Question

In: Mechanical Engineering

An ideal vapor compression refrigeration cycle using r134a as the refrigerant is being used to cool...

An ideal vapor compression refrigeration cycle using r134a as the refrigerant is being used to cool a house. It provides 3 refrigeration tons ≈ 10.5kW of cooling (heat removal from the house air). The refrigerant in the evaporator operates at 400kPa while in the condenser it is at 1000kPa. Treat the surroundings as a thermal reservoir at 33◦C and the air in the house as a thermal reservoir at 19◦C. All reservoirs are at 100kPa.

1. What is the COPr of this cycle?

2. How fast is exergy destroyed (kJ/s) in each process (evaporator, condenser, throttle, compressor)?

3. Which process has the lowest second law efficiency?

4. What is the rate of exergy destruction (kJ/s) for the cycle?

Solutions

Expert Solution


Related Solutions

An ideal vapor compression refrigeration cycle with R134a as the working fluid operates between the pressure...
An ideal vapor compression refrigeration cycle with R134a as the working fluid operates between the pressure limits of 200 kPa and 1200 kPa. Determine a) the mass fraction of the refrigerant that is in the liquid phase at the inlet of the evaporator, and b) the amount of heat transfer (in kJ/kg) to the refrigerant in the evaporator (??).
There is a vapor compression type refrigeration cycle using the refrigerant HFC 134 a. In the...
There is a vapor compression type refrigeration cycle using the refrigerant HFC 134 a. In the condenser, it is isostatically cooled, the condensation temperature is 50 ° C., and the condenser outlet is the compressed liquid at 45 ° C. In the evaporator, it is isothermally heated, the evaporation temperature is 10 ° C. and the outlet of the evaporator is heated steam at 15 ° C. When the expansion valve performs isenthalpic expansion, and the adiabatic efficiency of the...
An air conditioner using refrigerant-134a as the working fluid and operating on the ideal vapor-compression refrigeration...
An air conditioner using refrigerant-134a as the working fluid and operating on the ideal vapor-compression refrigeration cycle is to maintain a space at 30°C while operating its condenser at 1000 kPa. Determine the COP of the system when a temperature difference of 2°C is allowed for the transfer of heat in the evaporator. (Take the required values from saturated refrigerant-134a tables.) The COP of the system is ?
An ice-making machine operates on the ideal-vapor compression cycle using refrigerant-134a. The refrigerant enters the compressor...
An ice-making machine operates on the ideal-vapor compression cycle using refrigerant-134a. The refrigerant enters the compressor as saturated vapor at 40 psia and leaves the condenser as saturated liquid at 80 psia. Water enters the ice machine at 55°F and leaves as ice at 25°F. For an ice production rate of 21 lbm/h, determine the power input to the ice machine (169 Btu of heat needs to be removed from each lbm of water at 55°F to turn it into...
For an ideal vapor-compression heat pump cycle, refrigerant 134a is used to provide 35 kW of...
For an ideal vapor-compression heat pump cycle, refrigerant 134a is used to provide 35 kW of heat to a building. Saturated vapor enters the compressor at 1.6 bar and saturated liquid exits the condenser which operates at 8 bar. What is (a) the mass flow rate of the refrigerant, and (b) the COP?
A vapor-compression refrigeration cycle operates at steady state with Refrigerant 134a as the working fluid. Saturated...
A vapor-compression refrigeration cycle operates at steady state with Refrigerant 134a as the working fluid. Saturated vapor enters the compressor at 2 bar, and saturated liquid exits the condenser at 10 bar. The isentropic compressor efficiency is 80%. The mass flow rate of refrigerant is 7 kg/min. Determine: (a) the compressor power, in kW. (b) the refrigeration capacity, in tons. (c) the coefficient of performance.
A vapor-compression refrigeration cycle working with R22 contains a liquid-to-suction heat exchanger. The saturated liquid refrigerant...
A vapor-compression refrigeration cycle working with R22 contains a liquid-to-suction heat exchanger. The saturated liquid refrigerant at 40 °C leaving the condenser and entering the heat exchanger is used to superheat the saturated vapor refrigerant leaving the evaporator at 7 °C by 8 °C. If the compressor is capable of pumping 5 l/s of vapor refrigerant measured at the inlet to the compressor and the compression processes are considered isentropic in both cases listed below, determine; (a) The refrigerating capacity...
A single stage simple vapr compression refrigeration cycle using R12 refrigerant is operating at a condenser...
A single stage simple vapr compression refrigeration cycle using R12 refrigerant is operating at a condenser temperature of 40 degrees C and an evaporator temperature of -5 degrees C. If the compressor is a reciprocating type compressor with 4 cylinder, rotating at 1800 RPM, has a cylinder diameter of 5cm, stroke length to diameter ratio of 1.4, and clearance ratio of 5%. Assume a polytropic index to be 1.13. 1- Sketch the cycle flow diagram, and identify the states on...
Consider   a   vapour   compression   refrigeration   cycle   that   uses   R-134a   as   refrigerant.   The   R-134a   enter
Consider   a   vapour   compression   refrigeration   cycle   that   uses   R-134a   as   refrigerant.   The   R-134a   enters   the   compressor   as   a   saturated   vapour   at   200   kPa,   and   exits   the   condenser   as   a   saturated   liquid   at   900   kPa.   The   rate   of   refrigeration   of   the   cycle   is   to   be   6.0   tons   of   refrigeration   (1   ton   of   refrigeration   =   3.517   kW).   The   compressor   isentropic   efficiency   is   80%.   Determine:   a) The   temperature   of   evaporation   and   condensation   of   the   refrigerant;   b) Mass   flow   of   the   refrigerant   R-134a,   in  ...
Refrigerant R134a is entering a condenser and is being cooled by water. The refrigerant enters the...
Refrigerant R134a is entering a condenser and is being cooled by water. The refrigerant enters the condenser with a mass flow rate of 6 kg/min at 1 MPa and 70 0C and leaves at 35 0C. The cooling water enters at 300 KPa and 15 0C and leaves at 25 0C. Neglecting any pressure drop, determine: The mass flow rate of the cooling water The heat transfer rate from the refrigerant to the water. The rate of entropy production within...
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT