Refrigeration is the absorption of heat, when the heat is absorbed, the temperature will drop. To achieve this purpose, is the refrigerant compression, when the refrigerant is compressed, its internal energy will increase, then its pressure and temperature will increase, through the cooling is the temperature is lowered, and then the volume expansion of the refrigerant decompression, then it has to absorb heat. Air conditioning is an outdoor fan compressor refrigerant compression, and then cooling, the cooled refrigerant is sent to the indoor hanging through the insulation of the copper tube, the refrigerant for the expansion of the decompression, then it has to absorb the heat of the room, so that the indoor temperature is lowered. After absorbing the heat, the refrigerant is returned to the outdoor unit, compressed and cooled again by the compressor, and sent to the indoor unit, thus circulating the operation, and continuously absorbing the indoor heat.
For the large-scale oxygen generator, there is an air compressor to compress and cool the air, adsorb the water and carbon dioxide, and then through the expansion of the expander to expand and cool, and then through the subcooler to further expand and cool, and ultimately make the air liquefied. Oxygen and nitrogen are separated by distillation in the distillation tower.