A counter flow heat exchanger is to be designed to cool 900 kg/hr of oil from 60°C to 32°C using a fluid with Sp. heat 1.0 kJ/kg-K at 15°. The Sp. heat of the oil is 0.5kJ/gk-K and the maximum allowable exit temperature of the cooling fluid is 27°C. Work out the following:
(i) Sketch the system and show the temperature distribution.
(ii) Find NTU.
If the diameter of the tube is 2 cm through which the cooling fluid passes and the overall heat-transfer coefficient is 200W/m2-K, find the number of tubes required and the tube length. Assume density of the cooling fluid is 250 kg/m3. If the maximum velocity through the tube cannot exceed 2 m/s and the maximum length of the exchanger is limited to 12 m due to space restriction, find the configuration of the exchanger and sketch the final design.