Problem 2 (40 Points - Comparing parallel and counter flow HXs) A counterflow

double-pipe heat exchanger is used to heat water from 20°C to 80°C at a rate of 1.2 kg/s. The

heating is to be completed by geothermal water available at 160°C at a mass flow rate of 2 kg/s.

The inner tube is thin-walled and has a diameter of 1.5 cm. If the overall heat transfer coefficient

of the heat exchanger is 640 W/m²K, determine the length of the heat exchanger required to

achieve the required heating. Repeat the calculations assuming a parallel flow configuration,

sketch the temperature variation in the HXs, and briefly discuss your results.