If the overall heat-transfer coefficient, initial fluid temperature, and total heat-transfer area determined in Problem 22.2 remain the same, find the exit oil temperature if the configuration is changed to
a. Cross flow, both fluids unmixed
b. shell-and-tube with two tube passes and one shell pass

Data From Problem 22.2

A water-to-oil heat exchanger has entering and exiting temperatures of 255 and 340 K, respectively, for the water and 305 and 350 K, respectively, for the oil. What is the effectiveness of this heat exchanger?