Cooling system for fluid to be cooled

A cooling system comprising:

• a compressor configured to pressurize carbon dioxide to form pressurized carbon dioxide;
• a mixer configured to generate a mixed refrigerant in which the pressurized carbon dioxide and a solvent in a liquid state are mixed;
• a depressurization apparatus provided downstream from the mixer and configured to depressurize the mixed refrigerant, the depressurization apparatus including a valve;
• a separator configured to separate carbon dioxide in a gas state from the mixed refrigerant;
• a heat exchanger configured to exchange heat between the mixed refrigerant cooled through depressurization and a fluid to be cooled;
• and
• a second heat exchanger configured to cool the pressurized carbon dioxide or the mixed refrigerant using vaporized carbon dioxide or the mixed refrigerant,
• wherein the second heat exchanger is integrated with the heat exchanger,
• the heat exchanger is configured such that the mixed refrigerant and the fluid to be cooled always flow in opposite directions with respect to each other in the heat exchanger, and
• the second heat exchanger is configured such that the vaporized carbon dioxide or the mixed refrigerant and the pressurized carbon dioxide or the mixed refrigerant always flow in opposite directions with respect to each other in the second heat exchanger.