You are reevaluating the pump choice that was made last year by your boss. the expected cost savings have not occurred because the pump is too small. choice a, at $90,000, is to replace the pump with one that is the right size and sell the old one. choice b , at $100,000, is to buy a small pump to use in tan- dem with the existing pump. the two-pump solution has slightly higher maintenance costs, but it is more flexible and reliable. what criteria should you use? which choice would you recommend, and why?

Along 8-cm diameter steam pipe whose external surface temperature is 900c connects two buildings. the pipe is exposed to ambient air at 70c with a wind speed of 50 km/hr blowing across the pipe. determine the heat loss from the pipe per unit length. (b) air at 500c enters a section of a rectangular duct (15 cm x 20 cm) at an average velocity of 7 m/s. if the walls of the duct are maintained at 100c. a) the length of the tube for an exit temperature of the air to be 40 0c. b)the rate of heat transfer from the air. c) the fan power needed to overcome the pressure drop in this section of the duct.