Parallel compressor units are refrigeration systems that combine multiple compressors into a single rack, operating in tandem to meet cooling demands efficiently. These systems are widely used in commercial, industrial, and cold storage applications where reliability, scalability, and energy efficiency are critical.

The screw compressor in the screw parallel unit achieves the suction, compression and discharge of refrigerant gas by meshing the yin and yang rotors, so that the inter-tooth volume changes continuously. In the refrigeration cycle, the compressor sucks the low-pressure working fluid vapor from the evaporator, increases its pressure and sends it to the condenser, where it condenses into a high-pressure liquid. After throttling by the throttle valve, it becomes a low-pressure liquid and is sent to the evaporator, where it absorbs heat and evaporates to become low-pressure steam, thus completing the refrigeration cycle.

When multiple screw compressors are operated in parallel, they are connected together through common suction and exhaust pipes, and a centralized control system automatically adjusts the number of compressors in operation and energy output according to the cooling demand to achieve precise control of the cooling capacity.