Abstract: The PR equation is used to calculate the refrigerating capacity of binary cryogenic mixtures containing nitrogen and alkanes. The effects of inlet pressure, standard boiling point and composition on the isothermal Joule-Thomoson effect when using these mixtures are also revealed. The refrigerating capacity will be increased by using binary cryogenic mixtures in a Joule-Thomoson cryocooler. And also, the inlet pressure will be decreased at the same refrigerating capacity.

Key words: mixtures, isothermal Joule-Thomoson effect, cryogenics