[Equest-users] LEED Increased Ventilation Credit and Energy Modeling

[Alex Krickx]

Great comments all, and correct for LEED v3.

This is changing in the new LEED v4. It references ASHRAE 90.1 2010 which
does *not *match the baseline Ventilation rate to a proposed design that
exceeds the rates set by the rating authority or building official.

This matches Jim's comments - a high ventilation rate will be penalized
under LEED v4, since the baseline is the minimum, and the proposed matches
the higher value of the design.

Cheers,
Alex

*Alex Krickx* | LEED AP
Project Engineer
*Integral Group *| 427 13th Street | Oakland CA USA 94612
T 510.663.2070 x 247
integralgroup.com <http://www.integralgroup.com/> | *akrickx at integralgroup.com
<akrickx at integralgroup.com>*

*Trust* | *Nurture* | *Inspire*

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On Fri, Mar 7, 2014 at 6:47 AM, Robby Oylear <robbyoylear at gmail.com> wrote:

> Joe,
>
> Your last bit there about taking credit for constant OA flow from
> full-load to part-load conditions on a VAV system is a bit of a red flag
> for me.  The Baseline system should be minimally compliant with ASHRAE
> 62.1.  ASHRAE 62.1 section 6.2.6.1 requires that ventilation systems shall
> be designed to be capable of providing the required ventilation rates in
> the breathing zone including all full- and part-load conditions.  Outside
> of Demand Control Ventilation scenarios, I would always expect the Baseline
> and Proposed case to deliver the same outside airflow at all hours.
>
> That being said, I'm not certain how you're actually getting a credit for
> what you're saying.  What input are you modifying in eQUEST to accomplish
> proportional outside air flow control?
>
> -Robby
>
>
> On Thu, Mar 6, 2014 at 1:48 PM, Joseph Lewis <
> jlewis at fortierengineering.com> wrote:
>
>>   You are going to follow 90.1 Appendix G for the model.  This means
>> both the baseline and proposed design outdoor air flow rates will need to
>> be the same except if you are using demand control ventilation in the
>> proposed and it is not required by 90.1 section 6.
>>
>> In the case where you have demand controlled ventilation in the proposed
>> and it is not required in the baseline then the USGBC has stated that they
>> would like the baseline to be modeled as compliant with 62.1 without the
>> system level corrections.  There also should not be any temperature
>> difference corrections because the other appendix G rules require your CFM
>> sizing to be based up on a 20 °F delta T.
>>
>> If demand controlled ventilation is required by 90.1 then it must be
>> modeled in the baseline and proposed with the same design flow.
>>
>> I personally take credit on my models for where the proposed VAV system
>> has controls to maintain a constant OA flow across from design to minimum
>> supply, by modeling the baseline as just proportional.  I have not been
>> flagged for it, but I also have not found any definitive ruling that what I
>> am doing is allowed.
>>
>> Joe Lewis
>> Fortier Engineering
>>
>>  *From:* Joe Chappell <JoeC at designengineers.com>
>> *Sent:* Thursday, March 06, 2014 3:50 PM
>> *To:* mailto:equest-users at lists.onebuilding.org<equest-users at lists.onebuilding.org>
>> *Subject:* [Equest-users] LEED Increased Ventilation Credit and Energy
>> Modeling
>>
>>
>> Good day,
>>
>>
>>
>> I have a question regarding the LEED credit for Increased Ventilation
>> (IEQc2).  This is the credit awarded for exceeding ventilation in all
>> spaces by 30% beyond the ASHRAE standard 62.1 requirements.  It seems
>> obvious that the design model ventilation rates would be those 30% higher
>> than 62.1 requirements.  What then would the baseline model ventilation
>> rates be?
>>
>>
>>
>> If you strictly follow 90.1 Appendix G, you should always model baseline
>> and proposed equivalent except for when taking credit for demand controlled
>> ventilation.  However, it seems in this case that it could also be argued
>> (by LEED) that you should model the ASHRAE 62.1 required ventilation rates
>> in the baseline model, not those that are 30% higher and therefore pay the
>> energy expense( most climates) for increased outside air.
>>
>>
>>
>> Does anyone have any experience with LEED on this issue?  Thanks in
>> advance.
>>
>>
>>
>> Kind regards,
>>
>> *Joe Chappell*
>>
>>
>>
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