Design of a mixed refrigerant Joule-Thomson cryopreservation chamber

The process of cryopreservation involves the cooling of biological materials to a temperature in the range of 100 -150 K in an insulated chamber. The Mixed Refrigerant Joule-Thomson (MRJT) cryocooler technology, which is the focus of the present study, could be employed to cool the cryo-preservation chamber. The MRJT cryocooler uses a multi-component mixture of nitrogen-hydrocarbons as the working fluid. The design of the cryo-preservation chamber involves compressor selection with appropriate oil filter mechanism, MRJT cryocooler design and design of vacuum chamber. The heat exchanger design is a core aspect of the cryo-preservation chamber design. A tube-in-tube helically coiled heat exchanger is analyzed numerically to get an optimal design for the heat exchanger. Recently published correlations have been applied to estimate the boiling and condensation heat transfer coefficients. The predicted heat transfer coefficients are utilized by the algorithm to determine the temperature profile along the heat exchanger which is then used to compute the optimal design parameters of the heat exchanger. The estimated parameters are compared with the prevailing experimental data to elucidate the applicability of the model. After validation, the algorithm is used to design the heat exchanger for the cryopreservation chamber.