Conventional physics does state it's possible!

[exnihiloest]

...
One square meter (3.28ft by 3.28ft) of surface at 297K (74.9F, 23.9F) radiates 441 watts. Both sides of that flat surface radiates 882 watts. The peak frequency of such blackbody radiation is 31THz (31e+12 Hz).
...

The problem is that such a surface is in thermal equilibrium with the environment. It absorbs the same quantity of energy as it radiates.
To extract this energy, we have to build a "diode" function for the energy, like a Maxwell demon.
Not simple.

[SchubertReijiMaigo]

Maxwell demon exist if you convert wasted ambiant heat into usefull energy like electricty: nano antenna can do this with infrared solar panel, the problem is to build a very rapid nanodiode to catch the teras hertz frequency: frequency of heat. Heat is not wasted energy it's a EM waves like radio light etc... The second law of thermodynamic is false in this case (microscopic and quantic level ), but true at macroscopic level... Humans can control with this the global warming problem.

[Nabo00o]

The problem is that such a surface is in thermal equilibrium with the environment. It absorbs the same quantity of energy as it radiates.
To extract this energy, we have to build a "diode" function for the energy, like a Maxwell demon.
Not simple.

I have proposed a way of doing it on this forum, search for maxwell's demon. Another one I haven't started a topic on is on black body radiation...

Julian