- Our development is having 767.47 sqm of supporting offices and 21,340.69 sqm of data center related area. Based on the COMNET Commercial Buildings Energy Modelling Guidelines and Procedures dated 22 December 2014 at page 165, it is stipulated at section 7.1.3 Data Centers – Data Center HVAC Systems that “Either System 3 (PSZ-AC) or system 4 (PSZ-HP) shall serve the data center”. By this definition, hence our baseline HVAC systems for data centers are will be using system 4. Is our understanding correct?
- We notice there is another alternative compliance path for LEED for Core and Shell projects which revised the point thresholds for EAp2 and EAc1 based on the owner-influenced energy percentage (http://www.usgbc.org/resources/cs-2009-eap2-c1-acp). It is anticipated that tenant-influenced energy at our development will be at the range of 70%, which mostly is from their IT load. Hence if we are using the revised point thresholds for EAp2 and EAc2. The scale points will be as following – Prereq at 4%; 3 pts at 6.4%; 4 pts at 7.2%; 5 pts at 8% and so on. Is our methodology is correct?
You rely on LEEDuser. Can we rely on you?
LEEDuser is supported by our premium members, not by advertisers.
Go premium for
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5867 thumbs up
November 15, 2017 - 12:36 pm
1. You are not supposed to use COMNET to determine the baseline system. You need to use 90.1 Appendix G.
2. You can apply that methodology.
Michael Wahjudi
Sustainable Consultant3 thumbs up
November 15, 2017 - 8:31 pm
Hi Marcus. Thanks for the feedback.
1. May I know why we can't use COMNET to determine baseline system? Since USGBC website is indicating COMNET as one of the resources for modelling guidelines. At the COMNET website, it is indicated as well that this guide can be used to determine baseline and earn LEED credits.
2. The clause on ASHRAE 90.1 - G3.1.1 exception B indicates "Examples where this exception may be applicable include, but are not limited to, computer server rooms,...". Based on this statement, we can use system 3 or 4 for computer server rooms. Am I right?
3. If we can't use system 3 or 4 for computer server rooms. How to determine which of the spaces that eligible for system 3 or 4 from the ASHRAE 90.1 - G3.1.1 exception B?
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5867 thumbs up
November 16, 2017 - 9:37 am
1. If it aligns perfectly with 90.1 Appendix G you can certainly use it. COMNET can be a good resource for certainly modeling methodologies, plug load values, etc. You can cite parts of it as justification for how you modeled something. It is not a substitute for Appednix G.
2. I don't think you are applying the requirements of Table G3.1.1A correctly. In your case the predominant condition is the data center. So G3.1.1 exception b would apply to the office. A data center is not a computer server room.
3. Enter Table G3.1.1A with the heating fuel type and area/floors of the building. If you have no heating you use electric. Based on the area you provided this would be a system 7/8. See the note in the bottom of the table that indicates predominat condition which has been interpreted to be by area for virtually all project types. Then based on the difference in schedule you could probably model a system 3/4 for the office. Exception b does not apply to particular space types. The examples given may apply in certain situations. So you select the baseline system based on the predominant conditon and then you start to apply exceptions to it under G3.1.1.