Which compressor is commonly started first in a two-stage system?

In a two-stage compression system, the first compressor that is typically started is the low stage compressor. This is because its primary function is to lift the refrigerant pressure from low to intermediate levels, allowing the refrigerant to be properly compressed before it enters the high stage compressor.

Starting with the low stage compressor ensures that the system can efficiently manage refrigerant flow and pressure, providing a stable foundation for the entire process. It allows for effective cooling and heating efficiency, as the low stage compressor handles initial vapor compression, preparing it for the higher pressures dealt with in the next stage. Hence, starting with this compressor helps maintain optimal system operation and prevents undue stress on the subsequent stages of compression.

The correct option emphasizes the importance of the sequencing in the operation of compressors in a refrigeration cycle, thereby enhancing performance and reliability in the system.