[Bldg-sim] A Question about chilled water usage

[James V Dirkes II, PE]

Dear Vikram,

I think that the definition of ton-hours is inherently an "cooling energy
delivered" or "useful energy", metric.

 

The Building Performance Team
James V. Dirkes II, P.E., LEED AP
1631 Acacia Drive NW
Grand Rapids, MI 49504
616 450 8653

 

From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Sami, Vikram
Sent: Friday, September 10, 2010 4:23 PM
To: bldg-sim at lists.onebuilding.org
Subject: [Bldg-sim] A Question about chilled water usage

 

I'm looking at utility data for a building on a college campus that has a
central utility plant. They list cooling energy in ton-hrs and It seems
really high for all buildings across the board. 

 

However - if you assume that ton-hrs is the metered chilled water usage and
not the chiller energy, its not that bad. For example if the chilled water
usage is 1 ton-hrs, that's 12,000 BTU's of cooling energy delivered.
However, if whats being measured is chilled water usage (and not chiller
energy), then 1 ton-hr is not the energy consumed by the chiller - that
should be 12,000BTU/COP of the chiller. So if the chiller COP is 4 - then
that's only 3,000 BTU's of energy consumed to deliver that ton-hr.

 

So - to get to the point - does anyone know if campuses monitor their
chilled water usage (in ton-hrs) as chiller energy or cooling delivered?

 

(I hope this makes snese)

 

Vikram Sami, LEED AP

Sustainable Design Analyst

1382 Peachtree St. NE, Atlanta, GA 30309

t: 404-443-7462    f: 404.892.5823       e: vikram.sami at perkinswill.com
<http://www.perkinswill.com/> www.perkinswill.com

Perkins+Will.  Ideas + buildings that honor the broader goals of society

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