How would you formulate this problem to obtain a more meaningful result which desired to cool a gas has [Cp = 0.35 Btu/(Ib)(F)] from 190 to 95F, using cooling water at 83F. Water costs $0.30/1100 f', and the annual fixed charges for the exchanger are $0.60/ft of inside surface, with a diameter of 0.0775 ft. The heat transfer coefficient is U = 8 Btu/(h)(ft)(F) for a gas rate of 2900 Ib/hr. Plot the annual cost of cooling water and fixed charges for the exchanger as a function of the outlet water temperature. What is the minimum total cost?