[Bldg-sim] LEED District Steam Rules: baseline step 1 vs step2

[David S Eldridge]

Agreed, the Table 4 of the USGBC memo shows baseline in Step 2 to be on-site plant or fossil fuel furnace at code efficiencies, per Tables G3.1.1A and 1B.

David
http://www.grummanbutkus.com


From: bldg-sim-bounces at lists.onebuilding.org [mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Sam Mason
Sent: Thursday, December 03, 2009 9:11 AM
To: Ryan Del Balso; bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] LEED District Steam Rules: baseline step 1 vs step2

Ryan,
If you look at Table 4 on page 7of the USGBC District Energy System Modeling Guidelines, you will see district heating for step 2 can be either a heating plant (boilers) or furnaces. Since your building falls under system type 3, I believe you would use Option 1 and model fossil fuel furnaces for heating in step 2.

Anyone else have a thought?

Sam

--
Sam Mason
Atelier Ten

From: bldg-sim-bounces at lists.onebuilding.org [mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Ryan Del Balso
Sent: Wednesday, December 02, 2009 5:41 PM
To: bldg-sim at lists.onebuilding.org
Subject: [Bldg-sim] LEED District Steam Rules: baseline step 1 vs step2

I am working on a LEED energy model for a small <5000sf project that has a hot water loop served by a campus district steam loop.  I am trying to follow the "Required treatment of District Thermal Energy in LEED NC2.2" rules, but am unclear of the requirements it is asking for.  I understand the requirements for the proposed Step 1 and Step 2, but the baseline requirements seem quite unclear to me.

This building falls in the System 3: PSZ-AC with Fossil Fuel Furnace heating type.

My understanding of the requirements are as follows:
- Step 1 baseline: because it is supposed to be cost neutral, I model the systems with a hot water loop and coils served by purchased steam rather than the normal 90.1 System 3- fossil fuel furnace.
-Step 2 Baseline (this is where I am more unclear):
Option 1: model this exactly as described in App G, system 3: with a fossil fuel furnace with 90.1 efficiency (i.e. no hot water loop and coils, and no steam boiler).
Option 2: model this with the hot water loop and coils as in step 1, and put in a hot water boiler with the efficiencies listed in 90.1?
Option 3: model this with the hot water loop and coils as in step 1, and put in a steam boiler with the efficiencies listed in 90.1?


Please let me know if I am understanding step 1 correctly and which option should be followed for step 2.
Thank you for your help.

[cid:image001.jpg at 01CA7407.7854D8E0]


Ryan Del Balso, PE
Building Performance Engineer
ryan at ambient-e.com
130 W. 5th Avenue, Denver, CO 80204
t 303.278.1532x210 | f 303.278.8533 |
ambient-e.com<http://www.ambient-e.com/>







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