1. A shell-and-tube exchanger is to be used to cool hot oil from 90°C to 40°C using untreated cooling water entering at 18°C. the mass flow rates of the oil and water are 30 kg/s and 60 kg/s respectively. The exchanger is to be constructed from thin-walled copper tubes 2.5 cm in outside diameter. The oil acts as the shell-side fluid and the heat transfer coefficient associated with this flow is 600 Wm-2K-1. The thermal properties of the oil and water and the fouling factors are as in Q1. Determine the tube-length that would be required if:-

(a) 500 tubes used in a single tube pass

(b) 250 tubes are employed in an U-tube arrangement

A single shell pass is used in both cases.