Pressure limits in a two-stage cooling system are 0.9 MPa and
250kPa. Refrigerant condenser
comes out as saturated liquid and works at 700kPa pressure
reduced to the pressure of the evaporation chamber. Meanwhile, some
of the refrigerant evaporates and is mixed with the fluid from the
low pressure compressor. The mixture is then
It is compressed to condenser pressure with high pressure
compressor. The liquid in the evaporation chamber is reduced to
evaporator pressure and draws heat from the cooled environment as
it passes through the evaporator. Refrigerant flow rate in the low
pressure compressor is 0.18 kg / s. Since the refrigerant from the
evaporator is saturated steam and the isentropic efficiency of both
compressors is 85%,
a) Calculate the refrigerant flow rate in the high pressure
compressor
b) Calculate the heat drawn from the cooled environment
c) Calculate the COP value of the cooling system
d) Mass flow, compressor efficiency and heat drawn by a
single-stage cycle with the same pressure limits.
and calculate the COP value.
Pressure limits in a two-stage cooling system are 0.9 MPa and 250kPa. Refrigerant condenser comes out...
Pressure limits in a two-stage cooling system are 0.9 MPa and
250kPa. Refrigerant condenser
comes out as saturated liquid and works at 700kPa pressure
reduced to the pressure of the evaporation chamber. Meanwhile, some
of the refrigerant evaporates and is mixed with the fluid from the
low pressure compressor. The mixture is then
It is compressed to condenser pressure with high pressure
compressor. The liquid in the evaporation chamber is reduced to
evaporator pressure and draws heat from the cooled...
A two-stage cascade refrigeration system operates between the pressure limits of 1.4MPa and 200 kPa with refrigerant-134a. The fluid leaves the condenser as a saturated liquid and is throttled to a flash chamber operating at 0.50 MPa. Part of the refrigerant evaporates in the flashing process, and this vapor is mixed with the refrigerant leaving the low-pressurin compressor. The liguid in the flash chamber iS throttled to the evaporator pressure and cools the refrigerated space. The mass flow rate 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...
A refrigeration system with a flash chamber operates with R134a between the pressure limits of 1.0 and 0.1 MPa. The refrigerant leaves the condenser as saturated liquid and is throttled to a flash chamber operating at 0.5 MPa. The refrigerant leaving the low-pressure compressor at 0.5 MPa is also routed to the flash chamber. The vapor in the flash chamber is then compressed to the condenser pressure by the high-pressure compressor, and the liquidis throttled to the evaporator pressure. Assume...
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 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...
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...
(100 points) Figure below shows the schematic diagram of a two-stage cascade refrigeration system (also called the Economizer 2-Stage Refrigeration Cycle). Comparing to the cascade two-stage refrigeration system discussed in In-class Activity #10a, in this case, the flash chamber (now called Flash Intercooler) is still used but the mixing chamber is removed. The superheated vapor (2) out of the low-pressure compressor (1) is routed into the flash chamber, and the saturated vapor (3) out of the flash chamber enters directly...
5/An ammonia refrigeration system consists of two stages compressors, two cvaporators, flash intereooler and sub-cooler, heat exchanger and condenser. Ammonia vapor condenses in the condenser at 40 "C. The amount of liquid refrigerant goes to the low temperature evaporator is sub-cooled 10 °C in the liquid sub- cooler and another 10 °C in the liquid-vapor heat exchanger. Vapor leaves the low pressure evaporator saturated at -30 °C, and then it is superheated in the heat exchanger at the same pressure....
determine 1) sub cooling achieved in the heat
exchanger, 2) refrigerant flow rate, 3) cop of the plant
ii) A refrigeration unit with 100-ton capacity operates in a vapour compression O refrigeration cycle between the temperature limits of 308 and 263 K. It uses R-12 G as a refrigerantC A heat exchanger is inducted in the circuit in between the condenser and the expander, The refrigerant vapour leaving the evaporator is superheated in the heat exchanger in the countercurrent flow...