A piston-cylinder device initially contains 1.4 kg of refrigerant-134a at 100 kPa and 20oC. Heat is now transferred to the refrigerant from a source at 150oC, and the piston, which is resting on a set of stops, starts moving when the pressure inside reaches 120 kPa. Heat transfer continues until the temperature reaches 80oC. Assuming the surroundings to be at 25oC and 100 kPa, determine the second- law efficiency of this process.

Q: A piston–cylinder device initially contains 1.4 kg of refrigerant-134a at 100 kPa and 20°C. Heat is…

A: Given data

Q: Air enters a compressor at ambient conditions of 100 kPa and 20°C at a rate of 6.2 m3 /s with a low…

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Q: What is the second-law efficiency? How does it differ from the first-law efficiency?

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Q: and 25oC with a velocity of 30 m/s and exits at 1.8 MPa and 400oC. The compressor

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Q: Consider a rigid vessel that is initially empty, connected by a valve to a feed line of water at 1…

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Q: 2. During some actual expansion and compression processes in piston-cylinder devices, the gases have…

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Q: During some actual expansion and compression processes in piston–cylinder devices, the gases have…

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Q: Steam is condensed in a closed system at a constant pressure of 75 kPa from a saturated vapor to a…

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Q: Two rigid tanks are connected by a valve. Tank A is insulated and contains 0.3 m of steam at 400 kPa…

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Q: Refrigerant-134a enters the evaporator coils placed at the back of the freezer section of a…

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Q: Air enters a 36-cm diameter pipe steadily at 400 kPa and 40°C with a velocity of 8 m/s. Air is…

A:

Q: An insulated piston–cylinder device contains 0.05 m3 of saturated refrigerant- 134a vapor at 0.8-MPa…

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Q: Explain the Reversible work relations for steady-flow and closed systems.

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Q: Refrigerant 134-a enters the evaporator coils placed at the back of the freezer section of a…

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Q: What is a second law efficiency? How does it differ from a first law efficiency?

A: As per the guidelines, 1st question is answered.

Q: Under what circumstances can the entropy of a system decrease for a spontaneous process?

A: Whenever there is some heat rejection from the system the entropy of the system decreases.

Q: Steam enters a turbine at 6 MPa and 450°C at a rate of 33 kg/s and exits at 50 kPa as saturated…

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Q: A house that is losing heat at a rate of 35,000 kJ/h when the outside temperature drops to 4°C is to…

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Q: An adiabatic piston-cylinder device equipped with a spring maintains the pressure inside at 300 kPa,…

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Q: 5. During some actual expansion and compression processes in piston-cylinder devices, the gases have…

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Q: Steam enters a turbine steadily at 3 MPa and 450°C at a rate of 8 kg/s and exits at 0.2 MPa and…

A:

Q: Air enters the compressor of a gas-turbine plant at ambient conditions of 100 kPa and 25°C with a…

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Q: Is it possible for the entropy change of a closed system to be zero during an irreversible process?…

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Q: Air enters the compressor of a gas-turbine plant at ambient conditions of 100 kPa and 25°C with a…

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Q: A piston–cylinder device initially contains 1.4 kg of refrigerant-134a at 100 kPa and 20°C. Heat is…

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A:

Q: A 0.06-m3 rigid tank initially contains refrigerant- 134a at 0.8 MPa and 100 percent quality. The…

A:

Q: A 0.05-m3 rigid tank initially contains refrigerant134a at 0.8 MPa and 100 percent quality. The tank…

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Q: A piston–cylinder device initially contains 1.4 kg of refrigerant-134a at 100 kPa and 20°C. Heat is…

A: Given data m=1.4 kgP1=100 kPaT1=20°cP2=120 KPa

Q: 2. Refrigerant-134a is to be cooled by water in a condenser. The refrigerant enters the condenser…

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Q: Two rigid tanks are connected by a valve. Tank A is insulated and contains 0.3 m3 of steam at 400…

A: Dear student, we are suppose to solve only 3 sub parts. Please post other parts as a separate…

Q: Determine the work required (in kJ/kg) for a pump that is used to increase the pressure of a liquid…

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Q: Air enters a compressor at 14.7 psia and 77°F and is compressed to 140 psia and 200°F. Determine the…

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Q: 6. An insulated piston-cylinder device contains 0.05 m3 of saturated refrigerant- 134a vapor at…

A:

Q: Refrigerant-134a is compressed steadily from the saturated vapor state at 120 kPa to 1.6 MPa and 60…

A:

Work and Heat Transfer

It is generally related to thermal engineering which tells about the use, creation, conversion and transfer of heat energy between the systems. It is also considered that to transfer heat from one source to another, transfer of masses is also required. There are various mechanisms by which, transfer of heat takes place i.e. thermal conduction, convection, radiation or by change of phase. All these mechanisms have their own specific features which sometimes occur simultaneously within the same system.