Repeat Prob. 11–72 for a mass flow rate of 3 kg/s for water.

Data from problem 72

A shell-and-tube heat exchanger with 2-shell passes and 12-tube passes is used to heat water (c_p = 4180 J/kg · K) in the tubes from 20°C to 70°C at a rate of 4.5 kg/s. Heat is supplied by hot oil (c_p = 2300 J/kg · K) that enters the shell side at 170°C at a rate of 10 kg/s. For a tube-side overall heat transfer coefficient of 350 W/m² · K, determine the heat transfer surface area on the tube side.