Re: Curie point engine vs Carnot efficiency

From a college thermodynamics textbook I have that a heat engine is "... 
any control mass to and from which energy is transferred as heat and from 
which energy is transferred as work."  I could not find a web reference, 
or other reference, that referred to a curie point heat engine, but did 
find the following reference describing a demonstration of the curie 
point.
 http://www.exploratorium.edu/snacks/curie_point.html

For that demonstration of the curie point, if I chose the metal object to 
be the control mass, electrical energy is used to heat the control mass, 
so that it cannot be said that energy is transferred to the control mass 
as heat.  From the illustrations in the above web reference, it also 
appears any work produced is due to the potential energy provided to the 
control mass as a starting condition, rather than a cyclic release of 
work more common in a heat engine.

In summary, Carnot efficiency does not apply to the demonstration of the 
Curie point because the later is not a heat engine.

Additional information on heat engines is available in any college level 
thermodynamics or physics textbook.

Thanks for your question.

sid