[Bldg-sim] Baseline Modeling for LEED

[David S Eldridge]

Quick answer:

90.1 does not care if you are pursuing EQC2, use the same OA quantities in baseline and proposed for EAC1.


Long answer:

These are separate credits - the modeling takes place based on the proposed design in comparison to a baseline that is only restricted by 90.1.  The OA requirement should be the same in both models subject to any DCV or exceptional calcs or technologies.  This is not affected by other LEED credits.

The credit for increased ventilation takes place "before" modeling starts.  This is besides the many cases for laboratories or hospitals where the local code ventilation requirements are much greater than ASHRAE 62.1 already - the proposed design is in effect already taking the EAC1 penalty but earning the credit for increased ventilation under the best practice design.  You wouldn't relax the baseline ventilation to less than 30% in these cases!

I'm sure there are some proposed buildings out there that condition OA very effectively, and may gain EAC1 gross energy cost savings by having increased ventilation, but even where that effect occurs there is  the question of percentage savings applying to a larger energy consumption and cost.

Overall if you gain EAC1 points by pursuing increased ventilation, I think you have worked well within the system - good for you in designing a system to condition outside air so effectively.  For many projects (other than labs or hospitals which may have to use that quantity of OA anyway) I would expect EQC2 could be trading for an EAC1 credit, so you'll have to prioritize.  Both are rewarded from USGBC, but EAC1 is also rewarded in lower utility bills.

David
http://www.grummanbutkus.com



From: bldg-sim-bounces at lists.onebuilding.org [mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Vikram Sami
Sent: Thursday, November 19, 2009 4:20 PM
To: Nathan Miller; Rimes, Christie; Steven Rutter; bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] Baseline Modeling for LEED

I always assumed that if you went to 30% extra, you kept the baseline at 100%, and the designed building at 130%, but after reading this, it does seem to make sense that you would increase both occurrences.

Can anyone from the EA Tag chime in?

Vikram Sami, LEED AP
Direct Phone 404-253-1466 | Direct Fax 404-253-1366
LORD, AECK & SARGENT ARCHITECTURE

From: bldg-sim-bounces at lists.onebuilding.org [mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Nathan Miller
Sent: Thursday, November 19, 2009 4:42 PM
To: 'Rimes, Christie'; 'Steven Rutter'; bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] Baseline Modeling for LEED

I disagree, I believe the models should be same-same on ventilation rates. See section 90.1 (2004) Section G3.1.2.5. It states:

"Minimum outdoor air ventilation rates should be the same for the proposed and baseline building designs."

In my projects (including those that include 30% additional outside air), I have always used the same outdoor air flow rates, unless I was taking credit for demand control ventilation in the proposed case (see the exception allowed in that same ASHRAE section).

Nathan Miller
Senior Energy Engineer/Mechanical Engineer
direct: 206.788.4577
fax: 206.285.7111

From: bldg-sim-bounces at lists.onebuilding.org [mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Rimes, Christie
Sent: Thursday, November 19, 2009 1:32 PM
To: Steven Rutter; bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] Baseline Modeling for LEED

In  my experience you do not increase the baseline energy model as you are being awarded (gaining that point) when you achieve the ventilation credit. There are a few similar situations in LEED where by achieving one credit will prevent you from achieving another but this happens to everyone so it works out to be somewhat fair.

[cid:image001.png at 01CA6937.2E95D6D0]

From: bldg-sim-bounces at lists.onebuilding.org [mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Steven Rutter
Sent: Thursday, November 19, 2009 1:25 PM
To: bldg-sim at lists.onebuilding.org
Subject: [Bldg-sim] Baseline Modeling for LEED

All,
There is a credit in LEED (EQc2.0) that involves increasing the required ventilation rate by 30%.  In trying to achieve this credit, the amount of energy would have to increase to condition that additional 30% OSA.  Does anyone know if you are supposed to increase the baseline energy model's ventilation rate so it has the same ventilation rate as the proposed building?  Thank you in advance for your help.


Steven Rutter, LEED(r) AP, EIT

[cid:image002.jpg at 01CA6937.2E95D6D0]
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