Thermodynamic optimization of a helically coiled heat exchanger for Joule-Thomson refrigerators using response surface methodology.

In this study, an attempt is made to evaluate the effect of certain geometrical parameters on thermodynamic performance of the recuperator in the miniature Joule-Thomson cryocooler. Tube length “L”, tube diameter “Dt”, rib effect coefficient “S” and shell diameter “Ds” are selected as influencing parameters. A novel optimization model is developed using Response Surface Methodology (RSM) based on the available work loss minimization for the recuperator. The adequacy of the model is examined using the Analysis of Variance (ANOVA). The final optimization results show that an optimum combination of the geometrical parameters of the recuperator exists that leads to a minimum available work loss at certain conditions. It has been proven that the relative error of the optimum results is less than 1.4%. The model and results presented here for the optimization of the recuperator may provide a helpful guidance and a new way for the optimization of J-T cryocooler.