The ideal adiabatic cycle - a rational basis for Stirling engine analysis

Abstract

Since 1871, the Schmidt Ideal Isothermal analysis has been the baseline model of Stirling engine analysis. This is mainly since it is the only analysis which can provide a closed form solution. However, the isothermal assumption leads to surprizing conclusions, such as the heater and cooler being redundant to the engine operation. With the proliferation of the microcomputer, the Ideal Adiabatic simulation is the most suitable contender for the basic analysis. This paper reviews the Ideal Adiabatic analysis, as well as showing how this analysis can be utilized in order to evaluate the various practical effects of non-ideal regenerators and heat exchangers, including heat transfer and pressure drop losses. A new definition of regenerator effectiveness as applied specifically to Stirling engines is proposed and discussed in the light of the Ideal Adiabatic analysis. The results are validated against more sophisticated computer simulation techniques, and are found to be extremely accurate.