12. A refrigerator uses refrigerant-134a as the working fluid and operates on a mechanical vapor-compression cycle between evaporator pressure of 0.14 MPa and condenser pressure of 0.8 MPa. At the evaporator exit, the refrigerant is dry saturated vapor, and it becomes saturated liquid at the condenser exit. If the mass flow rate of the refrigerant is 0.05 kg/s, determine with the aid of either R-134a table or R-134a chart: (a) The rate of heat removal from the evaporator (refrigeration effect). (b) The power input to the compressor. (c) (d) The rate of heat rejection from the condenser to the environment. The CoP of the refrigerator. Also, sketch the cycle on a P-h diagram. [Ans: (a) 7.13 kW; (b) 1.8 kW; (c) 8.93 kW; (d) 3.96]