13 C7a Due 3/17

1. Do 7.18 in the hardcover or 7.13 in the softcover.

2. For each of the cases below determine if the heat engine satisfies the first law, and if it does, if it satisfies the second law, and if it does, whether it is now a useful heat engine.

   $\dot Q_H$	$\dot Q_L$	$\dot W$	1st law?	2nd law?	useful
   5	4	3
   5	3	2
   5	5	0
   5	0	5
   0	5	-5
   -5	5	-10
   5	-5	10
   5	10	-5

3. For each of the cases below determine if the heat pump or refrigeration cycle satisfies the first law, and if it does, if it satisfies the second law, and if it does, whether it is now a useful heat pump or refrigeration cycle.

   $\dot Q_H$	$\dot Q_L$	$\dot W$	1st law?	2nd law?	useful
   5	4	3
   5	3	2
   5	5	0
   5	0	5
   0	5	-5
   -5	5	-10
   5	-5	10
   5	10	-5

4. Water at 25$^\circ$C and 100 kPa enters an isobaric heat exchanger at a rate of 5 kg/s and is heated into saturated steam without droplets in it. The heat is provided by a heat pump with a coefficient of performance of 3. Determine the amount of power required by the heat pump.