=+13-12. A parallel-flow air washer is to be used as an evaporative cooler. Air will enter at 100 F (38 C)

dry bulb and 62 F (17 C) wet bulb and leave at 75 F (24 C) dry bulb. Other operating condi-

tions are as follows:

(n =80 F(27C)

G _= 1000 1bm/(hr-ft2) [1.36 kg/(m2-s)]

he = 700 Btu/(hr-ftª-F) [13 kW/(m3-C)]

Q, = 4000 ft3/min (1.9 m3/s)

h_@ = 55 Btu/(hr-ft3-F) [1 kW/(m3-C)]

Gc//G _= 0.7 Btu/(Ibm-F) [2.93 kJ/(kg-C)]

vDetermine the final state of the air, and the chamber cross-sectional area and length.