5.11 A flow of cold water enters a parallel-flow heat exchanger at 20°C and leaves at 100°C. The cold water is being heated by a hot water flow that enters the heat exchanger at 160°C and leaves at 120°C. The overall heat transfer coefficient for this heat exchanger is 325 W/m2 K. The heat exchanger must transfer heat between the water streams at a rate of 30 kW. Determine the heat exchanger area required (m2).