Liquefaction system and power generation system

A liquefaction system comprising:

• a storage tank which stores a substance, whose boiling point is equal to or lower than room temperature, in a liquid state;
• a superconducting motor which includes a superconducting magnet constituted by a superconducting material;
• a liquefier which includes a first compressor that is driven by the superconducting motor and that compresses the substance in a gaseous states and a first expansion section that changes the substance from a gaseous state to a liquid state by expanding the substance compressed by the first compressor, and which generates the substance in a liquid state to be stored in the storage tank;
• and
• a cooling circuit which includes a second compressor that is driven by the superconducting motor when the first compressor is being driven by the superconducting motor and that compresses a refrigerant, a first heat exchanger that cools the refrigerant by causing a heat exchange between the substance stored in the storage tank and the refrigerant compressed by the second compressor, a second expansion section that brings the refrigerant down to or below a critical temperature of the superconducting material by expanding the refrigerant cooled by the first heat exchanger, and a second heat exchanger that imparts cooling of the refrigerant to the substance by causing a heat exchange between the substance stored in the storage tank and the refrigerant after cooling the superconducting magnet, and which supplies the refrigerant brought down to or below the critical temperature by the second expansion section to the superconducting motor and cools the superconducting magnet down to or below the critical temperature, wherein,
• the first expansion section is a first expander or a first expansion valve,
• the second expansion section is a second expander or a second expansion valve.