The mixed refrigerant JT (Joule-Thomson) cooling system has been investigated in this study. The mixed refrigerant is composed of completely non-flammable refrigerants while the preceding studies have focused on the flammable refrigerants. The experimental apparatus is constructed to examine the actual performance of the developed non-flammable mixed refrigerant JT cooling system. The extensive experiments have been conducted; the cold-end temperature of 178 K (-95℃) is achieved with the mixture composed
of N2, R14, R23, and R218 with 7%, 27%, 18%, and 48% mole fraction, respectively. The result shows the positive prospects of a non-flammable mixed refrigerant JT cooling system. The experimental result is discussed with the limitation of this study and the way of
improvement to achieve lower temperature.