Mechanical Engineering - Thermodynamics - Discussion

Throttling is an expansion process. In this process, a high-pressure liquid is passed through the narrow path and converted into a low-pressure liquid. In this process, there is no heat exchange. In this process, the change in enthalpy is zero. That's why it is called the constant enthalpy process.

In refrigerator, we can see the throttling device where enthalpy remains the same in the process but there will be pressure loss to attain low temperature. So refrigerant pass through small dia pipes to achieve the above one.