Carnot Efficiency

A Carnot cycle with an Ideal Gas as
the working substance is shown
opposite. Heat is added to the
system at a high temperature, T_H ,
along the path A - B. Along B - C
the gas expands adiabatically and
does work on the piston. Heat is
removed from the gas in the iso-
thermal process C - D (T_L), and then the gas is compressed adiabatically to its initial condition along D - A.

The Carnot Efficiency = (Net Work)/ (Net Heat) = (Q_H - Q_L)/ Q_H = (T_H - T_L )/ T_H