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…
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
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
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
3.) An ammonia compressor operates at evaporator pressure of 316.02 kPa and a condenser pressure of 1557 kPa. A twin-cylinder compressor with bore to stroke ratio of 0.85 is to used at 1200 rpm. The actual volumetric efficiency is 92% and compression and mechanical efficiency is 78% and 80% respectively. For a cooling capacity of 25 TR, (a) the sketch the p-h diagram labeling the evaporating and condensing temperature and pressures (b) define the all properties of ammonia taken from saturation table. Determine (c) the quantity of cooling water in the condenser in kg/min if the increase in temperature is 8°C, (d) the bore and stroke expressed in cm and (e) the size of the driving motor in hp. Given: h2 = h at 1557 kPa and s2 = s1 1695 kJ/kg
A vapour-compression refrigeration system operates with Refrigerant 134 with two evaporators with varying cooling capacity. The low temperature evaporator (#1) operates at -20°C with saturated vapour at its exit and has a refrigeration capacity of 3 tons. The higher temperature evaporator (#2) produces saturated vapour at 3.6 bar at its exit and has a refrigerating capacity of 2 tons. Compression is isentropic to the condenser pressure of 12 bar. There are no pressure drops in the flow through the condenser and the two evaporators and the refrigerant leaves the condenser as saturated liquid at 12 bar. Determine: The mass flow rate of the refrigerant in kg/s through each evaporators;The power input for the compressor, in kW;The coefficient of performance of this refrigeration system;The heat transfer through the condenser in kW;The rates of exergy destruction in each expansion valves in kW for T0 = 300K;Draw the T-s diagram of this system.
A refrigeration system is to be used to cool 45,000kg water for 32 Celsius to 19 Celsius in 5 hours. The refrigerant is R-134A and the operating condition are evaporating pressure 810 kPa and 1800 kPa liquefication pressure. Determine COP, quantity of cooling water in the condenser for an increase in temperature of 7 Celsius compressor power, volume of flow rate entering the compressor. With schematic diagram. Using this table https://www.docdroid.net/VkxK8WH/refrigerant-134a-pdf
! Required information Problem 08.048 - DEPENDENT MULTI-PART PROBLEM - ASSIGN ALL PARTS - Piston Device with Refrigerant NOTE: This is a multi-part question. Once an answer is submitted, you will be unable to return to this part. A piston-cylinder device initially contains 2 kg of refrigerant-134a at 100 kPa and 20°C. Heat is now transferred to the refrigerant from a source at 150°C, and the piston, which is resting on a set of stops, starts moving when the pressure inside reaches 120 kPa. Heat transfer continues until the temperature reaches 80°C. Assume the surroundings to be at 25°C and 100 kPa. R-134a 100 kPa 20°C 150°C Problem 08.048.d - Efficiency of Piston Device with Refrigerant Determine the second-law efficiency of this process. The second-law efficiency of this process is %.