1. A team of students have designed a battery-powered cooler, which promises to keep beverages at a high-drinkability temperature of 36°F while outside is 100°F. If the insulation leaks heat at a rate of 100 Btu/h, calculate the minimum electrical power required, in Watts. If we use USB-charged 5 V batteries, what is the minimum battery size needed, in Amp-hours, if the cooler is supposed to work for 4 hours?

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.