Entropy balance and performance characterization of the narrow basic pulse-tube refrigerator

The basic pulse-tube refrigerator is studied using near-isothermal theory, The theory has been extended to include evaluation not only of the enthalpy flux, but also of entropy, This allows for dividing the enthalpy flux into heat and work at the extremities of the tube, and as a result, the pulse-tube performance can be determined, Except for a simple numerical integration, this study proceeds entirely in closed form, so that an investigation of the complete parameter space can be performed fairly easily, Since the device is inherently irreversible, the coefficient of performance is limited to values lower than the Carnot limit, and the results show that coefficients of performance up to about 50% of the limit are possible, but for relatively small temperature differences, outside of the cryogenic range, Still, in the usual arrangement with regenerator, a properly designed basic pulse-tube, with high-pressure amplitude and a suitable ratio between the volume of the tube and the volume of the cooler or reservoir, may conceivably remain competitive with the orifice-type device, in which, in contrast with the basic pulse-tube, an adiabatic loss at the cold end is unavoidable.