Re: [EnergyPlus_Support] simulating a coat of reflective paints (cool roofs)

["'jeannieboef@xxxxxxxxx' jeannieboef@xxxxxxxxx [EnergyPlus_Support]" <EnergyPlus_Support@xxxxxxxxxxxxxxx>]

Solar radiation includes for all frequencies in the EMR-spectrum.
Thermal Absorbtance = Infrared (IR) spectrum (long-wave) which  
overlaps very slightly with some of the visual spectrum.

When we talk about the emissivity of a product, we usually refer to  
it's IR emissivity. This is because this bandwidth carries  
proportionally the most energy (by far) of all the bandwidths (that  
generally get absorbed by most materials) and accounts for a very  
large percentage of all absorbed solar radiation.

So how can it be that you have specified 0.90 for Thermal Absorbtion  
whilst visual and solar absorbtion are 0.2 (which I find  
unrealistically low)?

Usually the Thermal Absorbtion is the most important field and is at  
least similar to the Solar (because it has the heaviest energy  
weighting).

Mit freundlichen Grüßen- Sent from my iPhone (excuse the brevity)

i. A.
Jean Marais
b.i.g. bechtold
Tel.   +49 30 6706662-23

On 10.07.2014, at 06:11, "Asit Mishra asitkm76@xxxxxxxxx  
[EnergyPlus_Support]" <EnergyPlus_Support@xxxxxxxxxxxxxxx> wrote:

>     0.9,                     !- Thermal Absorptance
>     0.2,                     !- Solar Absorptance
>     0.2;                     !- Visible Absorptance


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Posted by: "jeannieboef@xxxxxxxxx" <jeannieboef@xxxxxxxxx>
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