"The most important feature of an ideal cool roof is that its surface strongly reflects sunlight.
The surface of an ideal cool roof should also efficiently cool itself by emitting thermal radiation.
Thus, a cool roof should have both high ?solar reflectance? (ability to reflect sunlight, measured
on a scale of 0 to 1) and high ?thermal emittance? (ability to emit thermal radiation, also
measured on a scale of 0 to 1). The solar reflectance and thermal emittance of a surface are
called its ?radiative? properties because they describe its abilities to reflect solar radiation and
emit thermal radiation".
http://coolcolors.lbl.gov/assets/docs/fact-sheets/Cool-roof-Q%2BA.pdf
It means cool roof has both the properties i.e. Thermal reflectance and Solar Reflectance so according to this i need to consider both the values for cool Roof. Please guide me on this..
It means cool roof has both the properties i.e. Thermal reflectance and Solar Reflectance so according to this i need to consider both the values for cool Roof. Please guide me on this..
Regards!
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On Thu, Oct 4, 2012 at 12:09 PM, Jeremiah Crossett <jcrossett@xxxxxxxxxxxxxxx> wrote:
I thought Solar Absorptance was the key input for SRI-
Jeremiah D. Crossett | Senior Analyst | Phase Change Energy Solutions120 E. Pritchard St. | Asheboro, NC 27203 | Mobile 503-688-8951
On Thu, Oct 4, 2012 at 11:22 AM, Javed Iqbal <eee.javed@xxxxxxxxx> wrote:Hi,
I'm trying to see effect of roof reflectivity on Energy consumption and as per I/O guide there are two parameters Thermal absorptance and Visible absorptance which accounts the impact of reflectivity. Can anybody guide me on which value needs to be considered for high SRI/Reflectivity study.Thanks in Advance!--Javed Iqbal, LEED AP, CEAEnergy Analyst
--Javed Iqbal, LEED AP, CEAEnergy Analyst
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