. Water at a flow rate of 46000 kg/h is heated in a shell and tube heat exchanger with to shell passes and eight tube passes. The total surface area of the exchanger is 925 m² . The water is initially at 75C and is heated to 160C. Gas (which may be approximated as air) enters the exchanger at 360C and leaves at 180C. What is the overall heat transfer coefficient and what is the expected flow rate of gas in the exchanger?