[BLDG-SIM] Cool Roof simulation

[Vikram Sami]

John,
Did you try changing the absorptance? Actually desired emissivity in
roofs works kind of reverse to windows. A cool roof should have high
emissivity numbers (allowing it to radiate heat and not convert that
heat to a temperature rise). A common misconception is that energy star
roofs are Low-E. Low-E roofs should actually heat up more than a high-E
roof.

Try changing the absorptance numbers and see if that affects your
simulation. 

Vikram Sami, LEED AP
Direct Phone 404-253-1466 | Direct Fax 404-253-1366

LORD, AECK & SARGENT ARCHITECTURE
Responsive Design * Technological Expertise * Exceptional Service
www.lordaecksargent.com



-----Original Message-----
From: BLDG-SIM at GARD.COM [mailto:BLDG-SIM at GARD.COM] On Behalf Of Aulbach,
John
Sent: Monday, October 16, 2006 4:24 PM
To: BLDG-SIM at GARD.COM
Subject: [BLDG-SIM] Cool Roof simulation

 
Hello All:

I am looking for a fairly straight forward to model a "Cool Roof" in
eQuest.

My general understanding would be to do a Parametric Run, changing the
outside emissivity from, say 0.75 to 0.3. But I am getting VERY little
energy benefit.

My building is a 140,000 sf office, 2-story (70,000 sf roof). It has a
CW VAV system with HW reheat, and return air is through ceiling plenums.

I am only seeing about a 50,000 kWh saving out of 11,000,000 kWh HVAC
usage.

Any experience, suggestions?

John R. Aulbach, PE, CEM
Project Manager
Nexant, Inc.
100 North Barranca, Suite 820
West Covina, CA 91791 USA
Phone: 626-430-9054
Fax: 626-430-9060
email: jaulbach at nexant.com
 

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