The discussion centers on the principles of heat transfer, specifically the mechanisms of conduction, convection, and radiation. It establishes that while heat transfer through conduction and convection typically occurs from hot to cold, radiation allows for heat transfer from cold to hot under specific conditions, as described by the Stefan-Boltzmann law. The conversation highlights that both bodies emit photons, and the net energy transfer is influenced by their temperatures. The concept of Maxwell's demon is referenced to illustrate the theoretical possibility of heat flow from cold to hot, although it requires work input to occur spontaneously.
PREREQUISITESStudents of physics, engineers in thermal management, researchers in thermodynamics, and anyone interested in the principles of heat transfer and energy dynamics.
You are correct. However, the odds of that happening are very very very small.MrXow said:It has never been observed not to flow from hot to cold but there is no law that says it cannot
Yes, so let's answer it:Shooting star said:The OP is asking about radiant heat. Read his query.
MrXow said:Heat can flow from cold to hot,
http://en.wikipedia.org/wiki/Maxwell's_demon
there is no law that says it cannot.
russ_watters said:Yes, so let's answer it:
Radiation between a cold and a hot object involves both objects radiating photons towards each other, but since the hot object is hotter, it radiates more (via the Stefan-Boltzmann law) and the net energy transfer is from the hot object to the cold one. How much is determined by plugging both temperatures into the equation.