What are aftercoolers?

• A. Cool gas after final stage.
• B. Cool gas between stages.
• C. Heat gas after compression.
• D. Filter gas contaminants.

Answer: (A)

Aftercoolers are heat exchangers placed after the final stage of compression. Their job is to shed the heat produced during compression and cool the gas to near ambient temperature. As the gas cools, moisture condenses and can be drained, which protects downstream equipment and improves dryer and filtration efficiency. This distinguishes them from intercoolers, which cool between stages, and from filters or other moisture-removal devices, which handle contaminants rather than just cooling.