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Hi John,
Isn't it "simply" a matter of the
derating coil heat transfer and pumping efficiencies, based on the percentage of
glycol concentration? Of course, deriving the derating factors is the not
so simple part... and probably the general solution would be to define a
parametric relationship between the glycol concentration and the coil and
pumping efficiencies.
Glycol manufacturer's data should
have plenty of info on the derating factors, perhaps even a parametric equation
that can be utilized in BDL.
Well that was the easy part... hope
it helps!
Brandon Nichols,
PE Mechanical HARGIS ENGINEERS 600 Stewart St Suite 1000 Seattle, WA 98101 d | 206.436.0400 c | 206.228.8707 o | 206.448.3376 f | 206.448.4450 www.hargis.biz From: bldg-sim@xxxxxxxx [mailto:bldg-sim@xxxxxxxx] On Behalf Of Aulbach, John Sent: Tuesday, January 23, 2007 11:12 AM To: bldg-sim@xxxxxxxx Subject: [bldg-sim] Glycol Chillers/Pacakge units.. Hi Folks:
I am running into a few office/data center buildings where
the main office areas are cooled by conventional chillers and the data
center/server areas are conditioned by either Liebert type package units or 40%
glycol-to-water mix chillers (colder climates that still need servers cooled).
Naturally, both units will be on the same electric meter.
The standard DOE-2 does not model glycol cooling, and
a commercial building does not need the refrigeration version of eQuest.
Usually, I know the kw/ton (or the moral equivalent) of the glycol cooling
source. But glycol/water does not have the same heat absorption properties as
straight shot water to follow the load.
I am trying to insure I am showing the correct energy
used by these units, as I believe the LEED now includes the process loads
within the Base and Proposed models to certify the level of LEED
obtained.
Does anyone have any "tricks" they have
used?
John R. Aulbach, PE, CEM
Project Manager
Nexant,
Inc.
100 North Barranca, Suite
820
West Covina, CA 91791 USA
Phone: 626-430-9054
Fax: 626-430-9060
email: jaulbach@xxxxxxxxxx
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