A reversible process is one that can be executed in the reverse direction with no net change in the system or the surroundings.
At the end of a forwards and backwards reversible process, both system and the surroundings are returned to their initial state.
No processes are reversible. However, reversible processes are theoretically the most efficient process.
All real process are irreversible due to irreversibilities.
COMMON SOURCES OF IRREVERSIBILITY
friction
Sudden expansion and compression
Hypothetical cycle consists of four process:
A) Two reversible isothermal processes
B) Two reversible adiabatic processes
Heat is absorbed to flow in working fluid by application of high temperature energy source during expansion, and flow out of fluid by the application of lower temperature energy sink during compression.
