4.30 Refrigerant 134a enters a heat exchanger operating ai steady state as a superheated vapour at 10 bars. 60°C, where it is cooled and condensed to saturated liquid at 10 bars. The mass flow rate of the refrigerant is 10 kg/min. A separate stream of air enters the heat exchanger at 37°C with a mass flow rate of 80 kg/min. Ignoring heat transfer from the outside of the heat exchanger and neglecting kinetic and potential energy effects, determine the exit air temperature, in C.

A rigid tank whose volume is 0.5 m³, initially containing ammonia at 20°C, 1.5 bar, is connected by a valve to a large supply line carrying ammonia at 12 bar, 130°C. The valve is opened only as long as required to fill the tank with additional ammonia, bringing the total mass of ammonia in the tank to 136.7 kg. Finally, the tank holds a two-phase liquid-vapor mixture at 20°C. Determine the heat transfer to the ammonia in the tank from the surroundings, in kJ, ignoring kinetic and potential energy effects. lev = eTextbook and Media Hint ! kJ.

As shown in the figure, Refrigerant 22 enters the compressor of an air conditioning unit operating at steady state at 40°F, 80 lb;/in? and is compressed to 160°F, 200 Ib;/in?. The refrigerant exiting the compressor enters a condenser where energy transfer to air as a separate stream occurs, and the refrigerant exits as a liquid at 200 Ib:/in?, 90°F. Air enters the condenser at 70°F, 14.7 lb:/in? with a volumetric flow rate of 750 ft/min and exits at 110°F. Neglect stray heat transfer and kinetic and potential energy effects, and assume ideal gas behavior for the air. Condenser Air at T P4=14.7 1bf'in.? (AV), 5 4 wwww T I; =110°F 3 p2 = p3 = 200 ib/in = 60°F T,= 160°F P2= 200 lbfin. T3- 90'F P=200 Ibf/in2 T3 = 90°F pi = 80 lbrin? T1 Compressor = 40°F 1+ R22 at Iz = 40°F Pi - 80 Ibf/in.? Determine the mass flow rate of refrigerant, in Ib/min, and the compressor power, in horsepower.

A rigid tank whose volume is 0.5 m³, initially containing ammonia at 20°C, 1.5 bar, is connected by a valve to a large supply line carrying ammonia at 12 bar, 200°C. The valve is opened only as long as required to fill the tank with additional ammonia, bringing the total mass of ammonia in the tank to 143.4 kg. Finally, the tank holds a two-phase liquid-vapor mixture at 20°C. Determine the heat transfer to the ammonia in the tank from the surroundings, in kJ, ignoring kinetic and potential energy effects. Qey = i 181532.33 kJ