2. A counter flow heat double-pipe Heat exchanger (HX) is to be heat water from 20C to 80 C at a rate of 2.4 kg/s. The heating is to be accomplished by geothermal water available at 140 C at a mass flow rate of 2 kg/s. The inner tube is thin-walled and has a diameter of 2 cm. If Overall heat transfer coefficient of the HX is 600 W/mK. Determine surface area to achieve the desired heating? (30 points) Cpwater-4,18 kj/kgK, Cpgeothermal-4,31 kj/kgK.