On 2009-10-29, ATP* wrote:
True. Yet I still hear this type of "reasoning" all the time. Should be a
simple concept even for the technically challenged, for example, people who
argued here that you can compress air and allow it to expand (while doing no
useful work) with no loss of energy.

That would be almost possible if compressing and expanding was done
very quickly, before compressed air cools.

i