What is the difference between carrier refrigerant and refrigerant

1. Different in nature, refrigerants, also known as refrigerant, refrigerant and snow, are intermediate substances used to complete energy conversion in various heat engines.
In an indirect cooling refrigeration unit, the carrier coolant completes the transfer of heat from the cooling system (object or space) to the refrigerant acting as an intermediate cooling medium. The intermediate cooling medium is also called the second refrigerant. In air conditioning engineering, industrial production and scientific experiments, refrigeration equipment is often used to indirectly cool objects to be cooled, or to transport cold air generated by refrigeration equipment over long distances. At this point, the intermediate material needs to be cooled in the evaporator. It is then used to cool the object to be cooled, and the intermediate substance is called the secondary refrigerant.
2. Different principles. The cycle of the secondary refrigerant is first cooled by the refrigerant in the evaporator, then sent to the cooling equipment to absorb the heat of the cooling system, and then returned to the evaporator to absorb the refrigerant and transfer the absorbed heat to the secondary refrigerant. It's cooled by the refrigerant again. The use of carrier coolers allows the refrigerant to be concentrated in a smaller circulation system and transported to remote cooling equipment. The refrigerant absorbs heat from the cold object to be cooled and transfers it to the warmer cooling water or air. In a vapor compression refrigerator, refrigerants that can be liquefied at room temperature or lower are used as refrigerants, such as freon (fluorocarbons, bromine, chlorine and bromine derivatives of saturated hydrocarbons) and azeotrope mixtures (from two freons to form a proportional azeotrope solution), hydrocarbons (propane, ethylene, etc.), ammonia, etc.
In a gas compression refrigerator, gas refrigerants, such as air, hydrogen, helium, etc. are used, and they remain gaseous throughout the refrigeration cycle. In an absorption refrigerator, a binary composition consisting of an absorber and a refrigerant is used. A solution, such as ammonia, lithium bromide (molecular formula: LiBr), used as a working fluid. White cubic crystal or granular powder, soluble in water) and water; Steam jet refrigerators use water as refrigerant.