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NC-v4.1 EAp2:Minimum Energy Performance

Regd. Path A or Path B water cooled chiller efficiency selection for base case as per ASHRAE 90.1 2013

Anurag Ghosh

Assistant Sustainability Manager

L&T Construction

LEEDuser Basic Member

2 thumbs up

January 31, 2025

We have a hospital project using varable water cooled screw chiller with the minimum COP of 5.9 which is defined as per Path B ASHRAE 90.1 2013

Now as per ASHRAE 90.1 2013, we have to follow Path A for chiller efficiency in basecase where COP comes around 6.11.

So, the proposed case chiller COP(5.9) is less than basecase chiller COP(6.11). Am i making any mistake in selecting the baseline path?

Thanks in advance.

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Tyler Thumma

7Group

LEEDuser Expert

65 thumbs up

Fri, 02/21/2025 - 16:04

This is correct. Make sure the part-load efficiencies are accounted for as well because Path A has better full-load efficiencies but lower part-load efficiencies (IPLV) than Path B.

Jamy Bacchus

Associate Principal

ME Engineers

LEEDuser Premium Member

29 thumbs up

Fri, 02/21/2025 - 16:41

Anurag,
Why are you using 90.1-2013 for v4.1 project?

Anurag Ghosh

Assistant Sustainability Manager

L&T Construction

LEEDuser Basic Member

2 thumbs up

Sat, 02/22/2025 - 13:17

Hi Jamy, The project follows an Indian rating system and expects to follow ASHRAE 90.1 2013. Since this forum also deals with ASHRAE 90.1 related queries, I believed it the right place to ask this question. I apologize for any confusion.

Jamy Bacchus

Associate Principal

ME Engineers

LEEDuser Premium Member

29 thumbs up

Sat, 02/22/2025 - 20:18

Hi Anurag, The LEEDuser forums are grouped by rating system and credit. So if you're using LEED rating system which isn't a USGBC version listed, then you should clarify that in your queries so that we're not crowdsourcing a response which is relevant to a USGBC credit or prereq.

There are a few nuances here: v4 references ASHRAE Standard 90.1-2010 and allows 90.1-2013 to be used in jurisdictions where that's been adopted. LEED v4.1 references 90.1-2016. So your queries on things related to ASHRAE 90.1 and LEED should probably be sorted into those buckets. Here's why that's important: 90.1's Appendix G underwent a complete overhaul in the 2016 version, which changed the methodology for the baseline's creation.

Anurag Ghosh

Assistant Sustainability Manager

L&T Construction

LEEDuser Basic Member

2 thumbs up

Wed, 02/26/2025 - 15:41

Hi Jamy, I completely understand and appreciate you raised this point. I will be careful next time in putting my questions into above buckets. And thanks for the clarification.

Anurag Ghosh

Assistant Sustainability Manager

L&T Construction

LEEDuser Basic Member

2 thumbs up

Sun, 03/02/2025 - 03:43

Hi Tyler and Jamy, Can you suggest whether path A or path B chiller efficiency to be chosen for ASHRAE 90.1 2010 PRM baseline case. It does not specifically mentions about any path unlike path A exclusively mentioned in ASHRAE 90.1 2013/2016? Thanks in advance.

Tyler Thumma

7Group

LEEDuser Expert

65 thumbs up

Mon, 03/03/2025 - 12:50

Path A should be used in ASHRAE 90.1-2010 as well.