$1.$Consider the following parallel$-$flow heat exchanger specification:

Cold flow enters at $40\backslash$deg C: Cc $=20000$ W$/$K

Hot flow enters at $150\backslash$deg C: Ch $=10000$ W$/$K

A $=30$m$2$

U $=500$ W$/$m$2$K

Determine the heat transfer and exit temperatures.

$2.$Suppose that we had the same kind of exchanger as we considered in

Question $1,$ but that the area remained unspecified as a design variable.

Then calculate the area that would bring the hot flow out at $90\backslash$deg C$.$