A large refrigeration plant is to be maintained at -18 ?C, and it requires refrigeration at...
A large refrigeration plant is to be maintained at -18 ?C, and it requires refrigeration at a rate of 210.0 kW . The condenser of the plant is to be cooled by liquid water, which experiences a temperature rise of 8 ?C as it flows over the coils of the condenser. Assume the plant operates on the ideal vapor-compression cycle using R-134a as the working fluid between the pressure limits of 120 kPa and 700 kPa.
a) Determine the mass flow rate (m?) of the refrigerant.
b) Determine the power input (W?net) to the compressor.
c) Determine the mass flow rate (m?) of cooling water.
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A large refrigeration plant is to be maintained at -18 ?C, and
it requires refrigeration at...
EXAMPLE 6 A household refrigeration system works with a vapor compression refrigeration system with two evaporators...
EXAMPLE 6 A household refrigeration system works with a vapor compression refrigeration system with two evaporators using Refrigerant 134a as the working fluid. This arrangement is used to achieve refrigeration at two different temperatures with a single compressor and a single condenser. The low temperature evaporator operates at -18°C with saturated vapor at its exit and has a refrigerating capacity of 10.5 kW (3 tons). The higher- temperature evaporator produces saturated vapor at 3.2 bar at its exit and has...
Thermodynamics. No interpolation needed. Problem #3. Refrigerant 134a is the working fluid for vapor-compression refrigeration cycle....
Thermodynamics. No interpolation needed.
Problem #3. Refrigerant 134a is the working fluid for vapor-compression refrigeration cycle. The evaporator temperature is 8°C and the condenser pressure is 12 bar. Saturated vapor enters the compressor and superheated vapor enters the condenser at 60°C and exits the condenser as saturated liquid. For a refrigeration capacity of 8 tons or 2.816 x104 J/s determine the following: (1) The refrigerant mass flow rate in kg/s; (2) The compressor isentropic efficiency [Hint: Interpolation is required); (3)...
A vapor-compression heat pump system uses Refrigerant R-134a as the working fluid. The refrigerant enters the...
A vapor-compression heat pump system uses Refrigerant R-134a as the working fluid. The refrigerant enters the compressor at 2.0bar, -5degC and with a mass-flow rate of 26g/s. Compression is adiabatic to 11.6bar, 60degC and the refrigerant exits the condenser 8degC sub-cooled. a) Draw a P-h chart to visualise the refrigeration cycle and display known data. b) Determine the power input to the compressor in kW c) Determine the heating capacity of the system in kW d) Determine the coefficient of...
Q3. A water chiller (refrigeration plant) uses a flooded evaporator in which the liquid refrigera...
Q3. A water chiller (refrigeration plant) uses a flooded evaporator in which the liquid refrigerant flows through the shell and the water flows within the tubes inside the shell. The flow rate of refrigerant is controlled so that the tubes are always covered with liquid refrigerant. The refrigerant used is 134a (tetrafluoroethane). It enters the evaporator at -13°C. The tubes are maintained at a temperature of 5°C by the water being cooled. The total area of the coil within the...
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...
The coefficient of performance-of vapor-compression refrigeration cycles
a) The coefficient of performance-of vapor-compression refrigeration cycles improves when the refrigerant is subcooled before it enters the throttling valve Can the refrigerant be subcooled indefinitely to maximize this effect, or is there a lower limit? Explain brieflyb) A two-stage compression refrigeration system with a flash chamber is used to produce chilled water for a commercial building The refrigeration system operates between a pressure limits of 1 2 MPa and 200 kPa with refrigerant-134a as the working fluid. The refrigerant leaves...
An ideal vapor-compression refrigeration cycle operates at steady state with Refrigerant 134a as the working fluid....
An ideal vapor-compression refrigeration cycle operates at steady state with Refrigerant 134a as the working fluid. Saturated vapor enters the compressor at 1.25 bar, and saturated liquid exits the condenser at 5 bar. The mass flow rate of refrigerant is 8.5 kg/min. A. Determine the magnitude of the compressor power input required, in kW (report as a positive number). B. Determine the refrigerating capacity, in tons. C. Determine the coefficient of performance. Please answer all parts of the question. Thanks!
In a refrigeration cycle showed in the figure below, refrigerant 134 was used as the working...
In a refrigeration cycle showed in the figure below, refrigerant 134 was used as the working fluid to remove 1. heat from the cooling chamber (condenser). The refrigerant was flowing through a pipe having inside diameter 11mm during the whole cycle. Just after expansion, the refrigerant was found to be a mixture of liquid and vapor in which liquid is found to be 60%. The mixture was flowing with a velocity of 164 ft/sec at pressure of 0.2 Mpa. Calculate...
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;...
EXAMPLE 6 A household refrigeration system works with a vapor compression refrigeration system with two evaporators using Refrigerant 134a as the working fluid. This arrangement is used to achieve refrigeration at two different temperatures with a single compressor and a single condenser. The low temperature evaporator operates at -18°C with saturated vapor at its exit and has a refrigerating capacity of 10.5 kW (3 tons). The higher- temperature evaporator produces saturated vapor at 3.2 bar at its exit and has...
Thermodynamics. No interpolation needed.
Problem #3. Refrigerant 134a is the working fluid for vapor-compression refrigeration cycle. The evaporator temperature is 8°C and the condenser pressure is 12 bar. Saturated vapor enters the compressor and superheated vapor enters the condenser at 60°C and exits the condenser as saturated liquid. For a refrigeration capacity of 8 tons or 2.816 x104 J/s determine the following: (1) The refrigerant mass flow rate in kg/s; (2) The compressor isentropic efficiency [Hint: Interpolation is required); (3)...
Q3. A water chiller (refrigeration plant) uses a flooded evaporator in which the liquid refrigerant flows through the shell and the water flows within the tubes inside the shell. The flow rate of refrigerant is controlled so that the tubes are always covered with liquid refrigerant. The refrigerant used is 134a (tetrafluoroethane). It enters the evaporator at -13°C. The tubes are maintained at a temperature of 5°C by the water being cooled. The total area of the coil within the...
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...
In a refrigeration cycle showed in the figure below, refrigerant 134 was used as the working fluid to remove 1. heat from the cooling chamber (condenser). The refrigerant was flowing through a pipe having inside diameter 11mm during the whole cycle. Just after expansion, the refrigerant was found to be a mixture of liquid and vapor in which liquid is found to be 60%. The mixture was flowing with a velocity of 164 ft/sec at pressure of 0.2 Mpa. Calculate...
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