The exhaust-gas temperature leaving a continuously operating furnace is 260 c, and a proposal is being considered to install a heat exchanger in the exhaust-gas stream to generate low-pressure steam at 105 c. the question to be investigated is whether it is economical to install such a heat exchanger, and, if so, to find its optimum size. the following data apply: flow of exhaust gas, 7.5 kg/s. specific heat of exhaust gas, 1.05 kj/(kg k). value of the heat in the form of steam, $1.50 per gigajoule. u value of heat exchanger based on gas-side area, 23 w/(m2 k). cost of the heat exchanger including installation based on gas-side area, $90 per square meter. interest rate, 8 percent. life of installation, 5 years. saturated liquid water enters heat exchanger at 105 c and leaves as saturated vapor. (a) develop the equation for the savings as a function of the area, expressed as a uniform annual amount.(b) what is the maximum permitted area if the exit-gas temperature is to be above 120 c in order to prevent condensation of water vapor from the exhaust gas? (c) use a seven-point fibonacci search and set up a table to simplify calculation of the optimum heat-transfer area.