[BLDG-SIM] Design Air Flow Sizing per 90.1-2004 App G

[David S Eldridge]

There is an addendum, although the numbering in the addendum seems to have changed with a new section prior to this one...
 
http://www.ashrae.org/content/ASHRAE/ASHRAE/ArticleAltFormat/200661121930_347.pdf (see page 7-8)
 
Revise Section G4.2.3.12 as follows:

G4.2.3.1.2 Supply Air Temperature Reset (Systems 5 through 8).

The following is strikethrough:

Supply air temperature shall be reset based on

zone demand from the design temperature difference to a

10°F (5.6°C) temperature difference under minimum load

conditions. Design air flow rates shall be sized for the reset

supply air temperature; i.e., a 10°F (5.6°C) temperature difference.

Replacing with:

The air temperature for cooling shall be reset higher

by 5°F (2.3°C) under the minimum cooling load conditions.

 
David
 
--------------------------------------------------------------
David S. Eldridge, Jr.
Project Engineer
LEED v2.0 Accredited Professional
Grumman/Butkus Associates
820 Davis St., Suite 300
Evanston, IL  60201
847.328.3555  ext. 224
dse at grummanbutkus.com
-------------------------------------------------------------

 

________________________________

	From: BLDG-SIM at gard.com [mailto:BLDG-SIM at gard.com] On Behalf Of Paul Riemer
	Sent: Friday, July 07, 2006 12:06 PM
	To: BLDG-SIM at gard.com
	Subject: [BLDG-SIM] Design Air Flow Sizing per 90.1-2004 App G
	
	
	I would appreciate any clarifications that can be shared on the underlined sentences in these two excerpts from Appendix G of ASHRAE 90.1-2004.  They seem contradictory so I must be missing the author's intent.
	G3.1.2.8 Design Air Flow Rates. System design supply air flow rates for the baseline building design shall be based on a supply-air-to-room-air temperature difference of 20°F. If return or relief fans are specified in the proposed design, the baseline building design shall also be modeled with fans serving the same functions and sized for the baseline system supply fan air quantity less the minimum outdoor air, or 90% of the supply fan air quantity, whichever is larger.

	G3.1.3.12 Supply Air Temperature Reset (Systems 5 through 8). Supply air temperature shall be reset based on zone demand from the design temperature difference to a 10°F temperature difference under minimum load conditions. Design air flow rates shall be sized for the reset supply air temperature, i.e., a 10°F temperature difference.

	Thank you,

	Paul Riemer
	THE WEIDT GROUP
	952.938.1588
	PaulR at twgi.com
	 
	
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