Which pairing correctly matches the cooling device with its location in a multi-stage compressor?

• A. Intercooler cools gas between stages; Aftercooler cools gas after the final stage.
• B. Intercooler cools gas after the final stage; Aftercooler cools gas between stages.
• C. Intercooler heats gas between stages; Aftercooler cools gas after final stage.
• D. Intercooler removes moisture; Aftercooler adds heat.

Answer: (A)

Cooling in a multistage compressor is about keeping temperatures in check to make the process efficient and protect the equipment. The intercooler sits between the compression stages, removing heat from the gas before it goes into the next stage. By cooling between stages, the next stage doesn’t have to work as hard, which lowers overall power consumption and reduces thermal stress on the compressors. After the final stage, the remaining heat is removed by the aftercooler, bringing the discharge gas down to a safer, workable temperature for downstream equipment and for moisture handling downstream. The intercooler isn’t primarily for moisture removal, and it doesn’t heat the gas. The aftercooler cools after the last stage, not between stages, and isn’t intended to add heat.