For more than eighteen years, the author has been engaged in the development of Stirling engines and coolers. The author has developed a very simple harmonic graphic vector analysis for the first estimation of performance of various Stirling machines including engine, cooler, and VM. (Vuilleumier) machines. This has been shown to be very useful for early estimation and understanding of each machine. So at this time, the author want to report this method.
This method uses the Schmidt assumption at its base, and harmonic approximation, that was called the ellipsoidal assumption by the author previously ( 1 ).
This method is applied to α, β, γ type Stirling machines and generalized three temperature machine including VM. machines. It provides very easy graphic way to show which cylinder generates power or coldness and how much power, or heat is generated, utilizing volume variation vectors (for each cylinder and the total volume) and a pressure variation vector.
The author hopes this method is very helpful for the understanding, basic improvements, and development of new Stirling machines.