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Hello Paul,
Based on my understanding the base case for Step 2 is the same as the base
case for Step 1, which would be a gas-fired, 80% efficient hot water boiler
(or two boilers depending on the size of the facility). It seems that the
reason Step 2 exists is to see the incremental benefits and penalties
associated with using a central plant. In your case, you also get to claim
financial benefits or penalties associated with usinig coal as the fuel
source. Distribution losses are always penalties.

Eric Studer, PE

-------Original Message-------
From: Paul Riemer
Subject: [Bldg-rate] District Thermal Energy in LEED
Sent: May 06 '09 01:11

Fellow Modelers,

I would greatly appreciate any answers and comments on formulating a
submission and/or CIR.

I am working on a LEED project which is heated by steam from a coal fired
plant and is subject to the USGBC's District Thermal Energy document [LINK:

Should the baseline hot water boiler plant in the Step 2 analysis be:

A) a coal fired boiler with the proposed boiler efficiency since 90.1 does
not address coal fired boilers,

B) a natural draft coal fired hot water boiler with an assumed code
efficiency since 90.1 does not address coal fired boilers,

C) a natural draft gas fired hot water boiler with the code efficiency
referenced in 90.1, or

D) something else?

Remember the metric is energy cost savings.

If you reread it, replacing the word 'coal' with 'trash', does your answer

Thank you,

Paul Riemer

Eric Studer's picture
Joined: 2011-09-30
Reputation: 200

I would be careful about moving forward with this issue. A CIR might be
the best bet considering your different fuel source. I bet they will
tell you to use oil, which requires a greater baseline efficieny for the

And Eric, in step 1, the baseline heating system is purchased heat which
is usually accomplished with a meter. There is no heating equipment
attached. The purpose of this step is to hold the district energy
system cost neutral to show the actual building cost savings. In step 2,
you model the heating equipment as per Appendix G.

Sam Mason

Sam Mason's picture
Joined: 2011-09-30
Reputation: 0