On 8 September 2012 06:55, Harry Veeder <hveeder...@gmail.com> wrote: > > When that system is submerged in the cold bath, the > spring will become stiffer and this will translate into more pressure > on the ends of the box, and therefore more potential energy. >
I think that here you have just 'normal' heat engine. The heat energy/mass of the hot spring is transformed into the spring energy/mass of the cooler and stiffer spring. That is, heat energy is transformed into useful (potential) work. Jones's video demonstrated more clearly how this change in crystal lattice structure due to temperature change can be utilized to create useful work from heat. With nitinol springs this 'phase change' is more extreme than with regular springs. —Jouni