Hot oil at 110°C is to be cooled in a double-tube parallel-flow heat exchanger. The copper inner tubes have a diameter of D;=1.9cm and negligible thickness. The inner diameter of the outer tube (the shell) is Do=8cm. Water flows through the tube at a rate of 0.7 kg/s, and the oil through the shell at a rate of 1.2 kg/s. If the inlet and outlet temperatures of water are 30°C and 60°C respectively, determine (a) the overall heat transfer coefficient of the heat exchanger (b) the length of the HX required to achieve the desired cooling using LMTD method, (c) the effectiveness of the heat exchanger. (d) Do you recommend changing the sides of the fluids? In other words, water flowing through the shell and oil flowing through the tube. Please state your reasons clearly.

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