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Radiation - Solar Loads - Material properties

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Old   November 9, 2015, 10:59
Default Radiation - Solar Loads - Material properties
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Hi everybody,

i try to simulate the irradiation on a solar thermal collector.
After activating radiation>s2s radiation>solar loads i am now struggeling with the "Physics Values" for the surface where the energy should be absorbed. Basically it is a alloy plate and i can change the "Emissivitiy" and "Transmissivity" of the selected "Boundary".
I am wondering why it is not possible to specify the "absortion coefficient".
Can anyone please help because at the moment i have no idea how to prescribe the absorption on that surface.

Thanks a lot!
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Old   November 9, 2015, 14:29
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Transmissivity, reflectivity, and absorption are all coefficients that must add to 1. You can specify transmissivity and reflectivity to give you a certain absorption.
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Old   November 10, 2015, 02:43
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Thanks! I was trying it that way but the plate is not heating up at all. Maybe i should use the the multiband thermal radiation instead of the gray thermal radiation so i can define the tranmissivity etc. for different wave lengths. I was just wondering because there was no increase in temperature..
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Old   November 10, 2015, 11:05
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Perhaps your boundary is just in shadow? If you plot the boundary irradiation is it nonzero?
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Old   November 11, 2015, 09:04
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Ok, now it is working. Thanks
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