BobS wrote:
Here's an interesting site and FAQ about Stirling engines.

It is a Stirling engine and they are in use today in way's you never thought
about. From submarines to cooling infrared devices..... according to the
FAQ on this site.

http://www.stirlingengine.com/faq/on...ublic&faq_id=1


I'm not so sure that its a true Stirling engine. Notice that the
heating
part of the cycle corresponds to when the water is being heated, and
the cooling part of the cycle occurs when the water level in the
heater drops below the heater so I think that evaporation and
condensation of the water plays a role. There is no phase change in
a true Stirling engine, right?

It looks to be a more sophisticated version of the 'putt-putt' toy
boat engines made in India and sold as toys. Basicly a vaccuum
engine (low-pressure steam engine) with the water doing double
duty as both the working fluid and the counterweight.

This one would operate without actually boiling, depending
on the vapor pressure of water as a function of temperature.

But if most of the volume change in the air loop is due to expansion
rather than evaporation then the phase is just a means of transfering
heat to the air and it would be predominately a Stirling engine.

--

FF