A METHOD FOR DETERMINING THE PERFORMANCES OF STIRLING MACHINES BASED ON THE FIRST LAW FOR PROCESSES WITH FINITE SPEED AND USING A PV/PX DIAGRAM

Abstract

A technique for calculating the efficiency and power of Stirling machines is presented. This technique is based on the First Law of Thermodynamics for processes with finite Speed. A new and novel PV/Px diagram is presented that shows the effects of pressure losses due to friction, finite speed and throttling processes in the regenerator of the Stirling engine. The method used for the analysis of this irreversible cycle with finite speed involves the direct integration of equations based on the First Law for processes with finite speed to directly obtain the cycle efficiency and power. This technique is termed the Direct Method. The results predicted by this analysis were in good agreement with the actual engine performance data of tweve different Stirling engines over a range of output from economy to maximum power. This provides a solid verification that this analysis can accurately predict actual Stirling engine performance, particulary with regard to efficiently and output power.