Solution Found!
An air-conditioning system is shown in Fig. P4.75 in which
Chapter 4, Problem 4.75(choose chapter or problem)
An air-conditioning system is shown in Fig. P4.75 in which air flows over tubes carrying Refrigerant 134a. Air enters with a volumetric flow rate of \(50 \mathrm{~m}^{3} / \mathrm{min} \text { at } 32^{\circ} \mathrm{C}\), 1 bar, and exits at \(22^{\circ} \mathrm{C}\), 0.95 bar. Refrigerant enters the tubes at 5 bar with a quality of 20% and exits at 5 bar, \(20^{\circ} \mathrm{C}\). Ignoring heat transfer at the outer surface of the air conditioner, and neglecting kinetic and potential energy effects, determine at steady state
(a) the mass flow rate of the refrigerant, in kg/min.
(b) the rate of heat transfer, in kJ/min, between the air and refrigerant.
Questions & Answers
QUESTION:
An air-conditioning system is shown in Fig. P4.75 in which air flows over tubes carrying Refrigerant 134a. Air enters with a volumetric flow rate of \(50 \mathrm{~m}^{3} / \mathrm{min} \text { at } 32^{\circ} \mathrm{C}\), 1 bar, and exits at \(22^{\circ} \mathrm{C}\), 0.95 bar. Refrigerant enters the tubes at 5 bar with a quality of 20% and exits at 5 bar, \(20^{\circ} \mathrm{C}\). Ignoring heat transfer at the outer surface of the air conditioner, and neglecting kinetic and potential energy effects, determine at steady state
(a) the mass flow rate of the refrigerant, in kg/min.
(b) the rate of heat transfer, in kJ/min, between the air and refrigerant.
Step 1 of 5
The following are given from the question.
Inlet pressure of air, \(p_{1}=1 \mathrm{bar}\)
Inlet temperature of air, \(T_{1}=32^{\circ} \mathrm{C}=305 \mathrm{~K}\)
Exit pressure of air, \(p_{2}=0.95 \mathrm{bar}\)
Exit temperature of air, \(T_{2}=22^{\circ} \mathrm{C}=295 \mathrm{~K}\)
Inlet refrigerant pressure, \(p_{3}=5 \text { bar }\)
Quality, \(x_{3}=20 \%\)
Output refrigerant pressure, \(p_{4}=5 \text { bar }\)
Exit refrigerant temperature, \(T_{4}=20^{\circ} \mathrm{C}\)
Volumetric flow, \(A_{1} V_{1}=50 \mathrm{~m}^{3} / \mathrm{min}\)