[Equest-users] Chiller COP in baseline building

[Drake.Wahlers at tac.com]

Sam,
In eQuest detailed mode, you can specify a COP at the design condition
you choose. For example, you can enter 5.72 COP (.1748 EIR) @42F CHWT,
85F ECWT, 2.5 gpm/ton under "Design Conditions". Be sure to select that
the chiller is specified at "Design Conditions".  eQuest will then
convert these parameters to a nominal or rated capacity which you can
also specify: 44F CHWT, 85 ECWT, 3gpm/ton, for example.

For simulation, eQuest will adjust the EIR and capacity based upon the
hourly conditions to calculate actual power consumption.

I hope this helps

-Drake

-----Original Message-----
From: equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Sam
Mason
Sent: Thursday, August 13, 2009 11:45 AM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] Chiller COP in baseline building

Everyone,
I am having an issue with determining the baseline chiller COP for a
large lab building. The proposed design system is two 1600 ton
centrifugal machines with 42F CHWT with 12F delta T, 85 ECWT, and
2.5gpm/ton condenser flow rate. Both units are rated at 5.72 COP which
is above the minimum efficiency of 5.60 per Table 6.8.1J.  

In the baseline, there are 4- 800 ton centrifugal machines and per
Appendix G3.1.3.8, the design supply CHWT should be 44F with a 12F delta
T. So the question that arises is: what is the efficiency of the
baseline machines?  If you use standard rating conditions of 44F CHWT,
85 ECWT, and 3.0 gpm/ton condenser flow rate, the minimum COP should be
6.1. If you use the design conditions for the building, it is 5.60.

6.1 versus 5.6 in lab building of >400,000 sq.ft. is a huge difference
and could mean the difference between meeting minimum energy cost
savings for EA credit 1.

Any thoughts, help, or experience is greatly appreciated.

Sam

--
Sam Mason
Atelier Ten
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