1.2. The ideal vapor- compression Refrigeration cycle
Many of the impracticalities related with the reversed Carnot cycle can be removed by vaporizing the refrigerant completely before it is compressed and by replacing the turbine with a throttling devices, such as an expansion valve or capillary tube, The cycle that results is called the ideal vapor compression refrigeration cycle, and is shown schematically and on T-s diagram in Fig 1.2. The vapor-compression refrigeration cycle is the most broadly used cycle for refrigerators, air conditioning systems, and heat pumps. It consists of four processes:
Process 1-2 Isentropic compression in a compressor.
Process 2-3 Constant- pressure heat rejection in a condenser.
Process 3-4 Throttling in an expansion device.
Process 4-1 Constant –pressure heat absorption in an evaporator.
In the ideal vapour-compression refrigeration cycle, the refrigerant enters as a saturated vapor to the compressor at state 1 and is compressed isentropically to the condenser pressure at state 2. During this isentropic compression process the temperature of the refrigerant increases to the temperature which is well above that of the …show more content…
To make it a more realistic model for the actual vapour-compression refrigeration cycle this (throttling) process is maintained in the cycle. If the throttling device is replaced by the isentropic turbine, then the refrigerant would enter the evaporator at state 4¹ instead of state 4. As a result, the net work input would reduce (by the amount of work output of the turbine) and the refrigeration capacity would increase (by the area under process curve 4¹- 4 in Fig 1.2). If the expansion valve is replaced by a turbine, it is not a realistic, however, since the added cost and complexity cannot justify by the added
Many of the impracticalities related with the reversed Carnot cycle can be removed by vaporizing the refrigerant completely before it is compressed and by replacing the turbine with a throttling devices, such as an expansion valve or capillary tube, The cycle that results is called the ideal vapor compression refrigeration cycle, and is shown schematically and on T-s diagram in Fig 1.2. The vapor-compression refrigeration cycle is the most broadly used cycle for refrigerators, air conditioning systems, and heat pumps. It consists of four processes:
Process 1-2 Isentropic compression in a compressor.
Process 2-3 Constant- pressure heat rejection in a condenser.
Process 3-4 Throttling in an expansion device.
Process 4-1 Constant –pressure heat absorption in an evaporator.
In the ideal vapour-compression refrigeration cycle, the refrigerant enters as a saturated vapor to the compressor at state 1 and is compressed isentropically to the condenser pressure at state 2. During this isentropic compression process the temperature of the refrigerant increases to the temperature which is well above that of the …show more content…
To make it a more realistic model for the actual vapour-compression refrigeration cycle this (throttling) process is maintained in the cycle. If the throttling device is replaced by the isentropic turbine, then the refrigerant would enter the evaporator at state 4¹ instead of state 4. As a result, the net work input would reduce (by the amount of work output of the turbine) and the refrigeration capacity would increase (by the area under process curve 4¹- 4 in Fig 1.2). If the expansion valve is replaced by a turbine, it is not a realistic, however, since the added cost and complexity cannot justify by the added