In most commercial refrigeration systems, where is the excess refrigerant stored when not in use?

The liquid receiver is the correct answer because it serves as a storage container for excess refrigerant in a refrigeration system. When the refrigeration system operates, it continually circulates refrigerant through various components. During this process, some excess refrigerant may accumulate. The liquid receiver is designed to hold this refrigerant, preventing it from condensing in other parts of the system, thus ensuring efficient operation. It allows for the management of refrigerant levels within the system, providing a buffer that accommodates fluctuations in refrigerant demand across the refrigeration cycle.

In contrast, the evaporator's primary function is to absorb heat from the environment to facilitate cooling, while the compressor's role is to increase pressure and circulate refrigerant through the system. The expansion valve controls the flow of refrigerant into the evaporator, aiming to optimize cooling efficiency but does not store refrigerant. These components do not serve as storage tanks; their functions are focused on heat exchange and refrigerant flow management rather than excess refrigerant retention.