A critically charged refrigeration system will have:

In a critically charged refrigeration system, having no receiver is essential for maintaining the specific charge of refrigerant needed for optimal performance. Such systems operate under a condition known as "critical charge," where the amount of refrigerant is precisely calculated and controlled to ensure efficient operation and to maintain the desired thermodynamic properties.

The absence of a receiver in this scenario implies that the system does not have a storage tank for excess refrigerant, as the right amount of refrigerant is necessary to prevent both under and overcharging. When the refrigerant charge is balanced correctly, it allows for better heat transfer and overall efficiency in the refrigeration process, thereby optimizing the system's function.

In other types of systems, a receiver is used to hold excess refrigerant and to allow the refrigerant to accumulate, which is not suitable for critically charged systems. The choice of having a correctly sized receiver or incorporating multiple compressors is specific to the design and operation of other refrigeration systems, but for a critically charged system, the correct approach is to avoid a receiver altogether.