  Interesting effects arise in cyclic machines where both heat and ergotropy
transfer take place between the energising bath and the system (the working
fluid). Such effects correspond to unconventional decompositions of energy
exchange between the bath and the system into heat and work, respectively,
resulting in efficiency bounds that may surpass the Carnot efficiency. However,
these effects are not directly linked with quantumness, but rather with heat
and ergotropy, the likes of which can be realised without resorting to quantum
mechanics.
