2. MULTIPLE EVAPORATOR/ EXPANSION VALVE A refrigeration installation using Freon 12, comprises one compressor, one condenser...
Q1/ Figure 1 shows a refrigeration system of multi evaporators and single compressor using R407C as refrigerant. The evaporators provide cooling capacity of 10 and 20 TR at temperatures of -10 °C and 10 °C respectively. The system provided with multi ex valves (the multi expansion valve advantage is that the refrigerant that enters the low temperature evaporator expansion valve is saturated liquid and the flash gas is removed at poirnt 4). The condenser temperature is 50 °C. Calculate the...
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...
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....
A simple refrigerator comprises an evaporator, compressor, condenser and throttle valve (refer Figure 1 below). The refrigerant used, R12, leaves the evaporator at 1.0 bar as a saturated vapour. The vapour is compressed to 7.0 bar, then passes through a condenser where the refrigerant is condensed to form a saturated liquid. The fluid is then throttled to 1.0 bar and re-enters the evaporator. Assume the compressor efficiency is 80% Determine: i) The temperature of the fluids at points 1, 2,...
ycles 1. A refrigeration system operates with a superheated cycle using R134a. The required refrigerating capacity is 30 TR. The evaporator works at -10 Cand the condenser pressure is 1 MPa. The refrigerant is superheated by 10°C before entering to the compressor. Assume isentropic compression in the compressor and isenthalpic expansion in the expansion valve. Answering the following questions using the ph diagram. and the c Sion in the ring to a) Sketch the process in the p-h diagram and...
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...
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...
In a vapor-compression refrigeration cycle, ammonia exits the
evaporator as saturated vapor at -22 °C. There are
irreversibilities in the compressor. The refrigerant enters the
condenser at 16 bar and 160 °C, and saturated liquid exits at 16
bar. There is no significant heat transfer between the compressor
and its surroundings, and the refrigerant passes through the
evaporator with a negligible change in pressure.
Calculate the coefficient of performance, b, and the isentropic
compressor efficiency, defined as:
2s Condenser Expansion...
In a vapor-compression refrigeration cycle, ammonia exits the evaporator as saturated vapor at -22°C. The refrigerant enters the condenser at 16 bar and 160°C, and saturated liquid exits at 16 bar. There is no significant heat transfer between the compressor and its surroundings, and the refrigerant passes through the evaporator with a negligible change in pressure. If the refrigerating capacity is 150 kW, determine: (a) the mass flow rate of the refrigerant, in kg/s. (b) the power input to the...