22.21 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. crossflow, both fluids unmixed b. shell-and-tube with two tube passes and one shell pass SS 22.2 An oil having a specific heat of 1880J/kgK enters a single-pass counterflow heat exchanger at a rate of 2kg/s and a temperature of 400K. It is to be cooled to 350K. Water is available to cool the oil at a rate of 2kg/s and a temperature of 280K. Determine the surface area required if the overall heattransfer coefficient is 230W/m2K