Supercritical carbon dioxide refrigeration cycle system and method

The invention relates to the technical field of mine mining, and provides a supercritical carbon dioxide refrigeration cycle system and method.The system comprises a ground compressor, a first ejector, a gas-liquid separator and an air cooling system which are sequentially connected to form a circulation loop, and a bypass injection pipeline is connected to the portion, located between the ground compressor and the first ejector, of the circulation loop; the side injection pipeline is connected to the first injector; a kinetic energy recovery unit and at least one second ejector are sequentially arranged on the bypass ejection pipeline in the fluid flowing direction. High-pressure liquid-phase SCO2 compressed by the ground compressor is divided into two paths, one path enters the first ejector, the other path enters the kinetic energy recovery unit to generate power, then enters the second ejector to be ejected and then enters the first ejector to be evenly mixed with the liquid-phase SCO2 to be ejected, and