Heat transfer method

A heat transfer method using a heat transfer system, the heat transfer system including

• a heat source unit in which heat is configured to be exchanged between a heat transfer medium and a heat source,
• a utilization unit in which heat is configured to be exchanged between the heat transfer medium and a temperature adjustment target,
• a first flow path that connects the heat source unit and the utilization unit and through which the heat transfer medium is configured to flow from the heat source unit to the utilization unit,
• a pump configured to circulate the heat transfer medium in the first flow path,
• a second flow path that connects the heat source unit and the utilization unit and through which the heat transfer medium is configured to flow from the utilization unit to the heat source unit, and
• a compressor configured to circulate the heat transfer medium in the second flow path,
• the method comprising:
• using, as the heat transfer medium, inorganic hydrate slurry in which an inorganic hydrate that absorbs heat when dissolved in water is mixed with water;
• and
• controlling the heat transfer system, including controlling the pump and/or the compressor, so that a temperature of the heat transfer medium flowing through the first flow path and a temperature of the heat transfer medium flowing through the second flow path become equal to or below a melting point of the inorganic hydrate;
• wherein
• an amount of the inorganic hydrate dissolved per unit mass of water in the heat transfer medium flowing through the first flow path is different from an amount of the inorganic hydrate dissolved per unit mass of water in the heat transfer medium flowing through the second flow path.