Thermal Radiation Energy transfer

AI Thread Summary
The discussion centers on understanding net thermal radiation, specifically how Pnet can be negative when the environmental temperature exceeds the object's temperature. It is clarified that incoming radiation can possess more energy than outgoing radiation, leading to a negative net value. A key point raised is that the original equation presented in a book contained an error, with the temperatures incorrectly flipped. This misrepresentation contributed to confusion regarding the calculation of net thermal radiation. Accurate comprehension of the equation is essential for correctly interpreting thermal radiation dynamics.
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I have a general question regarding Radiation. If the net Thermal Radiation is understood to be :

Pnet = Pabs - Prad= σϵA(Tenv^4 - T^4) . How is it that Pnet is negative if the environmental temp is higher than the temp of the object?
 
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Awer1 said:
I have a general question regarding Radiation. If the net Thermal Radiation is understood to be :

Pnet = Pabs - Prad= σϵA(Tenv^4 - T^4) . How is it that Pnet is negative if the environmental temp is higher than the temp of the object?

Because the incoming radiation has more energy than the outgoing radiation. I can't see what the problem is.
 
I figured it out with some help, the equation in the book and their website had the equation wrong.. the book had the temperatures flipped
 
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