Solve Problem 5.20 for a cross flow heat exchanger where the magnesium chloride solution flow is mixed and the hexane flow is unmixed.

Problem 5.20

A counter flow heat exchanger is utilizing a cold 20% magnesium chloride solution to cool a flow of hexane. The hexane enters the heat exchanger at 26°C and the magnesium chloride solution enters at 0°C. The volumetric flow rates of the hexane and magnesium chloride solution are 30 L/s and 26 L/s, respectively. The heat exchanger has an overall heat transfer coefficient of 1,280 W/m2-K. The required heat transfer rate between the fluids is 700 kW.