Air/Water Aftercoolers
Water-cooled shell-and-tube aftercoolers provide an easy and efficient solution for cooling compressed air. The counter-current heat exchanger design enables the compressed air temperature to be lowered to the required level, helping to optimise downstream processes. This is particularly important for adsorption dryers, which operate best with moderate inlet temperatures—conditions that can be reliably achieved with the GDWA range. The resulting air temperature remains slightly above the cooling water temperature.
Since compressed air typically contains moisture, the cooling process causes condensate to form. This condensate can be removed using a separator installed at the aftercooler outlet. In models up to GDWA350, the integrated separator features an aluminium body with a cyclone cartridge and is equipped with an automatic, float-operated condensate drain. From model A450 onwards, separators are constructed with a carbon steel body and a cyclone separator with a manual drain. Optional reduction fittings are available to facilitate connection to the compressed air system
Design Conditions
- The maximum compressed air inlet temperature is 200 °C
- The maximum allowable compressed air pressure is 16 bar
- The maximum water inlet temperature is 90 °C
- Maximum water pressure of 10 bar
- The minimum ambient operating temperature is 1 °C
Operating principle
Within the heat exchanger, compressed air flows through stainless steel tubes surrounded by cold water on the shell side. The cooling water moves in a counter‑current direction and is guided by internal baffles, which increase turbulence and enhance the heat transfer coefficient.
The GDWA range is designed with optimised exchanger sizing, ensuring low pressure drop on the compressed air side while maintaining excellent thermal efficiency. At the tube outlet, a cyclone separator generates a swirling airflow that effectively separates condensate from the compressed air, allowing the liquid to drain away by gravity.
