Air Blast After Coolers
An airblast after cooler works (& looks like) a radiator by exchanging heat between the compressed air to the ambient air. A correctly sized and operating after cooler reduces the temperature of the compressed air to within approximately 10°C of the ambient temperature (if the temperature surrounding the after cooler is 30°C, the after cooler will drop the compressed air temperature to within 40°C).
This after cooler is a relatively low maintenance item but care must be taken in keeping the fins free of dirt build-up. The fan motor requires an electrical power supply but some after coolers are available with pneumatically driven fan motors.