1) You cannot win.
2) You cannot break even except on a very cold day.
3) It never gets that cold.

http://www.howstuffworks.com/question608.htm
http://www.stirlingengine.com/


Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/qz3.pdf