In this study, thermodynamic analysis of a counter-flow vortex tube is made. Equations are derived for cold mass fraction (y(c)), entropy generation and irreversibility. Also, efficiency terms are defined based on the Carnot cycle by considering vortex tubes as both a cooling machine and a heat pump. Experiments are performed for various values of design parameters and working conditions. Experimental data obtained is then analysed thermodynamically. It is disclosed that irreversibility increases with an increase in the length of the helical vortex generator and in the inlet pressure. Both cooling and heating efficiencies are shown to decrease with an increase in the length of the helical vortex generator.