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. h6 = 366 kJ/kg; h2= 421 kJ/kg Determine the ff: a.) the mass flow rate in the low pressure loop, ANSWER: 0.5097287949549 kg/s b.) the mass flow rate in the high pressure loop, ANSWER: 0.94987995754451 kg/s c.) total power requirement ANSWER: 32.1224 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. h6 = 366 kJ/kg; h2= 421 kJ/kg Determine the ff: a.) the mass flow rate in the low pressure loop, ANSWER: 0.5097287949549 kg/s b.) the mass flow rate in the high pressure loop, ANSWER: 0.94987995754451 kg/s c.) total power requirement ANSWER: 32.1224 KW

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

Chapter22: Condensers

Section: Chapter Questions

Problem 7RQ: When a standard-efficiency air-cooled condenser is used, the condensing refrigerant will normally be...

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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 28 tons. h6 = 366 kJ/kg; h2= 421 kJ/kg Determine the ff:a.) COPANSWER: 3.0647 b.) heat rejected in the condenser,ANSWER: 130.5704 kw c.) amount of cooling water needed for a temp rise of 140C. ANSWER: 2.2258 kg/s
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,…
Consider a two-stage compression refrigeration system operating between the pressure limits of 1.2 MPa and 0.16 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 0.7 MPa. Part of the refrigerant evaporates and the remainder 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. Assume that the refrigerant leaves the evaporator as saturated vapor and both compressors are isentropic. a) i) Determine the amount of heat removed from the refrigerated space ii) Determine the compressor work per unit mass of refrigerant flowing through the condenser b) Determine the coefficient of performance