Hysteresis losses in the heat transfer between compressing or expanding gas and the adjacent wall is said to play an important role in Stirling machines, where it increases the amount of required p-V work. Previous studies have linked hysteresis loss with the pressure phase shift. In the context of this research, the effect of the pressure phase shift on the net p-V work in a single space is examined.

A Sage model of a single space piston-cylinder device is used to investigate the underlying mechanisms of the pressure phase shift. The Sage model is validated using an experimental piston seal rig. In addition, the time dependence of heat transfer is discussed along with how it affects the pressure phase shift, using an iterative model. The Schmidt equations were manipulated to determine the phase shift between pressure and volumetric oscillation in an ideal Stirling refrigerator.

The results of this investigation are surprising. It was found that even in the case of an idealized Stirling refrigerator, the phase shift between pressure and volume is non-zero in order to produce a refrigeration effect.