Animation of the Stirling engine working principle
This animation of the working principle of the Stirling engine helps to understand how Demotech's design for a rotatary Stirling may work as drive for the ventilating pump.
http://www.keveney.com/Vstirling.html

Free piston Stirling engines for cooling
This product shows the sophisticated level of design and application of the Stirling principle. This link also contains a PDF with clear general information on many aspects of Stirling engines.
http://www.globalcooling.com/technologyoverview.html

Educational models to understand Stirling Engines
http://www.bekkoame.ne.jp/~khirata/english/make.htm