Hi all,
I got a review comment as following:
"It appears that the Baseline Case water side equipment (i.e. Chillers, etc.) was selected/sized based on the project LEED CI peak cooling load only, which appears to be inappropriate. Note that the Baseline Case water side equipment (i.e. Chillers, pumps, etc.) type, size and related controls such as COP, Secondary pump control, etc., must be determined based on the whole-building capacity."
In the reference guide, I only see that we should choose baseline HVAC "type" by base building, but concerning of the baseline equipment aotosizing, I think we should simulate by only our project scope? In my case, the base building is 85 floors and my project only occupies half floor. When I autosize baseline equipment by whole building, the equipement capacity is so large that the loading of chiller is so small, which is not reasonable.
Is there anyone with the same problem? Thanks!!
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5867 thumbs up
May 1, 2020 - 3:11 pm
You select the baseline system from Table G3.1.1A using the whole building area. You then apply a formula from the Reference Guide that creates a weighted average adjustment to the HVAC parameters so that they are sized to your particular project area. The formula varies depending on if the usage patterns in your space are similar or dissimilar to the usage patterns in the rest of the building.
I agree that the review comment is confusing as it implies that you should be using the whole building sizing which does not sound right to me. You can contact the reviewers for a mid-review clarification here - https://www.usgbc.org/contactus
Tzung-Han Ho
Greenjump Sustainability Co., LtdMay 1, 2020 - 10:37 pm
Thanks Marcus.
If I aotosize the HVAC equipment by the whole building and then weighted by the Reference Guide adjustment factors, it's nearly the same meaning as autosize by our particular project area. If I don't use the adjustment factors, the energy saving would be around 90% because the baseline HVAC equipment is oversized too much. That's why I am so comfused.
I'll contact reviewers to clarificate again.
Francesco Passerini
engineer90 thumbs up
January 27, 2021 - 5:48 am
Hello, did you get some clarification about this issue?
If, as the Reference guides states, I select the baseline system from Table G3.1.1A using the whole building area and then I model the project area only, is that correct? Shall I apply a specific formula of the Reference guide? Which one? How can I select Type and Number of Chillers according to TABLE G3.1.3.7 (on the basis of the autosized capacity relative to the project area only?)?
In the proposed building no adjustment shall be made, since the project area has a dedicated HVAC system.
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5867 thumbs up
January 27, 2021 - 2:39 pm
Yes
Yes
It depends on the usage patterns in the rest of the buidling.