1 - A shell-and-tube heat i exchanger operates with two shell passes and four tube passes. The shell fluid is ethylene glycol, which enters at 140°C and leaves at 80°C with a flow rate of 4500 kg/h. Water flows in the tubes, entering at 35°C and leaving at 85°C.
The overall heat-transfer coefficient for this arrangement is 850 W/m2.°C.
Calculate the flow rate of water required and the area of the heat exchanger.
2- The flow rate of glycol to the exchanger in Problem 1 is reduced in half with the entrance temperatures of both fluids remaining the same. What is the water exit temperature under these new conditions, and by how much is the heat-transfer rate reduced?