Two heat exchangers in a circulating water loop transfer heat from a fluid condensing at 175F...

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Two heat exchangers in a circulating water loop transfer heat from a fluid condensing at 175°F to a boiling fluid at 68°F, as shown in Figure P6.14. The overall heat transfer coefficients of the evaporator and condenser are UE = 5.3 Btu/h ft2.°F and Uc = 7 Btu/h-ft2.°F, respectively. The first cost of the heat exchangers is $21.50/ft², and the present worth of the lifetime pumping costs is 11.75[$.h/lbm]m. This system must accomplish a heat transfer rate of 220,000 Btu/h between the condensing and boiling fluids. Using a numerical optimization algorithm, determine the heat exchanger areas, A, and A₂, that minimize the total present worth of costs. Condensing fluid T = 175°F Condenser Uc=7 Btu/h-ft2.°F ww www T = 175°F FIGURE P6.14 Water 1 2 O Tb = 68°F www www Evaporator UE = 5.3 Btu/h-ft².°F Boiling fluid Tb = 68°F Two heat exchangers in a circulating water loop transfer heat from a fluid condensing at 175°F to a boiling fluid at 68°F, as shown in Figure P6.14. The overall heat transfer coefficients of the evaporator and condenser are UE = 5.3 Btu/h ft2.°F and Uc = 7 Btu/h-ft2.°F, respectively. The first cost of the heat exchangers is $21.50/ft², and the present worth of the lifetime pumping costs is 11.75[$.h/lbm]m. This system must accomplish a heat transfer rate of 220,000 Btu/h between the condensing and boiling fluids. Using a numerical optimization algorithm, determine the heat exchanger areas, A, and A₂, that minimize the total present worth of costs. Condensing fluid T = 175°F Condenser Uc=7 Btu/h-ft2.°F ww www T = 175°F FIGURE P6.14 Water 1 2 O Tb = 68°F www www Evaporator UE = 5.3 Btu/h-ft².°F Boiling fluid Tb = 68°F

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To determine the necessary area for the heat exchangers in order to achieve the desired heat transfe... View the full answer