Central Chilled Water Plant Serving Building Outside the LEED Boundary Area

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Dear E-quest users,

I'm currently modeling a new construction building served by a central
chilled water plant. The central chilled water plant also serves building
outside the LEED boundary area. The total capacity of the central chilled
water plant is approximately 1370 TR (Two 685 TR Water Cooled Chillers) but
the building i'm modeling within the LEED boundary is just 150 TR.

Is this under DES? But i don't have any idea on what chilled water utility
rate should be used?

Please help me on what modeling strategy should be done on this case?

Thanks in advance.

wallie padero2's picture
Joined: 2011-09-30
Reputation: 0

Hi Wallie,

I believe you can meter the chilled water and attach an "effective" rate to the usage. I assume you have electric chillers? If so, you can take your actual electric utility rates and chiller plant efficiency to get a $/btu of chilled water usage. You should be able to get the total kW/ton efficiency of the plant, I.E. the amount of energy consumed to produce 1 ton of chilled water (chillers, pumps, towers, etc.). Apply your $/kWh to the kW/ton, convert to btu, yielding $/btu of chilled water. This is easier to do with "blended" rates in a spreadsheet and on a monthly basis. Just make sure you match up your billing units on the meter with the units you calculate. A fractional schedule will work for the blended rate in eQuest.

I haven't tried this for a LEED project but I'm not sure what other approach you would use?


Dana Etherington, CEM, LEED AP
email: dana.etherington@crbusa.com
cell: 617-583-3009

Dana Etherington's picture
Joined: 2011-09-30
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Have you read the DES documentation from the USGBC? I believe you
have to follow those protocols.

>> Christopher Jones, P.Eng.

Chris Jones's picture
Joined: 2011-09-30
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