Maximum work from temperature differences
uppose we have two buckets of water with constant heat capacities CA and CB, so that the relationship between the change in temperature of bucket A and the change in energy is
dUA = CAdT
with a similar equation for bucket B.
The buckets are initially at temperatures TA,0 and TB,0.
The buckets are used in conjunction with an ideal heat engine, guaranteed not to
increase the world's total entropy (FBN Industries, patent applied for).
1. What is the final temperature of the water in the two buckets?
2. What is the maximum amount of work that you can derive from the heat energy in the buckets of water?
3. If you just mixed the two buckets of water together instead of using the heat engine, what would be the final temperature of the water?
4. Is the final temperature in this case higher, lower, or the same as when the heat engine is used? Explain your answer.
5. What is the change in entropy when the water in the two buckets is simply mixed together?