When running three compressors, how would you best describe the state of refrigerant leaving the third evaporator coil?

The state of the refrigerant leaving the third evaporator coil can be described as superheated vapor when considering the operational conditions of typical refrigeration cycles. In a multi-compressor system, refrigerant is typically evaporated in the evaporator coils, where it absorbs heat and changes from liquid to vapor.

Superheated vapor refers to vapor that has been heated further beyond its boiling point at a given pressure. In the context of refrigerant systems, as the refrigerant absorbs heat in the evaporator, it transforms from a liquid to a vapor state. If the evaporator is designed to allow for complete evaporation, which is ideal for efficient thermal exchange, the refrigerant exiting the coil will be in a vapor state – specifically, superheated vapor, as it will have absorbed additional thermal energy during its passage through the coil.

This state is crucial for maximizing the system's efficiency as it ensures that the refrigerant is fully vaporized before entering the compressor. Compressing a vapor rather than a mixture of liquid and vapor enhances the performance and protects the compressor from potential damage associated with liquid slugging. Thus, in a well-designed system, the refrigerant leaving the third evaporator coil would indeed be superheated vapor, indicating a successful phase change and readiness for compression.