[BLDG-SIM] "Cool Roofing"

Marcus Sheffer sheffer at paonline.com
Mon Oct 7 11:39:09 PDT 2002

Whenever we have modeled this in the Northeast we also have seen negligible 
savings using PowerDOE and others.

We have come to the conclusion that the savings depend upon the amount of 
roof insulation and type of building.  If we enter minimal insulation the 
effect of a white roof is larger especially in a cooling dominated 
building, high internal loads, etc.

If you are installing even moderate amounts of insulation (R15 or more) 
then the effect of a white roof in the Northeast is virtually nil for most 
any building type.

Now when it comes to the urban heat island effect it can have a 
tremendously positive impact . . . but that is another issue.

At 01:55 PM 10/07/2002 -0400, you wrote:
>Has anyone had any success modeling cool roofing options (i.e. reflective 
>or light colored surfaces) in PowerDOE?  So far, I have seen negligible 
>results from the adjustment of roof construction absorptance values 
>(emissivity is also known to play a role, but there is no input for this 
>in PowerDOE).  I have seen data showing cooling energy savings from 0.06 
>to 0.54 kWh/sqft/yr, depending on building type.  I am getting only a very 
>small fraction of this.  Data collected in the study was from facilities 
>in the southern and western US, and I work primarily on buildings in the 
>My questions:
>How well can I expect PowerDOE to simulate this?  Is there a better way to 
>simulate cool roofing?  Is the sun simply too low in the sky in New 
>England to yield substantial savings?
>Your thoughts are appreciated.
>Wade McLaughlin

Marcus B. Sheffer                          energy & environmental consulting
Energy Opportunities                     717-292-2636
1200 E Camping Area Road            Fax: 717-292-0585
Wellsville, PA USA 17365-9783        sheffer at sevengroup.com
a Seven Group member company    www.sevengroup.com

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