Ejector in low lift applications

Ejectors in low lift applications should deliver the highest possible mass flow. They are usually used to extract the entire mass flow that is evaporated in the system and deliver it back to the intermediate pressure vessel. The limiting factor here is the mass flow which determines how much the ejector can raise the pressure or how high the intermediate pressure may be so that the refrigerant can be fed back.

Liquid phase and gas phase are separated in the intermediate pressure vessel. The gas phase is extracted by the compressor and represents the motive mass flow. The liquid phase is still available to supply the evaporator and represents the suction mass flow.

Ejectors in low lift applications are used as robust "refrigerant pumps", as they can also pump a gas-liquid mixture. This allows operation with a flooded evaporator. The evaporator surface can be used without a superheat section and the evaporating temperature can be raised without endangering the compressor.

Design example of a low lift ejector created with the help of BITZER SOFTWARE see here.