SUMMARYA technique for calculating the e$ciency and power of Stirling machines is presented. This technique is based on the First Law of Thermodynamics for processes with "nite speed and the Direct Method for closed systems. In order to apply the Direct Method to Stirling Cycles, a new and novel PV/Px diagram is presented that shows the e!ects of pressure losses due to friction, "nite speed and throttling processes in the regenerator of the Stirling engine. The method used for the analysis of this irreversible cycle with "nite speed involves the direct integration of equations based on the "rst law for processes with "nite speed to obtain the cycle e$ciency and power directly. This technique is termed the Direct Method. The results predicted by this analysis are in good agreement with the actual engine performance data of 12 di!erent Stirling engines, over a range of output from economy to maximum power. This provides a solid veri"cation that this analysis, based on the Direct Method, can accurately predict actual Stirling engine performance, particularly with regard to e$ciency and output power. In addition to the powerful predictive capabilities of the Direct Method, the new PV/Px diagram for the Stirling cycle is both an e!ective and an intuitive tool for explaining the operation and design of Stirling machines.

No abstract

No abstract