To prevent liquid flood-back, a heat pump using a reciprocating compressor should be equipped with which component?

The correct choice is a suction accumulator. This component is essential in preventing liquid flood-back to the compressor in a heat pump using a reciprocating compressor. The suction accumulator serves as a reservoir that collects excess refrigerant and ensures that only vapor is sent to the compressor. When liquid refrigerant enters the compressor, it can cause damage since reciprocating compressors are designed to compress vapor, not liquid.

By maintaining the appropriate conditions, the suction accumulator allows the system to handle variations in refrigerant flow and pressure, thereby protecting the compressor from potential liquid slugging. It effectively separates vapor from any liquid refrigerant, allowing only vapor to be pulled into the compressor, which is crucial for maintaining operational efficiency and prolonging the life of the compressor.

The other components listed do not specifically address the issue of liquid flood-back. A check valve generally prevents backflow in piping systems, while a liquid line filter is used to remove contaminants from the refrigerant. A thermal expansion valve is responsible for regulating the flow of refrigerant into the evaporator but does not actively manage liquid refrigerant returning to the compressor. Thus, the suction accumulator is the most appropriate choice for preventing liquid flood-back in this context.