A thermodynamic cycle is a series of thermodynamic processes
which returns a system to its initial state. Properties depend
only on the thermodynamic state and thus do not change over a
cycle. Variables such as heat and work are not zero over a
cycle, but rather depend on the process. The first law of
thermodynamics dictates that the net heat input is equal to the
net work output over any cycle. The repeating nature of the
process path allows for continuous operation, making the cycle
an important concept in thermodynamics. Two primary classes of
thermodynamic cycles are power cycles and heat pump cycles.
Power cycles are cycles which convert some heat input into a
mechanical work output, while heat pump cycles transfer heat
from low to high temperatures using mechanical work input.
Thermodynamic power cycles [change] Thermodynamic power cycles
are the basis for the operation of heat engines, which supply
most of the world's electric power and run almost all motor
vehicles. Power cycles can be divided accordi