Multi-objective optimization of precooled JT cryocooler working at liquid hydrogen temperature

With the advantages of no moving parts at low temperature, flexibility and simple structure, the precooled Joule-Thomson (JT) cryocooler working at liquid hydrogen temperature has the potential to be applied in the liquid hydrogen zero boil-off (ZBO) storage system in space. For JT cryocooler used in aerospace, cooling capacity, efficiency and mass are key parameters which should be considered simultaneously. For this reason, in this study, a theoretical model of the precooled JT cryocooler working at liquid hydrogen temperature which is composed of the heat exchangers, the JT compressor and the precooler is established. The target cooling capacity of the cryocooler is 10 W at liquid hydrogen temperature. Multi-objective optimization method is introduced to comprehensively optimize input power and mass. The Pareto frontier consisting of a series of non-dominated solutions is obtained. The linear programming technology of multidimensional analysis preference (LINMAP) method is used to select the final optimal solution from the Pareto frontier. The multi-objective optimization results of input power and mass of the cryocooler are 3484.72 W and 40.92 kg, respectively.