Q1: Air is to be heated by condensing steam. Two heat exchangers are available (i) a shell and tube heat exchanger and (ii) a finned tube heat exchanger. Tube side heat transfer area are equal in both the cases. The recommended arrangement is

ANS:B - finned tube heat exchanger with air outside and steam inside.

Given that air is to be heated by condensing steam, we typically want the fluid with the higher heat capacity (steam) to flow through the side with more surface area available for heat transfer, which is usually the shell side in a shell and tube heat exchanger. Therefore, the recommended arrangement is: "Shell and tube heat exchanger with air on the shell side and steam inside the tubes." This arrangement allows the steam, which has a higher heat capacity, to flow through the tubes where it can efficiently transfer heat to the air flowing on the shell side. Additionally, the use of a shell and tube heat exchanger provides a large surface area for heat transfer, facilitating efficient heat exchange between the steam and the air. So, the recommended option is: "shell and tube heat exchanger with air on the shell side and steam inside the tubes."