Aftercoolers Resource Page
Aftercoolers – Shop with Industrial Service Solutions
Reliable Cooling. Cleaner Air. Protected Equipment.
Hot compressed air is full of vapor. As it cools, that vapor condenses into water — introducing gallons of liquid into your system every day. Without an aftercooler, a 200 scfm compressor operating at 100 psi can release 45 gallons of water dailyinto your compressed air lines.
Aftercoolers are essential.By cooling compressed air immediately after discharge, they condense and remove up to 75% of moisture, reducing downstream problems and protecting your investment.
Why Is Aftercooling Required?
Compressed air discharged from compressors is extremely hot (see “Compressor Outlet Temperatures” below). At these temperatures, air contains large amounts of water vapor. As the air cools, the vapor condenses into liquid. Without an aftercooler, that liquid ends up in your piping, dryers, tools, and equipment.
Additionally, reducing air temperature helps:
Form condensate that can be removed
Increase capacity and efficiency
Protect equipment from heat damage
A moisture separatorinstalled at the discharge of the aftercooler removes most liquid and solids using centrifugal force, while an automatic drain clears collected condensate.
Compressor Outlet Temperatures
| Type of Compressor | Avg. Outlet Air Temp (°F) | Avg. Outlet Air Temp (°C) |
|---|---|---|
| Oil Flooded Rotary | 200 | 93.3 |
| Oil Free Rotary | 350 | 176.6 |
| 2-Stage Reciprocating | 300 | 148.8 |
| Centrifugal | 225 | 107.2 |
(This corresponds to “Figure AC1-1” in your documentation.)
Functions of Compressed Air Aftercoolers
Cool hot compressed air discharged from compressors
Reduce fire risk from overheated piping
Lower compressed air moisture content
Increase system capacity
Protect downstream dryers, filters, and equipment
Coolers are typically sized with a CTD (Cold Temperature Difference) of 5°F to 20°F (2.7°C to 11°C), meaning outlet temperature equals cooling medium + CTD.
Recommended Location:
Aftercoolers should be placed as close as possible to the compressor discharge.
Types of Aftercoolers You’ll Find
Air-Cooled Aftercoolers
Use ambient air to cool compressed air. Air passes through finned tubes or corrugated aluminum sheets while a fan forces ambient air across.
Check out the [Air-Cooled Aftercoolers]page: eIndustrialSolutions’ collection.
Example model: Van Air Systems AC-100-5 Air-Cooled Aftercooler
Belt Guard Air-Cooled Aftercooler:
Mounts directly to the compressor’s v-belt guard. The compressor pulley fins force air over the aftercooler and compressor, ensuring proper operating temperature.
Water-Cooled Aftercoolers
Most common design: Shell & Tube Heat Exchanger. Compressed air flows through tubes, water flows on the shell side in counterflow. Heat transfers from air to water; vapor condenses, then removed by moisture separator and drain valve.
Example: Quincy 22709-21 Heat Exchanger, Aftercooler (Water-Cooled)
Another: Kellogg K0159221 Water Cooled Aftercooler (OEM)
Advantages include high heat transfer and no electrical consumption. Disadvantages: water usage and maintenance.
Aftercooler Sizing & Selection
Size to cool air within 5°F to 20°F (2.7°C to 11°C)of ambient or cooling water (approach temperature).
Always plan for the hottest day at 100% relative humidity.
Typical air exit temps: 180°F to 350°F (82.2°C to 176.6°C).
Oversizing often pays off — cooler air, reduced dryer burden, lower pressure drop.
Aim for 1–2 psi pressure dropacross the aftercooler in good design.
Compressed Air System Component Temp Requirements
| Component | Normal Temp (°F) | Normal Temp (°C) | Max Temp (°F) | Max Temp (°C) |
|---|---|---|---|---|
| Standard Refrigerated Air Dryer | 100 | 37.7 | 130 | 54.4 |
| High Temp Refrigerated Air Dryer | 180 | 82.2 | 190 | 87.7 |
| Heated Desiccant Dryer | 100 | 37.7 | 120 | 48.8 |
| Heated Compression Desiccant Dryer | 350 | 176.6 | 375 | 190.5 |
| Pressure Swing Desiccant Dryer | 100 | 37.7 | 120 | 48.8 |
| Standard Particulate Filter | 100 | 37.7 | 150 | 65.5 |
| High Temp Particulate Filter | 350 | 176.6 | 450 | 232.2 |
| Coalescer Filter | 100 | 37.7 | 150 | 65.5 |
| Vapor Filter (Activated Charcoal) | 100 | 37.7 | 150 | 65.5 |
| Oil / Water Separators (condensate) | 100 | 37.7 | 180 | 82.2 |
| Drain Valves | 100 | 37.7 | 180 | 82.2 |
| FRLs (polycarbonate bowl) | 100 | 37.7 | 125 | 51.6 |
| FRLs (metal bowl) | 100 | 37.7 | 175 | 79.4 |
(Matches your “Figure AC1-4” specs.)
Maintenance Requirements
Water-Cooled Aftercoolers:Inspect, clean, check approach temperature, check pressure drop, and monitor water quality.
Air-Cooled Aftercoolers:Inspect and clean regularly; check drain valves daily.
A dirty aftercooler leads to higher discharge temperature and increased pressure drop.
Rules of Thumb
Aim for 5°F to 20°F (2.7°C to 11°C)approach temperature.
Size for the worst-case ambient/humidity conditions.
Always install the aftercooler directly downstream of the compressor.
Oversize if feasible to reduce dryer load and pressure losses.
Every 20°F (≈11.1°C)rise in compressed air temp roughly doublesmoisture content.
Shop Aftercoolers on eIndustrialSolutions
Explore these product categories and examples:
Coolers & Heat Exchangers
Air-Cooled Aftercoolers
Van Air Systems AC-100-5 Air-Cooled Aftercooler(example product) Industrial Service Solutions
Quincy 22709-21 Heat Exchanger, Aftercooler (Water-Cooled)Industrial Service Solutions
Kellogg K0159221 Water Cooled Aftercooler (OEM)Industrial Service Solutions
Sullair 88290003-026 Aftercooler (OEM)Industrial Service Solutions
FS Curtis 2689510010 Air Cooled AftercoolerIndustrial Service Solutions
Ingersoll Rand 47752803001 Aftercooler, Pellets (OEM)Industrial Service Solutions
Start with the main category page above to filter by flow, approach, type, and mounting options.