A Gamma type Stirling refrigerator optimization: An experimental and analytical investigation

The Design of Experiment (DOE) method is used for multi-objective optimization. Three parameters namely COP, cooling capacity and pressure drop are investigated in this optimization study. Only helium and carbon dioxide are considered for optimization because of their higher specific heat capacity and enthalpy with respect to air. The optimum working pressure for the carbon dioxide takes place at lower pressure than that of helium. When the importance and weight factors equal one, the optimum point for helium is obtained at working pressure and rotational speed of 9 bar and 451.1 rpm, respectively. Where, the optimum point for carbon dioxide is found at working pressure and rotational speed of 3.3 bar and 798.5 rpm, respectively.