Modeling cool roof

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All,

We need to model a cool roof ECM on an industrial complex.

I have researched the archives and did not find any guidance how to
accommodate the cool roof properties.

As a preamble lets me briefly describe how cool roof is characterized:

Cool roof thermal properties:

a. Solar Reflectance
b. Thermal Emittance.
c. R-Value

A Cool Roof Minimizes The Solar Heat Gain of a Building by First Reflecting
Incoming Radiation, Then by Re-emitting the Remaining Absorbed Portion.

Sun radiation hits the roof, the fraction of solar energy that is reflected
by the roof is called Solar Reflectance (SRI), some heat is absorbed by the
roof and transferred to the building.

The relative ability of the roof surface to radiate back absorbed heat is
termed Thermal Emittance.

Cool roofs increases substantially SRI and TE

As a Result, The Cool Roof Stays Cooler than a Traditional Roof of Similar
Construction.

Some cool roof products also has a layer of additional insulation

eQUEST currently has only R-Value to specify

Can someone please advise how can we take into account the SRI and TE as
well

Thanks,

Nathan Guedalia, CTO

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RTFM, equest allows you to define the exterior surface absorptance.

>> Christopher Jones, P.Eng.

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Cool roofs work to reduce the cooling load. For uncooled warehouses,
the cool roof serves to increase heating costs.

In southern Ontario, I have seen very few projects, with mechanical
cooling, where there is a net gain in energy savings when examining
"cool" roofs as an ECM. In most cases, the extra cost for the
reflective roof does not have a viable payback.

>> Christopher Jones, P.Eng.

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