Research on a intelligent dual temperature box
A intelligent dual temperature box is researched in this paper. The dual temperature box utilizes cascade refrigeration system. R<sub>22</sub> is the refrigerant of high temperature circle system, and R<sub>13</sub> is the refrigerant of low temperature circle system. The R<sub>22</sub> system can operate alone or with the R<sub>13</sub> system. So the dual temperature box can achieve two vapor temperatures of -65°C and -20°C. And the refrigerant system of it can operate stable while the temperature is -65°C.