Q$1)$ A Double pipe heat exchanger whose inner pipe is expected to be made of copper and the outer Jacket is to be made of schedule $40$ steel. Two fluids A and B flow though the pipes and are involved in heat transfer. The inlet and outlet temperatures of the hot fluid is C and D and that of the cold fluid is E and F respectively.

i$)$ Design a suitable double pipe heat exchanger

ii$)$ Comment on the mode of heat transfer with proper justification

iii$)$ Justify if your design is relevant and why can it be used for industrial applications

$1.$ Propylene Glycol $[$Inner pipe: Inlet $\backslash ((\backslash$mathrm$\{$C$\})=108^\{\backslash$circ$\}\backslash$mathrm$\{$C$\}\backslash ),$ Outlet $\backslash ((\backslash$mathrm$\{$D$\})=90^\{\backslash$circ$\}\backslash$mathrm$\{$C$\}\backslash )]$

$2.$ Propane $[$Outer pipe: Inlet $\backslash ((\backslash$mathbf$\{$E$\})=23^\{\backslash$circ$\}\backslash$mathrm$\{$C$\}\backslash ),$ Outlet $\backslash ((\backslash$mathrm$\{$F$\})=36^\{\backslash$circ$\}\backslash$mathrm$\{$C$\}\backslash )]$