The envelope components would be same in baseline and proposed case model and as per ASHRAE 90.1-2010 appendix G baseline envelope requirements. Moreover,The base building was built in 2007."

Thanks for catching that. What I said was not correct. The Baseline is the code minimum and the Proposed is as installed. I still disagree with the application of the exception to the baseline. Unfortunately it does not appear that I can go back and edit my previous comment so I hope folks read them all!