Exercise 6.1 (20%) Refrigerant R-134a at 700 kPa and 70°C (condition 1) is cooled/condensed at constant pressure using cooling water in a condenser (heat exchanger). The refrigerant (R-134a) flows out of the condenser at 6.69°C subcooled at 700 kPa (state 2). The conditions of the cooling water at the inlet and outlet of the heat exchanger are 150 kPa, 15°C (condition 3) and 150 kPa, 25°C (condition 4). The mass flow of the cooling water is 10 kg/min a) Draw a sketch of the device (remember to put numbers for conditions and relate to these in your use of symbols) and calculate the mass flow of refrigerant R-134a in kg/min. b) How much heat power is transferred between the fluids in KW?

Exercise 6.1 (20%) Refrigerant R-134a at 700 kPa and 70°C (condition 1) is cooled/condensed at constant pressure using cooling water in a condenser (heat exchanger). The refrigerant (R-134a) flows out of the condenser at 6.69°C subcooled at 700 kPa (state 2). The conditions of the cooling water at the inlet and outlet of the heat exchanger are 150 kPa, 15°C (condition 3) and 150 kPa, 25°C (condition 4). The mass flow of the cooling water is 10 kg/min a) Draw a sketch of the device (remember to put numbers for conditions and relate to these in your use of symbols) and calculate the mass flow of refrigerant R-134a in kg/min. b) How much heat power is transferred between the fluids in 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

Chapter45: Domestic Refrigerators And Freezers

Section: Chapter Questions

Problem 13RQ: Condensers in these refrigerators are all_______cooled.

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Exercise 6.1 (20%) Refrigerant R-134a at 700 kPa and 70°C (condition 1) is cooled/condensed at constant pressure using cooling water in a condenser (heat exchanger). The refrigerant (R-134a) flows out of the condenser at 6.69°C subcooled at 700 kPa (state 2). The conditions of the cooling water at the inlet and outlet of the heat exchanger are 150 kPa, 15°C (condition 3) and 150 kPa, 25°C (condition 4). The mass flow of the cooling water is 10 kg/min a) Draw a sketch of the device (remember to put numbers for conditions and relate to these in your use of symbols) and calculate the mass flow of refrigerant R-134a in kg/min. b) How much heat power is transferred between the fluids in kW? Exercise 6.2 (30%) Subcooled water first flows through an adiabatic choke valve and then into an adiabatic separator. Before the throttle valve, the water is at 5 MPa and 180°C and the mass flow is 200 kg/s. The throttle valve reduces the pressure to 300 kPa. This is also the pressure in the mass flows…
Steam is supplied to a two-stage turbine at 48 bar and 400 °C. It expands in the firstturbine until it is just dry saturated, then it is re-heated to 400 °C and expandedthroughthe second-stage turbine. The condenser pressure is 0.04 bar. Determine the specific work output of the system to 3 d.p? what is the specific entalphy in kJ/kg for state 2?
An ammonia refrigeration compressor takes its suction from the evaporator, at a temperature of-200F and a quality of 95%. The compressor discharges at a pressure of 100 psi, liquid ammonia leaves the condenser at 500F.(a)Determine the heat absorbed by the evaporator in kJ/kg. (b)Determine the heat rejected to the condenser in kJ/kg. (c)Determine the COP. (d)Determine the horsepower per ton of refrigeration. (e)Determine the quality of refrigerant upon entering to the evaporator
Thermodynamic course question
A compressor serves two evaporators, one providing 5 tons of cooling at -20 degree F and the other, 10 tons of cooling at 10F. The system is a vapor-compression refrigeration system using R-12 with the condenser pressure at 200 psia. Assume saturated conditions leaving the condenser and evaporators and isentropic compression. Determine (a) the refrigerant flow through each evaporator, (b) the R-12 state entering the compressor, and (c) the compressor power.
The large insulated flash chamber of a vacuum refrigeration plant is kept at low temperatureby a steam jet which pumps vapor to a condenser . The condensate pump removes thecondensate formed and an air ejector discharges air from the condenser to an air vent .Warm water returns enters the flash chamber at 13 deg C ; chilled water leaves the flashchamber at 4 deg C . The vapor leaving the flash chamber has a dryness factor of 97% andthe condenser inside temperature is 32 deg C . For 100 tons of refrigeration , determine thequantity in cubic meter per minute of chilled water at 4 deg C that the system can provide .A) 0.45 B) 0.56 C) 9.33 D) 0.75
Saturated steam at 40∘C is to be cooled to saturated liquid in a condenser. The mass flow rate of the steam is 17.3 kg/s . Assume no pressure loss. a)Determine the rate of heat transfer. Q = ? MW
A plant using R134a refrigerant has a cooling capacity of 352 kW of refrigeration. It evaporates at 0 Cand condenses at 35 C, with the 5 of superheat at the evaporator outlet and 5 K of sub-cooling at the condenser outlet. Assuming isentropic compression and ignoring pressure drops in the piping, the evaporator and condenser, determi the following; a) The refrigeration effect b) The mass flow rate of refrigerant ) The compressor power d) The rate of heatrejection at the condenser e) The COP 0 The corresponding Carnot COP g) The percentage Carnot-efficiency
Aa 3. A vapour compression refrigeration system of 2400 kJ/min capacity works at an evaporator temperature of 263 K and a condenser temperature of 303 K. The refrigerant used is R-12 and is subcooled by 6°C before entering the expansion valve and vapour is superheated by 7°C before leaving the evaporator coil. The compression of refrigerant is reversible adiabatic. The refrigeration compressor is two-cylinder, single acting with stroke equal to 1.25 times the bore and runs at 1000 r.p.m. Determine: 1. Refrigerating effect per kg ; 2. Mass of refrigerant circulated per minute; 3. Theoretical piston displacement per minute ; 4. Power required to run the com pressor; 5. Heat removed in through condenser ; and 6. Bore and stroke of the compressor. I want the solution on a piece of paper and using the diagram الأصدقاء المقربون
I need help on the following question: The vapour compression cycle (picture provided), utilises the refrigerant R134a flowing at 0.05 kg s-1. Assuming that the compression is adiabatic and reversible. If the actual input power to the compressor is 2 kW, then: 1. You need to determine the theoretical input power to the compressor and the heat transfer (Φ) to theevaporator. Take the enthalpies h1, h2, and h3 to be 238.41, 263.68 and 81.5 kJ kg-1 (use the 'NH3 Refrigeration Table' where you can find online). 2. You need to determine the coefficient of performance based on your answer to the previous question (1). 3. You need to determine the compressors mechanical efficiency.
SUBJECT: THERMODYNAMIC COURSE: II ASSI.LACTURE: NATIQ ABBAS Example 2:- Refrigerant-134a enters the compressor of a refrigerator as superheated vapor at 0.14 MPa and -10°C at a rate of 0.05 kg/s and leaves at 0.8 MPa and 50°C. The refrigerant is cooled in the condenser to 26°C and 0.72 MPa and is throttled to 0.15 MPa. Disregarding any heat trans fer and pressure drops in the connecting lines between the components; determine (a) the rate of heat removal from the refrigerated space and the power input to the compressor, and (b) the coefficient of performance of the refrigerator. Solution: - P 0.14 MPa T=-10 C dut 246.36 kJ/kg OF P 0.8 MPa h2 = 286.69 kJ/kg P 0.72 MPa T= 26 C h3 = 87.83 kJ/kg h3 = h = 87.83 KJ/kg h4 = h3 (throttling) h4 87.83 kJ/kg 0.8 MPa 0.72 MPa/ 26 C 0.15 MPa 0.14 MPa -10°C SUBJECT: THERMODYNAMIC COURSE: II ASSI.LACTURE: NATIQ ABBAS SAMARRA RING
SUBJECT: THERMODYNAMIC COURSE: II ASSI.LACTURE: NATIQ ABBAS Example 2:- Refrigerant-134a enters the compressor of a refrigerator as superheated vapor at 0.14 MPa and -10°C at a rate of 0.05 kg/s and leaves at 0.8 MPa and 50°C. The refrigerant is cooled in the condenser to 26°C and 0.72 MPa and is throttled to 0.15 MPa. Disregarding any heat trans fer and pressure drops in the connecting lines between the components; determine (a) the rate of heat removal from the refrigerated space and the power input to the compressor, and (b) the coefficient of performance of the refrigerator. Solution: - P 0.14 MPa T=-10 C 212 h 246.36 kJ/kg da OF SAMARRA P 0.8 MPa VER h2 = 286.69 kJ/kg O P 0.72 MPa T= 26 C hg = 87.83 kJ/kg h3 =h = 87.83 KJ/kg h4 = h3 (throttling) h4 87.83 kJ/kg 0.8 MPa 50°C 0.72 MPa/ 26 C 0.15 MPa 0.14 MPa -10°C SUBIECT: THERMODYNAMIC COURSE: II ASSI.LACTURE: NATIQ ABBAS RING