Study on cooling capacity characteristics of an open-cycle Joule-Thomson cryocooler working at liquid helium temperature

Abstract It is important to study on the cooling capacity characteristics of a Joule-Thomson cryocooler for saving energy and space usage in space applications. For a Joule-Thomson cryocooler working at liquid helium temperature, the intrinsic mechanism for the difference between specific cooling capacity and specific latent cooling capacity is revealed. Based on thermodynamics, the steady working states of a Joule-Thomson cryocooler with different typical high pressures are analyzed systematically. The values of specific cooling capacity and specific latent cooling capacity are found to be affected by the high pressure in different ways. Meanwhile, the overloaded destabilization, which is caused by the heat load exceeding the cooling capacity of the Joule-Thomson cryocooler, is further explained. The temperature behaviors under typical overloaded conditions are illustrated theoretically. All these characteristics are verified with the experimental results acquired from an open-cycle Joule-Thomson cryocooler working at liquid helium temperature.