Water flowing at a rate of 3.8 kg/s is heated from 38 to 55 C in the tubes of a shell and tube heat exchanger. The shell side is one pass with water flowing at 1.9 kg/s entering at 94 C. The overall heat transfer coefficient is 1420 W/m^2*K. The average water velocity in the 1.905 cm ID tubes is 0.366 m/s. Because of space limitations the tubes may not exceed 2.44 m in length. Determine:
a) the required number of tube passes
b) the number of tubes per pass
c) the length of the tubes (per pass) keeping in mind the space restriction.