Homework Question 9:

4.71 Separate streams of air and water flow through the compressor and heat exchanger

arrangement shown in Fig. P4.71. Steady-state operating data are provided on the figure. Heat

transfer with the surroundings can be neglected, as can all kinetic and potential energy effects.

The air is modeled as an ideal gas. Determine

a. the total power required by both compressors, in kW.

b. the mass flow rate of the water, in kg/s.

Air

P₁ = 1 bar

. T₁ = 300 K

m₁ = 0.6 kg/s

Compressor A

P₂=3 bar +2

T₂=600 K

T6 =30°C

P6 Ps

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P4=9 bar

T₁=800 K4

FIGURE P 4.71

Compressor B

3+ P3=P₂

T3=450 K

-Heat exchanger

Water

T5 = 20°C

Ps= 1 bar

WCVB