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Quotes - Engineering - SalesCompressed Air Aftercooling
An aftercooler is a heat exchanger with one job: take the heat of compression out of the air before it goes anywhere else.
Air leaving a two-stage rotary screw compressor is around 250°F; from a single-stage reciprocating machine it can be 350°F. At those temperatures the air holds all the water vapour it drew in, and as it cools in the piping that water condenses in the worst possible places. An aftercooler brings the temperature down immediately, in a vessel with a drain, so the water condenses there instead. At 100 PSIG and 250°F inlet, 1,000 SCFM carries well over 30 gallons of water a day - an IPAC aftercooler and separator remove the great majority of it before the receiver.
Rotary Screw
Reciprocating
Centrifugal
Ahead of Dryers
Air-Cooled or Water-Cooled?
A quick way to decide.
Checklist
- No cooling water, or water is expensive: A Series
- Water available, shop air duty: 51 Series
- Water available, air feeds a dryer or a process: 59 Series
- Compressor over 700 HP or above 2,800 SCFM: water-cooled
IPAC Ranges
- Air-Cooled Aftercoolers — Fifteen catalogued sizes from 30 to 2,800 SCFM, matched to compressors from 5 to 700 horsepower
- Water-Cooled 51 Series — Fifteen shell and tube models from 38 to 4,785 SCFM, all 51-1/8 inches long
- Water-Cooled 59 Series — Nineteen close-approach models from 37 to 11,970 SCFM, all 59 inches long
| RANGE | TYPE | COVERS | RATING | PART NUMBERS |
| Air-Cooled Aftercoolers | Air-Cooled Aftercooler | Fifteen catalogued sizes from 30 to 2,800 SCFM, matched to compressors from 5 to 700 horsepower | 200 PSIG / 400°F | 15 |
| Water-Cooled 51 Series | Water-Cooled Aftercooler | Fifteen shell and tube models from 38 to 4,785 SCFM, all 51-1/8 inches long | 200 PSIG (300 PSIG small NPT units) | 15 |
| Water-Cooled 59 Series | Water-Cooled Aftercooler | Nineteen close-approach models from 37 to 11,970 SCFM, all 59 inches long | 200 PSIG (300 PSIG small NPT units) | 19 |
More About Compressed Air Aftercooling
Air-Cooled or Water-Cooled
The choice between air-cooled and water-cooled is usually made by the plant. The A Series air-cooled unit needs only a power connection and delivers air within 15°F of the room temperature, which is enough for most shop air. Where cooling water is available, the 51 Series shell and tube unit reaches 15 to 20°F above the water temperature, and the 59 Series 5 to 10°F - cooler outlet air, less water left in vapour form, and an easier life for the dryer that follows.
The Separator Is Not Optional
Whichever range is chosen, the separator is not optional. The aftercooler condenses the water into a fine mist that the air carries with it; without a separator directly downstream, the mist simply re-evaporates or collects further down the line.
Related
SERIES • AFTERCOOLER
Air-Cooled Aftercoolers
Fifteen catalogued sizes from 30 to 2,800 SCFM, matched to compressors from 5 to 700 horsepower.
+ Learn More
SERIES • AFTERCOOLER
Water-Cooled 51 Series
Fifteen shell and tube models from 38 to 4,785 SCFM, all 51-1/8 inches long.
+ Learn More
SERIES • AFTERCOOLER
Water-Cooled 59 Series
Nineteen close-approach models from 37 to 11,970 SCFM, all 59 inches long.
+ Learn MoreCommon FAQs
Most of it. At 100 PSIG and 250°F inlet, 1,000 SCFM carries well over 30 gallons of water a day as vapour; cooled to within 15°F of 80°F water, roughly two-thirds of it condenses and is caught by the separator. The rest leaves as saturated vapour for the dryer.
Often, if the plant can accept air within 15°F of room temperature rather than within 5 to 20°F of the water. Match on SCFM and pressure class, allow for the fan motor supply, and check that the A Series footprint and connections fit. Above 2,800 SCFM the answer is water-cooled.
Before, directly at the compressor discharge, with the separator immediately after it. Cooling the air before the receiver keeps the condensate out of the tank and lets the receiver act as a second settling stage rather than the first.
