Urban Rooftop Heat Reduction

Reed YK-80AM, Anemometer/thermometer, Metal Vane Probe.

Pocket Wind Meters and Weather Trackers by KESTREL – Air Velocity Meters and Anemometers by Zoro Tools Industrial Supplies.

LiveRoof®, the Horticultural Science Company, will Showcase its Superior Solution for Modular Green Roof Design at the International Roofing Expo (IRE).

https://www.ashrae.org/home/

http://www.nyserda.ny.gov/en/Funding-Opportunities/Current-Funding-Opportunities/PON-2606-Advanced-Buildings-Program.aspx

All Documents

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http://heatisland.lbl.gov/

Authors:

Ronnen Levinson a,n, Hashem Akbari a,1, Paul Berdahl a, Kurt Wood b, Wayne Skilton b, Jerry Petersheim b

2 paint layers for concrete til and asphalt shingles.

Each layer aqueous polyvinylidene fluoride (PVDF)/acrylic technology.

First layer white basecoat with weak absoroption and strong backscattering from 500 to 2000nm.

2nd layer color topcoat with weak NIR absorption and strong NIR backscattering.

Backscattering reverses the direction of the light and absorption converts light to heat.

45% of sunlight arrives in the visible spectrum.

Performance is evaluated based on how high S is for a given value of L or how low L is for given value of S.

S= solar reflectance
L=CIELAB tristimulus value of L* (lightness)

California offers rebates for installing reflective roofing. Steep sloped roofs must have a reflectance of .25 for a .10 ft^2 rebate. .40 is tier 2 rebate of .20/ft^2.

Rough surfaces are less reflective than smooth ones as part of the reflected light returns to the rough surface.

Authors:

P.H. Biwole a,b,c,*, M. Woloszyn a,b, C. Pompeo

Near optimum efficiency can be easily reached with a double-skin structure featuring a .15 emissive sheet iron, a 5cm thick insulation, 10cm cavity, and 30 deg. inclination.