How does a turboexpander generate cooling?

How does a turboexpander generate cooling?

A turboexpander is a rotary chiller. When gas at a certain pressure enters the expander’s spiral tube, it is evenly distributed onto the guide vanes, which are equipped with nozzle blades. The gas converts its thermodynamic energy into flow energy in the nozzles, reducing its pressure and heat. The high-speed airflow strikes the propeller, causing it to rotate and perform work externally, converting the kinetic energy of the gas into mechanical energy.
From the perspective of the entire process of gas flowing through the expander, the reduction in gas pressure is an expansion process, simultaneously transferring work to the outside. This external work is achieved by consuming energy within the gas, reflecting a decrease in temperature and heat. This removes some energy from the gas, often referred to as cooling capacity.