A piston/cylinder has 5m of liquid 20°C water on top of piston with cross-sectional area of 0.1 m2. Air is let in under the piston that rises and pushes the water out. Find the necessary work to push all the water out.

Available Energy, Availability and Irreversibility topics include: Reversible process, energy quality, useful work, availability, gouy stondola theorem, second law efficiency and comments on exergy. Availability and irreversibility are two key concepts in thermodynamics. Availability is the maximum amount of useful work that can be obtained from a system. It is also known as exergy.  Irreversibility is the inevitable loss of energy that occurs during a thermodynamic process. It is also known as energy destruction.  Irreversible processes lead to a decrease in the availability of energy.... Show more

Available Energy, Availability and Irreversibility topics include: Reversible process, energy quality, useful work, availability, gouy stondola theorem, second law efficiency and comments on exergy.

Availability and irreversibility are two key concepts in thermodynamics. Availability is the maximum amount of useful work that can be obtained from a system. It is also known as exergy. 

Irreversibility is the inevitable loss of energy that occurs during a thermodynamic process. It is also known as energy destruction. 
Irreversible processes lead to a decrease in the availability of energy. This is because some of the energy that enters the system is lost as waste heat. 

Unavailable energy 
Unavailable energy is the energy that cannot be utilized for doing useful work. It is also known as anergy. 

The second law of thermodynamics states that it is not possible to convert all the heat absorbed by a system into work.

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