2. In an ammonia vapor compression refrigeration cycle, 5 kg/min of refrigerant are circulated. The evaporating temperature of the cycle is designed at -18°C, and the refrigeration engineer decided to consider to superheat the ammonia as it leaves the evaporator by 5°C; the compressor discharge is at 12 bars, 125°C. The ammonia leaves the condenser as saturated liquid. Assume no pressure drop happens as the refrigerant flows in the system. Sketch the Ph and Ts diagram and find, a. Volume flow rate, m3/sec b. Capacity, tons c. Work, hp d. The compressor efficiency.

2. In an ammonia vapor compression refrigeration cycle, 5 kg/min of refrigerant are circulated. The evaporating temperature of the cycle is designed at -18°C, and the refrigeration engineer decided to consider to superheat the ammonia as it leaves the evaporator by 5°C; the compressor discharge is at 12 bars, 125°C. The ammonia leaves the condenser as saturated liquid. Assume no pressure drop happens as the refrigerant flows in the system. Sketch the Ph and Ts diagram and find, a. Volume flow rate, m3/sec b. Capacity, tons c. Work, hp d. The compressor efficiency.

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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Similar questions

Why is two-stage compression popular for extra-low-temperature refrigeration systems?
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A refrigerant 22 vapor compression system includes a liquid-to-suction heat exchanger in the system. The heat exchanger cools the saturated liquid from the condenser from 32°C to 21°C with vapor which comes from the evaporator at -10°C. The compressor is capable of pumping 20 L/sec of refrigerant. What is the enthalpy of the refrigerant at the suction of the compressor neglecting the heat exchanger? What is the isenthalpic value of the refrigerant in the system neglecting the heat exchanger? What is the refrigerant's enthalpy after compression? What is the COP of the system neglecting the heat exchanger? What is the enthalpy of the refrigerant before it enters in the expansion valve? What is the approximate enthalpy of the refrigerant at the suction of the compressor? What is the estimated enthalpy of the refrigerant after compression? What is the COP of the system? What is the refrigerating capacity of the system in TOR if: a.) without hex and b.) with hex?
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100 ton of vapor compression refrigeration system using R-134a the vapor entering the evaporator at 2 bar and entering the condenser at 10 bar, the pressure drops in suction valve and discharge valve equal to 0.25 bar and 1.0 bar respectively. assume the refrigerant leaving the evaporator and condenser at saturated line find: (1) Refrigeration Effect (2) Power required in compressor (3) Actual COP of the cycle (4) Ideal COP of the cycle
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Q/ Refrigeration system operates on a vapor - compression cycle with R-134a as the working fluid. The refrigerant enter the compressor as superheated vapor at 0.1 Mpa and is compressed to 1 Mpa .The superheat and subcooling are 10 C°. Mass flow rate of refrigerant is 0.05 kg/s. Determine :- x4, Qe, Qc, Wc & C.O.P.
b. A refrigerating system using Freon-12 has an evaporator saturation temperature of - 25°C and a condenser saturation temperature of 35°C. The vapor is dry saturated at entry to the compressor and has a temperature of 65°C after compression to the condenser pressure. There is no undercooling of the liquid in the condenser. i. Calculate the input power required by the compressor per kW of refrigeration. ii. Calculate the COPRef of the refrigerating system. ii. Show the operating cycle of the refrigerating system on a T-s diagram.
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A refrigeration system operated on an ideal vapor-compression using R-12 with a vaporizing temperature of -10 degrees Celsius and a condensing temperature of 30 degrees Celsius, it requires 15 hp to drive the motor of the compressor. Find the ff: Enthalpies at each point of the cycle in kJ/kg Refrigerating Capacity in TOR • Mass of the Refrigerant in kg/s Percent Quality in the mixture Heat Rejected in kW Coefficient of Performance • Schematic and P-h Diagram