[BLDG-SIM] [Campus Chilled Water] eQUEST: Central Chiller for Baseline?

[Bill Talbert]

Jon,
 
You indicate your baseline system is System 1 - PTAC. I assume this is
per Table G3.1.1A in Appendix G. If you are simulating building energy
performance per Appendix G (i.e. LEED), then your baseline cooling type
would be Direct Expansion per Table G3.1.1B. Your proposed design
cooling source will be chilled water and you will be comparing it to a
baseline that is using electricity to provide DX cooling. Table G3.1.3.7
referenced in the original email from Yoko only applies if your baseline
system per Appendix G is System 7 or 8, so it is possible to compare a
baseline DX system with a proposed design on a campus chilled water
loop.
 
Table 11.3.2A is only applicable to the Energy Cost Budget approach
used to demonstrate compliance with A90.1. This is not applicable to
LEED unless you are only trying to meet Prerequisite 2 (now largely
irrelevant unless your project was registered before June 26, 2007 and
doesn't have to meet the mandatory EA Credit 1 - 2 points). If however,
this is the path you are on, then you would need to select your baseline
per Figure 11.3.2. System 1 as defined in Chapter 11 is a VAV w/fan
powered boxes. Based on your proposed design system description, it
looks like you would be using System 6 per Chapter 11. 
 
Bill
 
 
 
 
 
 
Bill Talbert, PE, LEED® AP
Mechanical Systems
Phone: (608) 441-6677
E-mail: btalbert at aeieng.com 

Affiliated Engineers Inc.
5802 Research Park Blvd.
Madison, WI. 53719
Tel. (608) 238-2616
Fax. (608) 238-2614

>>> "Jon Evans" <jevans at sustaineng.com> 10/18/2007 4:03 PM >>>

Sam and others,
 
I have a follow-up question related to your response on 9/25 to
purchased chilled water and LEED modeling. 
 
I have a baseline building using ASHRAE 90.1 System 1 (PTAC Units). The
proposed building is using campus chilled water and fan coil units or
water source heat pumps.  Do I use electric as the source for the PTAC
cooling, or the campus chilled water? Using campus chilled water with
PTAC units is not a realistic option, but it seems like 90.1/LEED
requires this (Table 11.3.2A in 90.1-2004)- would USGBC consider this
fuel switching?
 
Also, as a general survey, what are the going rates for campus chilled
water and steam?  I have seen ~$0.70/therm chilled water (generated by
absorption chillers) and $0.35/therm for steam for a college dormitory.
I think these rates will vary by campus and end use.
 
Thanks for your guidance in advance.
 
-Jon 

From:BLDG-SIM at gard.com [mailto:BLDG-SIM at gard.com] On Behalf Of Sam
Mason
Sent: Tuesday, September 25, 2007 8:31 AM
To: BLDG-SIM at gard.com 
Subject: [BLDG-SIM] eQUEST: Central Chiller for Baseline?

 
Yoko,
In note 5 under Table 11.3.2A, 90.1-2004 says for systems using
purchased chilled water, no chillers shall be modeled and CHW costs
shall be determined using the adopting authority’s utility rates.  For
both the baseline and proposed buildings, you would not include central
chillers and instead use purchased chilled water.
 
Sam
 

--
Sam Mason
Atelier Ten
sam.mason at atelierten.com 
 


From:BLDG-SIM at gard.com [mailto:BLDG-SIM at gard.com] On Behalf Of Yoko
Matsuyama
Sent: Monday, September 24, 2007 8:09 PM
To: BLDG-SIM at gard.com 
Subject: [BLDG-SIM] eQUEST: Central Chiller for Baseline?

 

Hi, everyone,

 

I am modeling a building that is served chilled water from a central
chiller, and the building doesn't have any individual chiller. 

I am wondering if  the baseline model (by ASHRAE 90.1-2004) should
follow ASHRAE specified "type and number of chillers" (TABLE G3.1.3.7,
ASHRAE 90.1-2004) depending on building conditioned floor area, or it
should be modeled with a Central chiller as proposed/designed model.  

 

Thank you for your help

 

 

YM 

Graduate Mechanical Engineer
  ==================You received this e-mail because you are subscribed
to the BLDG-SIM at GARD.COM mailing list.  To unsubscribe from this mailing
list send a blank message to BLDG-SIM-UNSUBSCRIBE at GARD.COM
=====================================================You received this
e-mail because you are subscribed to the BLDG-SIM at GARD.COM mailing list.
To unsubscribe from this mailing list send a blank message to
BLDG-SIM-UNSUBSCRIBE at GARD.COM


======================================================
You received this e-mail because you are subscribed 
to the BLDG-SIM at GARD.COM mailing list.  To unsubscribe 
from this mailing list send a blank message to 
BLDG-SIM-UNSUBSCRIBE at GARD.COM
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.onebuilding.org/pipermail/bldg-sim-onebuilding.org/attachments/20071018/254505cf/attachment.htm>