Exergy analysis and performance of a Ranque-Hilsch Vortex Tube (RHVT) with various nozzle cross-section areas (NCSA = 3 × 3, 4 × 4, 5 × 5 mm2) were determined under inlet pressures (Pi) of 260, 300 kPa (absolute) pressurized air. The maximum difference in the temperatures of hot output and cold output streams was obtained for NCSA = 3 × 3 mm2. The total inlet exergy (∑Ėi), total outlet exergy (∑ĖO), total lost exergy (∑ĖLost) and exergy efficiency (η, %) were calculated. It was determined that the exergy efficiency of the system, varied between 1% and 39%, and the highest exergy efficiency was obtained for NCSA = 3 × 3 mm2. The exergy efficiency strongly depends on the level of Pi, ξ and vcold. Variation of the exergy efficiency decreased with decreasing Pi, ξ, v cold and the highest and lowest exergy efficiencies were found when the values of Pi, ξ, vcold reached maximum and minimum levels, respectively. © 2010 Elsevier Ltd and IIR. All rights reserved.