Required Treatment of District Thermal Energy in LEED-NC version 2.2

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Recommended summer reading:

Paul Riemer's picture
Joined: 2011-09-30
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SIM List,

Does anyone have an opinion on whether this document
will help to allow a direct comparison between installing a geothermal
plant rather than connecting to an existing steam plant in a campus
situation (University).`

As I've read it so far this type of comparison is what the document is
intended to address, however upon closer reading the actual energy study
requirements for Step 2 (Aggregate building / DES scenario) energy model
the comparison requires a "virtual on-site hot water / chiller" for the
proposed case model rather than comparing the central plant in the
baseline model to an "as designed" model such as is the case in Step 1.

Any thoughts on this discrepancy?

Eric Youngson

Eric Youngson's picture
Joined: 2011-09-30
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I believe this document as written applies only if the project utilizes district energy and so if you are not using district energy, Tables G3.1.1A & B stand.

According to the document, feedback should go to leedinfo at and I have just submitted the following questions:
Does Table 4 direct the comparison of all district energy cooling against electric cooling?
Does Table 4 direct the comparison of all district energy heating against natural gas or oil fired heating?

Is the intent to model the district energy system with the utility rates that it actually operates under?

Are the project's saving adjusted lower if the proposed or default district energy system efficiency is lower than the baseline system efficiency?

Worded another way:
Does the project receive Step 2's point value whether it is higher or lower than Step 1 within the bounds of
1) maximum of 4 additional points by Step 2 over Step 1
2) 2 points shown in Step 1 (because if Step 1 shows 2 or more points and Step 2 shows less than 2 points, then the project would elect not to pursue more than the minimum and thus not document Step 2)

I encourage others to share their questions or feedback while the document is new. Also, ASHRAE's 90.1 ECB committee is working on addressing the same issue which presumably will result in a publicly reviewable proposed addenda.

Paul Riemer

Paul Riemer's picture
Joined: 2011-09-30
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Dear All,
I am looking for the weather data of San Ramon, CA or Escondido, CA, any
help is appreciated.

Sun, Jian's picture
Joined: 2011-10-02
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I've put the beta version up on the website (beta website - still needs
a lot of work).

In the next couple of weeks I should have the weather file downloads
available for it (and the tutorials over the next couple of months once
I get my TA for the fall semester assigned to me). In the meantime, its
got Chapel hill weather.

The website is:

Its a work in progress - I'd love input/comments/curses/abuse - its all

Vikram Sami, LEED AP

Vikram Sami's picture
Joined: 2011-09-30
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Eric, for LEED, your case of a proposed geothermal design against an appendix G baseline wouldn't have to involve the district energy since the baseline only has district energy if the proposed design also does.

A comparison of geothermal to district energy would be on your own terms to decide which system to recommend as far as client economics. For LEED, you would use the new 2-Step system for your points, which would use a different baseline than in the geothermal case.

Paul, I agree with your interpretation about earning two points in Step 1 compared to earning one or no points under step 2 when considering district energy plant efficiencies.

In effect, this document gives you the opportunity to certify your project by doing the best you can with an existing district energy plant where you might otherwise be excluded from LEED certification if you were forced to include it. At the same time, allowing those who have more efficient district energy systems to take credit.


David S Eldridge's picture
Joined: 2011-09-30
Reputation: 2000

Are you looking for typical year or actual year weather data for these sites? The closest locations in the new TMY3 data set are Carlsbad/Palomar for Escondido, and Concord Buchanan Field for San Ramon.

I have just packed the TMY3 weather set into DOE-2 *.bin format, and am looking into a way to put them on the Web for download.
In the meanwhile, attached are the files for Carlsbad and Concord (sent to Jian Sun only).

Joe Huang

Joe Huang3's picture
Joined: 2011-10-02
Reputation: 0

Thanks you, Joe, the files you sent is what I am looking for, thanks!


Sun, Jian's picture
Joined: 2011-10-02
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Hello All:

A Non-eQuest question..

Can anyone give me a good number for the cost of generating chilled
water from a central plant (to sell to a Customer)? This CHW will be
generated by an absorption chiller which gets its input from a
cogeneration system (probably gas fired reciprocating engine).

I think the number I need is the "cost to generate" side. I will let the
Client decide his profit margin.

A friend inquired to me, and I know there is VAST experience from the
fine people on this Web Site.

My thanks.

John R. Aulbach, PE, CEM

Aulbach, John's picture
Joined: 2011-09-30
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