1. Essentially different, refrigerants, also known as refrigerants, refrigerants, and refrigerants, are intermediate substances used to complete energy conversion in various heat engines.
In indirect cooling refrigeration units, the transfer of heat from the cooling system (object or space) to the refrigerant as an intermediate cooling medium is accomplished by the refrigerant. This intermediate cooling medium is also referred to as the second refrigerant. In air-conditioning engineering, industrial production and scientific experiments, refrigeration equipment is usually used to indirectly cool the object to be cooled, or to transport the cold air generated by the refrigeration equipment over long distances. At this time, the intermediate substance needs to be cooled in the evaporator. It is then used to cool the object to be cooled, and this intermediate substance is called a coolant.
2. The principle is different. The circulation of the 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 transfer the absorbed heat to the refrigerant while absorbing the refrigerant. Cooled by refrigerant again. The use of a carrier refrigerant allows the refrigerant to be concentrated in a smaller circulation system and transported to remote cooling equipment. The refrigerant absorbs heat from the object to be cooled at a low temperature and transfers it to the higher temperature cooling water or air. In vapor compression refrigerators, refrigerants that can be liquefied at room temperature or lower are used as refrigerants, such as Freons (fluorocarbons, bromine, chlorine and bromine derivatives of saturated hydrocarbons) and azeotropic refrigerants (from two freons, forming an azeotropic solution in a certain proportion), hydrocarbons (propane, ethylene, etc.), ammonia, etc.
In gas compression refrigerators, gaseous refrigerants such as air, hydrogen, helium, etc. are used, which are always gaseous in the refrigeration cycle. In absorption refrigerators, a binary composition consisting of absorbent and refrigerant is used. Solutions as working fluids, such as ammonia water, lithium bromide (molecular formula: LiBr. White cubic crystal or granular powder, easily soluble in water) and water; steam jet refrigerators use water as a refrigerant.