Which statement about the compression ratio of a reciprocating compressor is true?

The correct statement is that the compression ratio of a reciprocating compressor varies according to the conditions under which the compressor operates. The compression ratio, defined as the ratio of the volume of gas at the intake to the volume at the discharge, is influenced by factors such as changes in suction pressure, discharge pressure, and the volume of the gas being compressed.

In practical applications, when the operating conditions of a reciprocating compressor change—such as variations in temperature, pressure, or flow rate—the compression ratio will adjust accordingly to accommodate those changes. This variability is crucial for maintaining optimal efficiency and performance within the compressor system.

The other statements lack accuracy. While some may suggest stability or fixed relationships, the real-world operation of reciprocating compressors shows that the compression ratio is indeed dynamic and depends largely on specific operational conditions.