The receiver and the accumulator are two different vessels with different roles within the refrigeration circuit.

Liquid receiver

Stores liquid refrigerant on the high side of the system and helps ensure a steady supply to the expansion device.

Suction accumulator

Placed on the suction line and helps prevent a large quantity of liquid refrigerant from reaching the compressor.

Why they are different

One manages liquid on the high side, while the other protects the compressor on the low side.