Refrigerant 134a is the working fluid in an air? conditioning system used to maintain a room at 24°C with heat rejection to the outdoors where the temperature is 35°C. The room experiences a heat gain from the walls and windows at a rate of 275 kJ/min while the room experiences heat of 800 W from the computer, TV and lights. The refrigerant enters the compressor at 500 kPa as a saturated vapour at a rate of 100 L/min and leaves at 1.2 MPa and 50°C. Calculate (a) the actual COP; and (b) the maximum COP.