  We construct a quantum critical Otto engine that is powered by finite
temperature baths. We show that the work output of the engine shows universal
power law behavior that depends on the critical exponents of the working
medium, as well as on the temperature of the cold bath. Furthermore, higher
temperatures of the cold bath allows the engine to approach the limit of
adiabatic operation for smaller values of the time period, while the
corresponding power shows a maximum at an intermediate value of the cold bath
temperature. These counterintuitive results stems from thermal excitations
dominating the dynamics at higher temperatures.
