A vapor-compression system produces 20 tons of refrigeration using R12 as a refrigerant while operating between a condenser temperature of 41.6°c and an evaporator temperature of – 25°c. The superheat at the compression suction and the sub-cooling at the condenser outlet are 10°K. The pressure drop are 10kPa across the evaporator and the condenser. Determine the refrigerating effect in kJ per kilogram, the circulating rate of R12 in kilograms per second, the power required, the COP, the heat rejected in kW and the volume flow rate of refrigerant at compressor inlet conditions. 10° K subcooling 7 T=41.6° C h=C s=C Tevap =-25° C 10° K superheat

A vapor-compression system produces 20 tons of refrigeration using R12 as a refrigerant while operating between a condenser temperature of 41.6°c and an evaporator temperature of – 25°c. The superheat at the compression suction and the sub-cooling at the condenser outlet are 10°K. The pressure drop are 10kPa across the evaporator and the condenser. Determine the refrigerating effect in kJ per kilogram, the circulating rate of R12 in kilograms per second, the power required, the COP, the heat rejected in kW and the volume flow rate of refrigerant at compressor inlet conditions. 10° K subcooling 7 T=41.6° C h=C s=C Tevap =-25° C 10° K superheat

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

Chapter3: Refrigeration And Refrigerants

Section: Chapter Questions

Problem 2RQ: What are the approximate temperature ranges tor low-, medium-, and high-temperature refrigeration...

See similar textbooks

Similar questions

Condensers in these refrigerators are all_______cooled.
What are the approximate temperature ranges tor low-, medium-, and high-temperature refrigeration applications?
Refrigerators currently being manufactured in the United States are using______as their refrigerant.
For a 10-ton-capacity refrigeration system, the pressure of refrigerant in the evaporator is 150 kPa, whereas in the condenser it is 950 kPa. If refrigerant R-134a is used under saturated conditions, calculate the theoretical power required to operate the compressor = ... KW
A two stage cascade refrigeration system uses R-12 in the high pressure loop with a condenser temperature of 300C and -100C in the cascade condenser, and R-22 in the low pressure loop with a temperature in the cascade condenser of 00C and an evaporator temperature of -30 0C. Given that, h6 = 366 kJ/kg; h2= 421 kJ/kg. Determine the amount of ice (kg)for a 10 hrs operation if the initial temp of water is 31 0C to ice at --80C. ANSWER: 7358.9169 kg A two stage cascade refrigeration system uses R-11 as the working substance. The evaporator is at -30 0C and the high pressure condenser is at 300C. The cascade condenser is a direct contact type. The refrigeration load is 24 tons. Given that, h2 = 393 kJ/kg; h6 = 408 kJ/kg. Determine the ff: a.) amount ofwater for a 10 hrs operation if the initial temp of water is 34 0C to 20C. ANSWER: 22656.8019kg b.) amount of cooling water needed for a temp rise of 130C. ANSWER: 1.9446 c.) heat…
A two stage cascade refrigeration system uses R-12 in the high pressure loop with a condenser temperature of 300C and -100C in the cascade condenser, and R-22 in the low pressure loop with a temperature in the cascade condenser of 00C and an evaporator temperature of -30 0C. The refrigeration load is 24 tons. Given : h6 = 368 kJ/kg; h2= 420 kJ/kg Determine: 1) the mass flow rate in the low pressure loop in kg/s 2) mass flow rate in the high pressure loop, in kg/s 3) total power requirement in KW
A two stage cascade refrigeration system uses R-12 in the high pressure loop with a condenser temperature of 300C and -100C in the cascade condenser, and R-22 in the low pressure loop with a temperature in the cascade condenser of 00C and an evaporator temperature of -30 0C. The refrigeration load is 28 tons. Given : h6 = 366 kJ/kg; h2= 421 kJ/kg Determine: 1) the mass flow rate in the low pressure loop in kg/s 2) mass flow rate in the high pressure loop, in kg/s 3) total power requirement in KW 4.) COP 5.) heat rejected in the condenser, KW 6.) amount of cooling water needed for a temp rise of 140C. in kg/s 7.) amount of ice (kg)for a 10 hrs operation if the initial temp of water is 31 0C to ice at -80C. Answe in kg.
For a 10-ton-capacity refrigeration system, the pressure of refrigerant in the evaporator is 210 kPa, whereas in the condenser it is 750 kPa. If ammonia (R-717) is used under saturated conditions, calculate the theoretical power required to operate the compressor.
For a 10-ton-capacity refrigeration system, the pressure of refrigerant in the evaporator is 210 kPa, whereas in the condenser it is 800 kPa. If R-314a is used under saturated conditions, calculate the theoretical power required to operate the compressor.
Determine the degrees of subcooling at the exit of the condenser of a 2-ton air-conditioner system. The system operates on the ideal, vapor-compression refrigerationcycle with the following design parameters: R-134a flow rate 0.05 kg/s Evaporator Pressure 200 kPa Condenser Pressure 1200 kPa
Consider a two-stage compression refrigeration system operating between the pressure limits of 0.8 and 0.14 MPa. The working fluid is refrigerant-134a. The refrigerant leaves the condenser as a saturated liquid and is throttled to a flash chamber operating at 0.4 MPa. Part of the refrigerant evaporates during this flashing process, and this vapor is mixed with the refrigerant leaving the low-pressure compressor. The mixture is then compressed to the condenser pressure by the high-pressure compressor. The liquid in the flash chamber is throttled to the evaporator pressure, and it cools the refrigerated space as it vaporizes in the evaporator. Assuming the refrigerant leaves the evaporator as saturated vapor and both compressors are isentropic, determine (a)the fraction of the refrigerant that evaporates as it is throttled to the flash chamber, (b)the amount of heat removed from the refrigerated space and the compressor work per unit mass of refrigerant flowing through the condenser,…
A two-evaporatoor compression refrigeration system like that in the Figure below uses refrigerant-134a as the working fluid. The system operates evaporator 1 at 30 psia, evaporator 2 at 10 psia, and the condeser at 180 psia. The cooling load for evaporator 1 is 9000 Btu/h and that for evaporator 2 is 24,000 Btu/h. Determine the power required to operate the compressor and the COP of this system. The regrigerant is saturated liquid at the exit of the condenser and saturated vapor at the exit of each evaporator, and the compressor is isentropic.