In the disclosed Maxwell's demon type of experiment from 2012, heat from
ambient air was converted completely into electric energy, using a
static magnetic field without producing any other effect.
The phenomenon proves clearly that the second law of thermodynamics is
not universally valid, even though the output was tiny.
"Realization of Maxwell’s Hypothesis" A heat-electric conversion in
contradiction to Kelvin’s statement by Xinyong Fu, Zitao Fu Shanghai
Jiao Tong University