See all forum discussions about CI-v4 EAc2
 Subscribe to new posts about CI-v4 EAc2 Post a new question aboutCI-v4 EAc2
See LEEDuser’s guidance on CI-v4 EAc2»
FAQs about EAc2 :

The energy cost offset from onsite renewable energy cannot be used to demonstrate compliance with the prerequisite. Can this cost offset still be credited to the proposed energy cost savings for this credit?

View answers »

Forum discussion

CI-v4 EAc2:Optimize energy performance

Energy Modelling - Baseline water-cooled chiller's COP, adjusted to local outdoor conditions in lieu of AHRI conditions?

Dear LEED APs,

I have a LEED CI v4 project in Taipei, Taiwan, which require whole building energy modelling. Couple of questions I hope to seek clarity:

 

Question 1:

The project has peak cooling load larger than 2110 kW, and noted that water-cooled centrifugal chillers, no greater than 2813 kW, are all required to be sized equally. However, do we need to use COP 6.1 for the baseline chillers (at AHRI conditions)? Or can the COP be adjusted to project's outdoor conditions? For example, under AHRI rating conditions, COP 6.1 is derived with condenser water temperature leaving cooling tower at 30 degC. But in the case of Taipei's outdoor condition, the designed condenser water temperature leaving cooling tower is 31.35 degC based on methodology detailed under G3.1.3.11. Surely, with a higher condenser water temperature leaving cooling tower, this will have a detrimental effect on the chiller's performance and corresponding COP. Will USGBCI allow project to adjust the chiller's COP in the baseline model such that both baseline model and proposed model will be simulated under project's outdoor conditions?

 

Question 2:

Under what circumstances can the project pursue 6.4.1.2: Minimum Equipment efficiencies (listed equipment) - nonstandard conditions?

 

Thank you!

 

Rgds,

Andrew Xiao

0
Post a reply

You rely on LEEDuser. Can we rely on you?

LEEDuser is supported by our premium members, not by advertisers.

Go premium for $15.95  »

Profile picture for user sheffer
Marcus Sheffer
LEED Fellow
7group / Energy Opportunities
LEEDuser Expert
4454 thumbs up

Mon, 03/18/2019 - 19:46

1. You must use the efficiency at the rated conditions. The software should account for the outdoor conditions that would impact these systems in the weather file. It sounds like you are falling into the trap of trying to design the baseline system. 2. This just applies to the proposed systems operating under non-standard conditions when complying with this mandatory provision. 

Add new comment

To post a comment, you need to register for a LEEDuser Basic membership (free) or login to your existing profile.