Q$1$:Two alternative systems are under consideration for bringing a stream of air from

$17C$ to $52C$ at an essentially constant pressure of $100$ kPa $.$

System $1$: The air temperature is increased as a consequence of the stirring of a liquid

surrounding the line carrying the air.

System $2$: The air temperature is increased by passing it through one side of a counter$-$

flow heat exchanger. On the other side, steam condenses at a pressure of $100$ kPa from a

saturated vapour to a saturated liquid.

Both systems operate under steady conditions and are sufficiently insulated to prevent

significant heat transfer with the surroundings. For each of the two systems, calculate the

rate of entropy generation, in $k\frac{J}{K}$ per kg of air passing through the system.

System $1$

System $2$