Answer Happy

Water is used in both the hot and cold stream of a counter flow, concentric tube heat exchanger. The hot stream flows through the inside tube, of diameter 22mm, and has an inlet and outlet temperature of 80°C and 70°C, respectively, flowing at a rate of 24 litres per minute. The cold stream enters the outer tube of the exchanger at a temperature of 20°C at a rate of 12 litres per minute. The overall heat transfer coefficient of the heat exchanger is 1200 W m-²K-1. a) Sketch on a single set of axes a graph of the temperature against distance along the heat exchanger for both the hot and cold stream. b) Determine the amount of heat being exchanged between the hot and cold stream and the exit temperature of the cold stream. c) Determine the log mean temperature difference for this heat exchanger.