The working fluid of a liquid-vapor cycle is 1kg of R-134a. The cycle operates between two pressures 100kPa and 1200kPa. • Process A-B: An isobaric compression at the high pressure to a saturated liquid. • Process B-C: An iso-entropic process from the high pressure to the low pressure. • Process C-D: An isobaric expansion at the low pressure to a saturated vapor. • Process D-A: An iso-entropic process from the low pressure to the high pressure. a) Make a table of the temperature, pressure, volume, internal energy, enthalpy, entropy and quality factor (T, P, V, U, H, S & x) at the start of each process. b) Make a table of the change in internal energy, heat flow, work done, change in enthalpy, and change in entropy (AU, Q, W, AH, AS) during each leg of the cycle. c) Draw well-labelled P-V & T-S diagrams (indicating lines of constant pressure, the saturation dome, heat flow, work, etc.) d) Calculate the coefficient of performance of the cycle (O. /W).

The working fluid of a liquid-vapor cycle is 1kg of R-134a. The cycle operates between two pressures 100kPa and 1200kPa. • Process A-B: An isobaric compression at the high pressure to a saturated liquid. • Process B-C: An iso-entropic process from the high pressure to the low pressure. • Process C-D: An isobaric expansion at the low pressure to a saturated vapor. • Process D-A: An iso-entropic process from the low pressure to the high pressure. a) Make a table of the temperature, pressure, volume, internal energy, enthalpy, entropy and quality factor (T, P, V, U, H, S & x) at the start of each process. b) Make a table of the change in internal energy, heat flow, work done, change in enthalpy, and change in entropy (AU, Q, W, AH, AS) during each leg of the cycle. c) Draw well-labelled P-V & T-S diagrams (indicating lines of constant pressure, the saturation dome, heat flow, work, etc.) d) Calculate the coefficient of performance of the cycle (O. /W).

Refrigeration and Air Conditioning Technology (MindTap Course List)

8th Edition

ISBN:9781305578296

Author:John Tomczyk, Eugene Silberstein, Bill Whitman, Bill Johnson

Publisher:John Tomczyk, Eugene Silberstein, Bill Whitman, Bill Johnson

Chapter28: Special Refrigeration Applications

Section: Chapter Questions

Problem 15RQ: Why is two-stage compression popular for extra-low-temperature refrigeration systems?

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