| 摘要 |
PROBLEM TO BE SOLVED: To provide an environmental test device which is a cooling system enabling switching between one way operation and two way operation and hardly reducing a cooling capacity in switching with less change gradient in temperature as compared to the prior art.SOLUTION: A cooling system 7 includes: a low temperature side freezing circuit 20; and a high temperature side freezing circuit 21. The cooling system 7 can switch between one way operation and two way operation. When switching from one way operation to two way operation, a transition operation is temporarily executed, which makes a refrigerant pass through both of an evaporation part 33 for cooling an interior of a tank and an evaporation part 35 for cooling a capacitor. The transition operation makes the refrigerant pass through both of a main circuit 50 and an auxiliary circuit 51 of the higher temperature side freezing circuit 21, and in this state, the refrigerant is also circulated in the low temperature side freeing circuit 20. The transition operation is performed stepwise, and flow passages passing through five capillary tubes 41, 42, 43, 44, and 45 which constitute an expansion passage 36 for cooling the interior of the tank are completely opened at the beginning, and these passages are closed one by one as time elapses. |
