A shell-and-tube heat exchanger with one shell pass and two tube passes employs condensing steam at 1 atm on the shell side to heat 10 kg/s of engine oil from 50 to 60°C in the tubes. The steam enters as saturated vapor and leaves as saturated liquid with hfg=2.26 MJ/kg. The hot condensate leaving the exchanger is subsequently used to heat water to 60°C in another shelland-tube exchanger, with the condensate occupying the shell side and the cooler water flowing in the tubes. The cool water enters at 20oC.

1. Make your suitable selection for the tube materials and sizes (diameter, thickness) of both exchangers.

2. Determine values of U for both heat exchangers. Do not neglect wall resistances and take into account the fouling inside of tubes.

3. Determine the size of the steam condenser and suggest sizes for the exchanger which serves as the water heater. Please consider the space limitations and cost of manufacture (in practice, the desirable tube length must be less than 2 m).

4. For each exchanger suggested, indicate the amount of water which may be heated.

5. Comments on the suggested tube arrangements