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0.75 kg of refrigerant-134a at 120 kPa and 20°C initially fills a piston-cylinder device. Heat is...

0.75 kg of refrigerant-134a at 120 kPa and 20°C initially fills a piston-cylinder device. Heat is now transferred to the refrigerant from a source at 150°C, and the piston which is resting on a set of stops, starts moving when the pressure inside reaches 140 kPa. Heat transfer continues until the temperature reaches 90°C. Assuming the surrounding to be at 25°C and 100 kPa, determine (a) the work done, (b) the heat transfer, (c) the exergy destroyed, and (d) the second law efficiency of this process.

Engineering   Mechanical-Engineering   
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Answer #1

To solve this question we need to use property table of R134a refrigerant.

here not that we can not use constant specific heat capacity values of R134a because in process pressure and volume both varies with temperature.

see below the complete solution.

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