[Bldg-sim] Exhaust, outside air and infiltration for LEED

[Bishop, Bill]

The hoods are more "effective" really, not more efficient. They have no
fans, but are designed to effectively remove fumes with a lower flow
rate through them. All the hoods are connected to a central exhaust fan
system.

 

Now that you mention it, I guess I need to go back and add fan energy in
my baseline. The baseline has several systems (one per zone as required
in 90.1) where the proposed only has two air handlers and a common
exhaust fan. I will add a return fan with Pfan power (per G3.1.2.9) for
every system that serves a zone that, in the proposed design, is
connected to the common exhaust.

 

Bill

________________________________

From: Michael Tillou [mailto:michael.tillou at gmail.com] 
Sent: Friday, November 07, 2008 2:53 PM
To: Bishop, Bill; bldg-sim at lists.onebuilding.org
Subject: RE: [Bldg-sim] Exhaust, outside air and infiltration for LEED

 

You are correct that Appendix G requires outside air to be the same for
both as-designed and baseline models.  You would not be able to claim
savings for reduced ventilation airflow from a more efficient fume hood.
Similarly you cannot claim credit for reduced ventilation airflow on
displacement ventilation and UFAD systems. 

 

However I see no reason why you wouldn't be able to claim the fan energy
savings associated with a more efficient fume hood.

 

Mike

 

Michael Tillou, PE, LEED

Tillou Engineering, LLC

Williamstown, MA 01267

P: 413-458-9870 C: 413-652-1087

________________________________

From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Bishop,
Bill
Sent: Friday, November 07, 2008 9:04 AM
To: bldg-sim at lists.onebuilding.org
Subject: [Bldg-sim] Exhaust, outside air and infiltration for LEED

The mechanical engineer for a campus laboratory building with 100% OA
wants to claim energy savings for reduced exhaust from more efficient
fume hoods. (Established design practice uses hoods with 100 fpm flow -
they are installing 70 fpm hoods. This reduces peak exhaust from 700 to
490 CFM per hood.) My approach has always been to keep outside air,
exhaust and infiltration flows identical between the proposed and
baseline models (except for DCV). (This was not easy for this model with
proposed VAV and baseline constant volume packaged rooftops.)

 

Has anybody successfully claimed OA/exhaust/infiltration savings for a
LEED project?

 

Thanks,

Bill

 

William Bishop, EIT, LEED(r) AP | Pathfinder Engineers LLP

Mechanical Engineer

 

3300 Monroe Ave., Suite 306 
Rochester, NY  14618

TEL (585) 218-0730 Ext. 114
FAX (585) 218-0737 

bbishop at pathfinderengineers.com

 

www.pathfinderengineers.com

P Please consider the environment before printing this email

 

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