A simple air refrigeration system is used for an aircraft to take a load of 20 TR. The ambient pressure and temperature are 0.9 bar and 22 ∘C. The pressure of air is increased to 1 bar due to isentropic ramming action. The air is further compressed in a compressor to 3.5 bar and then cooled in a heat exchanger to 72 ∘C. Finally, the air is passed through the cooling turbine and then it is supplied to the cabin at a pressure of 1.03 bar. The air leaves the cabin at a temperature of 25 ∘C. Assuming isentropic process, find the COP and the power required in kW to take the load in the cooling cabin.

A simple air refrigeration system is used for an aircraft to take a load of 20 TR. The ambient pressure and temperature are 0.9 bar and 22 ∘C. The pressure of air is increased to 1 bar due to isentropic ramming action. The air is further compressed in a compressor to 3.5 bar and then cooled in a heat exchanger to 72 ∘C. Finally, the air is passed through the cooling turbine and then it is supplied to the cabin at a pressure of 1.03 bar. The air leaves the cabin at a temperature of 25 ∘C. Assuming isentropic process, find the COP and the power required in kW to take the load in the cooling cabin.

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

Chapter45: Domestic Refrigerators And Freezers

Section: Chapter Questions

Problem 2RQ: The operating condition for the single compressor in a household refrigerator is the lowest box...

See similar textbooks

Similar questions

Condensers in these refrigerators are all_______cooled.
Why is two-stage compression popular for extra-low-temperature refrigeration systems?
The operating condition for the single compressor in a household refrigerator is the lowest box temperature, which is typically A. 0F B. -20F C. 20F D. 40F
Q1/ In simple refrigeration system for residential refrigerator uses R134a, the evaporator temperature is -20C and the condenser temperature is 30C. The refrigerant enters the compressor as saturated vapor (x = 1). If the mass flowrate is 1 kg/s. Determine: 1. Compressor work (w). 2. Rejected heat from the condenser. 3. Refrigeration effect (RE). 4. Coefficient of Performance (COP).
A vapor-compression refrigeration system circulates refrigerant 134a at a rate of 0.15 kg/s. The refrigerant enters the compressor at -10 degrees Celcius and 100 kPa, and exits the compressor at 800 kPa. The isentropic efficiency of the compressor is 76%. Pressure drop through the condenser and evaporator are negligible. The refrigerant exits the condenser at 30 degrees Celcius and 800 kPa. Ignoring the heat transfer between the compressor and its surroundings, determine: The rate at which heat energy is removed from the refrigerated space in kW. The coefficient of perfromance.
Refrigerant R-134a enters the compressor of a refrigeration machine at 140 kPa pressure and -10°C temperature and exits at 1 MPa pressure. The volumetric flow of the refrigerant entering the compressor is 0.23 m3/minute. The refrigerant enters the throttling valve at 0.95 MPa pressure and 30°C, exiting the evaporator as saturated steam at -18°C. The adiabatic efficiency of the compressor is 78%. Show the cycle in the T-s diagram. a) Calculate the power required to start the compressor. b) Calculate the heat taken in a unit time from the cooled environment. COP=? c) Calculate between the evaporator and the compressor, how much the pressure of the refrigerant drops, and how much is the heat gain.
: Refrigerant 134a enters a compressor of a vapour compression of a refrigeration cycle at 120Kpa as a saturated vapour and leaves at 900 Kpa and 75oc. The refrigerant leaves the condenser as a saturated liquid. The rate of cooling provided by the system is 18000 Btu/hr. Determine (1) Mass flow rate of R134a (2) The Cop of the cycle (3) Also determine the Cop of the cycle if the expansion valve is replaced by an isentropic turbine. Do you recommend such a replacement for the refrigeration system? (4) Determine the Cop if the evaporator pressure is 160Kpa and otheer values remains the same. (5) Determine the Cop if the condenser pressure is 800 Kpa and other values remain the same.
An ammonia refrigeration compressor takes its suction from the evaporator at a temperature of -20oF (-28.9oC) and a quality of 95%. The compressor discharges at a pressure of 100 psi (689.5 kPa), liquid ammonia leaves condenser at 50oF (10oC). Properties of Ammonia: At 689.6 kPa (Tsat = 13.3oC) h = 1,568 kJ/kg; s = 5.7676 kJ/kg.K At 10oC: hf = 246.531 kJ/kg At -28.9oC by interpolation hf = 68.5 kJ/kg; hg = 1424.5 kJ/kg sf = 0.49366; sg = 6.0452Find the heat rejected by the evaporator in kJ/kg. a. 1,356.5 b. 1,568.5 c. 1,321.5 d. 1,125.5
An ammonia refrigeration compressor takes its suction from the evaporator at a temperature of -20oF (-28.9oC) and a quality of 95%. The compressor discharges at a pressure of 100 psi (689.5 kPa), liquid ammonia leaves condenser at 50oF (10oC). Properties of Ammonia: At 689.6 kPa (Tsat = 13.3oC) h = 1,568 kJ/kg; s = 5.7676 kJ/kg.K At 10oC: hf = 246.531 kJ/kg At -28.9oC by interpolation hf = 68.5 kJ/kg; hg = 1424.5 kJ/kg sf = 0.49366; sg = 6.0452Find the heat absorbed by the evaporator in kJ/kg.
An ammonia refrigeration compressor takes its suction from the evaporator at a temperature of -20oF (-28.9oC) and a quality of 95%. The compressor discharges at a pressure of 100 psi (689.5 kPa), liquid ammonia leaves condenser at 50oF (10oC). Properties of Ammonia: At 689.6 kPa (Tsat = 13.3oC)      h = 1,568 kJ/kg; s = 5.7676 kJ/kg.K At 10oC:      hf = 246.531 kJ/kg At -28.9oC by interpolation      hf = 68.5 kJ/kg; hg = 1424.5 kJ/kg             sf = 0.49366; sg = 6.0452Find the horsepower per ton of refrigeration. a. 1.044 b. 0.987 c. 1.404 d. 0.897
An ammonia refrigeration compressor takes its suction from the evaporator at a temperature of -20oF (-28.9oC) and a quality of 95%. The compressor discharges at a pressure of 100 psi (689.5 kPa), liquid ammonia leaves condenser at 50oF (10oC). Properties of Ammonia: At 689.6 kPa (Tsat = 13.3oC)      h = 1,568 kJ/kg; s = 5.7676 kJ/kg.K At 10oC:      hf = 246.531 kJ/kg At -28.9oC by interpolation      hf = 68.5 kJ/kg; hg = 1424.5 kJ/kg             sf = 0.49366; sg = 6.0452Find the COP. a. 4 b. 4.25 c. 5 d. 5.25
An ammonia refrigeration compressor takes its suction from the evaporator at a temperature of -20oF (-28.9oC) and a quality of 95%. The compressor discharges at a pressure of 100 psi (689.5 kPa), liquid ammonia leaves condenser at 50oF (10oC). Properties of Ammonia: At 689.6 kPa (Tsat = 13.3oC)      h = 1,568 kJ/kg; s = 5.7676 kJ/kg.K At 10oC:      hf = 246.531 kJ/kg At -28.9oC by interpolation      hf = 68.5 kJ/kg; hg = 1424.5 kJ/kg      sf = 0.49366; sg = 6.0452 Determine the quality of refrigerant upon entering to the evaporator.