Temperature at cold outlet, cold mass fraction and isentropic efficiency in the Ranque-Hilsch Vortex Tube (RHVT) are experimentally measured and derived. For the experiment, different pressures (absolute) (between 290 to 800 kPa) were applied as source, 3 types of swirl generator and 3 shapes of conical valve were used. The lowest temperature obtained during the experiment was −11.6°C for a cold mass fraction (μc = 0.947) which gave the highest isentropic efficiency (ηis= 0.336) at source pressure of 790.2 kPa. However, the highest cold mass fraction (μc = 1.024 was given by source pressure of 790.2 kPa with isentropic efficiency (ηis) of 0.042 and the cold temperature was 20°C.