Design, Heat Leakage Analysis and Stirling Cryocooler Option of Stirling-type Lyophilizer

Based on referring to the relevant patents, it was found that the traditional lyophilizer refrigeration system has the disadvantages of large volume and high power consumption. Meanwhile, considering the context of advocating low carbon emission and environmental protection, the use of energy-saving refrigeration technology and the use of non-fluorine and harmless refrigerants are the trends of future development. In order to solve the problems of complex refrigeration system, high energy consumption and large volume of traditional lyophilizer, improve the operation performance of lyophilizer, enhance the reliability of lyophilizer operation, the paper designs a Stirling-type lyophilizer with working temperature -70 ℃. In order to solve the traditional lyophilizer problems and enhance the lyophilizer reliability, the paper designs a Stirling-type lyophilizer with a working temperature of -70°C. The paper designs a Stirling-type lyophilizer with working temperature -70 ℃. Stirling cooling has the advantages of ultra-low refrigeration temperature and high cooling speed. Based on the above advantages, combining the characteristics of the lyophilization box, a Stirling- type lyophilizer with a capacity of 0.120 m3 and a shelf area of 0.4 m2 is designed. The Stirlingtype lyophilizer refrigeration system structure is analyzed. The flat plate heat pipe to transfer the cold is used. The rigid polyurethane as the insulation material of the lyophilization box is studied. The heat leakage calculation method of the lyophilization box is given. Based on the advantages of ultra-low temperature, fast cooling and high efficiency of Stirling cooling, a lyophilizer with a capacity of 0.120 m3 and a shelf area of 0.4 m2 was designed by combining the characteristics of the lyophilization box and Stirling refrigeration technology. The structure of the refrigeration system of lyophilizer was analyzed, a flat plate-type heat pipe to conduct the cold was used, the rigid polyurethane as the insulation layer was studied, and the calculation method of heat leakage of the lyophilization box was given. Stirling cryocooler was selected based on the heat load of the lyophilization box, the experimental study of testing cryocooler was conducted and the feasibility of the design was verified. Stirling cryocooler is selected based on the lyophilization box heat leakage. The experimental test of the Stirling cryocooler is conducted. The feasibility of the design is verified. The Stirling cryocooler, with a charging pressure of 2.9 MPa and an operating frequency of 68 Hz, could achieve -87.057°C within 24 min. The lowest refrigeration temperature could be maintained at - 100.286°C after 97 min. The cooling capacity obtained is 40.0 W at an input power of 99.2 W, and the COP is 0.403. The cryocooler with a charging pressure of 2.9 MPa and an operating frequency of 68 Hz, could be reduced to -87.057 °C within 24 min, and the lowest refrigeration temperature could be maintained at -100.286 °C after 97 min. Stirling refrigeration technology is suitable for use in lyophilizer and Stirling refrigeration technology improves the robustness of the lyophilizer refrigeration system.