The refrigerant injection system
The RI system is an operating function of the CM-RC-01. It injects liquid refrigerant according to requirements, thus ensuring the thermal application limits during low temperature applications, such as with refrigerants R407A, R407F, R448A and R449A.
When a defined discharge gas temperature is exceeded, liquid refrigerant is injected directly into the suction gas chamber of the compressor via the RI injection nozzle. There it flows against the hot cylinder walls. The liquid refrigerant evaporates, cools the cylinder area and simultaneously lowers the temperature of the superheated suction gas flowing from the motor side. Even with single stage compression, a sufficiently low discharge gas temperature is maintained. In case of insufficient cooling or extreme operating conditions, the CM-RC-01 switches off the compressor via the discharge gas temperature monitoring.
The design and control of the refrigerant circuit have a significant influence on the injection cycles and thus on the overall efficiency of the system: Suction gas superheat and the difference between condensing and suction gas pressures should be kept as low as possible within the application limits. Ensure the minimum necessary suction gas overheat.
Observe these points when planning the system:
- Keep pipe sections short.
- Keep pressure loss in all components as low as possible.
- Keep the temperature difference as low as possible:
- Ensure low icing of the evaporator.
- Keep condenser clean.
- Keep condensing temperature low in a controlled manner.