Question 1 (20 marks) a) Consider a shell-and-tube heat exchanger with 2-shell pass and 14-tube passes used to heat water in the tubes with geothermal steam condensing at 120 °C on the shell side. The tubes are thin-walled and have a diameter of 2.2 cm and length of 3.4 m per pass. Water enters the tubes at 20 °C with a rate of 3.9 kg/s. The temperature difference between the two fluids at the exit is 46 °C. Determine: 1) The rate of heat transfer 2) The rate of condensation of steam 3) The overall heat transfer coefficient Extracts from saturated steam tables are given below (Table 1). (3 marks) (3 marks) (2 marks) b) A long homogeneous resistance wire of radius ro = 5 mm is being used to heat the air in a room by the passage of electric current. Heat is generated in the wire uniformly at a rate of g-5 x 10' W/m2 as a result of resistance heating. If the temperature of the outer surface of the wire remains at 180°C. Take the thermal conductivity of the wire to be k = 8 W/m . °C. Determine: 1) The temperature at r-2 mm after steady operation conditions are reached. (12 marks)