For the problems below (Problem 3 and on), it is not necessary to interpolate in the...
For the problems below (Problem 3 and on), it is not necessary to interpolate in the use of any tables. It is permissible to identify a point in the chart that brackets the value of interest.
A vapor-compression refrigeration cycle is conducted with HFC-134a as a refrigerant. The COP of the cycle is known to be 2.0. The inlet stream to the evaporator is a 40.% quality stream at 0.30 MPa, and the inlet stream to the compressor is saturated vapor. What is the efficiency of the compressor?
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For the problems below (Problem 3 and on), it is not necessary
to interpolate in the...
A two-stage compression refrigeration system with an adiabatic liquid-vapor separation unit uses refrigerant-134a as working fluid....
A two-stage compression refrigeration system with an adiabatic liquid-vapor separation unit uses refrigerant-134a as working fluid. The system operates the evaporator at 0.4 MPa, the condenser at 1.6 MPa, and the separator at 0.8 MPa. The compressors use 25 kW of power. Given that the refrigerant is saturated liquid at the inlet of each expansion valve and saturated vapor at the inlet of each compressor, and the compressors are isentropic: (0) show the process on a T-s diagram; ) calculate...
A two-stage compression refrigeration system with an adiabatic liquid-vapor separation unit uses refrigerant-134a as working fluid....
A two-stage compression refrigeration system with an adiabatic liquid-vapor separation unit uses refrigerant-134a as working fluid. the system operates the evaporator at 0.4Mpa, the condenser at 1.6Mpa and the separator at 0.8 Mpa. The compressors use 25kW of power. Given that the refrigerant is saturated liquid at the inlet of each compressor, and the compressors are isentropic: i) show the process on a T-s diagram, ii) calculate the rate of cooling provided by the evaporator, the COP of the heat...
A vapor compression refrigeration cycle utilizes R-134a as the working fluid. The refrigerant flow rate is 50 g/s. Vapor at 150 kPa and -10 0C enters the compressor and leaves at 1.2 MPa and 75 0C. Th...
A vapor compression refrigeration cycle utilizes R-134a as the working fluid. The refrigerant flow rate is 50 g/s. Vapor at 150 kPa and -10 0C enters the compressor and leaves at 1.2 MPa and 75 0C. The power input to the non-adiabatic compressor is measured and found to be 2.4 kW. The refrigerant enters the expansion valve at 1.15 MPa and 40 0C and leaves the evaporator at 160 kPa and -15 0C. Determine the entropy generation in the compression...
Find (a) the compressor power, in kW, (b) the refrigeration capacity, in tons, and (c) the...
Find (a) the compressor power, in kW, (b) the refrigeration capacity, in tons, and (c) the coefficient of performance (COP) for a real vapor-compression refrigeration cycle using refrigerant 134a. The refrigerant enters the compressor at a rate of 0.15 kg/s as a saturated vapor at −40 °C and leaves the condenser as a saturated liquid at 16 °C. The isentropic efficiency of the compressor is 80%.
A freezer is designed, based on vapor-compression refrigeration cycle. The designed conditions are: R-134a as refrigerant,...
A freezer is designed, based on vapor-compression refrigeration cycle. The designed conditions are: R-134a as refrigerant, with a cooling capacity of 500 kW; compressor of 70% efficiency, with a superheat of 10°C before compressor inlet; operation temperature of -10°C inside the refrigerator, with the environment temperature of 25°C outside the refrigerator; Determine the pressure range of refrigeration cycle if a 10°C difference is required to ensure effective heat transfer of evaporator and condenser; Plot the refrigeration cycle on P-h diagram;...
Problem 2 (30 pts): Consider a two-stage vapor-compression refrigeration system operating between the pressure limits of...
Problem 2 (30 pts): Consider a two-stage vapor-compression refrigeration system operating between the pressure limits of 1.5 MPa and 150 kPa with refrigerant-134a as the working fluid. The refrigerant leaves the condenser as a saturated liquid and is throttled to a flash chamber operating at 0.45 MPa. The mass flow rate of the refrigerant through the low pressure compressor is 0.15 kg/s. Assuming the refrigerant leaves the evaporator as a saturated vapor, determine (a) the mass flow rate of the...
1) A commercial refrigerator with refrigerant-134a as the working fluid is used to keep the refrigerated...
1) A commercial refrigerator with refrigerant-134a as the working fluid is used to keep the refrigerated space at -30°C by rejecting its waste heat to cooling water that enters the condenser at 16 °C at a rate of 0.25 kg/s and leaves at 26°C. The refrigerant enters the condenser at 1.2 MPa and 65°C and leaves at 42°C. The inlet state of the compressor is 60 kPa and -34°C and the compressor is estimated to gain a net heat of...
Condenser Compressor An ideal vapor-compression refrigeration cycle is modified to include a counter-flow heat exchanger as...
Condenser Compressor An ideal vapor-compression refrigeration cycle is modified to include a counter-flow heat exchanger as shown. Refrigerant 134a leaves the evaporator as saturated vapor at 0.10 MPa and is heated at constant pressure to 20°C before entering the compressor. Following isentropic compression to 1.4 MPa, the refrigerant passes through the condenser and exits at 45°C and 1.4 MPa. The liquid then passes through the heat exchanger and enters the expansion valve at 1.4 MPa. The mass flow rate of...
Please also draw the T-S diagrams and PH diagrams to facilitate understanding. Thank you. 5. The refrigeration system s...
Please also draw the T-S diagrams and PH diagrams to facilitate
understanding. Thank you.
5. The refrigeration system shown below is another variation of the basic vapor compression refrigeration system which attempts to reduce the compression work. In this system, a heat exchanger is used to superheat the vapor entering the compressor while sub-cooling the liquid exiting from the condenser Consider a system of this type that uses refrigerant-134a as its refrigerant and operates the evaporator at -10°C, and the...
NOTE: This is a multi-part question Once an answer is submitted you will be unable to return to t...
NOTE: This is a multi-part question Once an answer is submitted you will be unable to return to this part Consider a two-stage cascade refrigeration system operating between the pressure limits of 1.4 MPa and 140 kPa with refrigerant-134a as the working fluid. Heat rejection from the lower cycle to the upper cycle takes place in an adiabatic counterflow heat exchanger where the pressure in the upper and lower cycles are 0.7 and 08 MPa, respectively. In both cycles, the...
A two-stage compression refrigeration system with an adiabatic liquid-vapor separation unit uses refrigerant-134a as working fluid. The system operates the evaporator at 0.4 MPa, the condenser at 1.6 MPa, and the separator at 0.8 MPa. The compressors use 25 kW of power. Given that the refrigerant is saturated liquid at the inlet of each expansion valve and saturated vapor at the inlet of each compressor, and the compressors are isentropic: (0) show the process on a T-s diagram; ) calculate...
Problem 2 (30 pts): Consider a two-stage vapor-compression refrigeration system operating between the pressure limits of 1.5 MPa and 150 kPa with refrigerant-134a as the working fluid. The refrigerant leaves the condenser as a saturated liquid and is throttled to a flash chamber operating at 0.45 MPa. The mass flow rate of the refrigerant through the low pressure compressor is 0.15 kg/s. Assuming the refrigerant leaves the evaporator as a saturated vapor, determine (a) the mass flow rate of the...
1) A commercial refrigerator with refrigerant-134a as the working fluid is used to keep the refrigerated space at -30°C by rejecting its waste heat to cooling water that enters the condenser at 16 °C at a rate of 0.25 kg/s and leaves at 26°C. The refrigerant enters the condenser at 1.2 MPa and 65°C and leaves at 42°C. The inlet state of the compressor is 60 kPa and -34°C and the compressor is estimated to gain a net heat of...
Condenser Compressor An ideal vapor-compression refrigeration cycle is modified to include a counter-flow heat exchanger as shown. Refrigerant 134a leaves the evaporator as saturated vapor at 0.10 MPa and is heated at constant pressure to 20°C before entering the compressor. Following isentropic compression to 1.4 MPa, the refrigerant passes through the condenser and exits at 45°C and 1.4 MPa. The liquid then passes through the heat exchanger and enters the expansion valve at 1.4 MPa. The mass flow rate of...
Please also draw the T-S diagrams and PH diagrams to facilitate
understanding. Thank you.
5. The refrigeration system shown below is another variation of the basic vapor compression refrigeration system which attempts to reduce the compression work. In this system, a heat exchanger is used to superheat the vapor entering the compressor while sub-cooling the liquid exiting from the condenser Consider a system of this type that uses refrigerant-134a as its refrigerant and operates the evaporator at -10°C, and the...
NOTE: This is a multi-part question Once an answer is submitted you will be unable to return to this part Consider a two-stage cascade refrigeration system operating between the pressure limits of 1.4 MPa and 140 kPa with refrigerant-134a as the working fluid. Heat rejection from the lower cycle to the upper cycle takes place in an adiabatic counterflow heat exchanger where the pressure in the upper and lower cycles are 0.7 and 08 MPa, respectively. In both cycles, the...
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