To account for a refrigerant circuit that could become restricted, a commercial refrigeration system's liquid receiver should be sized by how much larger than the total liquid volume in the system?

The answer indicates that the liquid receiver in a commercial refrigeration system should be sized at least 15% larger than the total liquid volume in the system. This sizing allows for potential restrictions in the refrigerant circuit, which can occur due to various factors like blockages, expansions, or changes in temperature and pressure. By allowing for this additional capacity, the system can accommodate fluctuations in refrigerant volume and maintain effective operation.

This extra 15% capacity ensures that there is enough room for liquid refrigerant to expand without causing pressure issues or operational inefficiencies. If the liquid receiver is too small, it may lead to flooding of the evaporator or starve the compressor of liquid refrigerant, both of which can lead to operational problems and decreased efficiency in the refrigeration cycle. The choice to size the receiver by this percentage ultimately promotes reliability and efficiency in the refrigeration system.