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Credit for MERV-13 filter

asked 2014-11-19 10:39:02 -0600

iseryapin gravatar image

updated 2015-07-10 06:40:25 -0600

Energy Model for LEED EAp2 & EAc1. New Construction Warehouse. I'm using System-10 [Fossil Fuel Heat and Vent] for baseline - fan power is calculated as Pfan=CFM x 0.3. In proposed model I have MAU's with final filter MERV13. I want to take credit for pressure drop across filter (0.9 in w.c.) in proposed design, but neither 90.1-2007 nor addendum dn address how to properly account for it in the baseline. There is a way to account for it in systems 3-4 and systems 5-8, but not systems 1-2 nor 10-11. Can I take credit for MERV13 or not?  

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Welcome @iseryapin! - please edit your question to include tags for the software you're using along with some others, e.g. fan-power and leed. Thanks.

MatthewSteen gravatar image MatthewSteen  ( 2014-11-19 10:49:24 -0600 )edit

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answered 2014-11-21 17:14:02 -0600

nfonner gravatar image

I would say no. ASHRAE addendum AU to 90.1-2010 (ASHRAE 90.1-2013) actually includes a deduction (negative pressure drop adjustment) for systems without any central heating or cooling device as well as systems with electric resistance heating vs HW coils. Link to addendum

Commentary from Foreword of Addendum AU:

Adds a deduction for systems without any central heating or cooling device. Since the base-level fan power allowances include the assumption that those components are present, the deduction is warranted for those systems that do not include those component.

I've had trouble with this myself, but the project had exhaust fans driving the ventilation (automotive repair bays) so the fan powers were much closer, but still over the 0.3w/cfm. The bays did have quite a few overhead fans for non-mechanical cooling. That is really the only credit the fan power calculation allows for system 10 & 11 (9 & 10 in 90.1-2010). As far as what I see anyway.

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Asked: 2014-11-19 10:39:02 -0600

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Last updated: Nov 21 '14