AAF has long recognized the need for a new type of gas cooling device, one that not only cools process gases, but one that could be designed to recover the heat to be used in other processes. It was with these objectives that AAF developed the Forced Air Cooler (FAC), or air to air heat exchanger, and now has over 50 of them installed worldwide, either operating or under construction.

The FAC can be used for cooling kiln or preheater gas and clinker cooler gas. It has several advantages over conventional methods of cooling by U-tube coolers, water spray towers, and cooling by dilution air.

The FAC is compact and can be fitted into spaces where a U-tube cooler will not. It can be designed to maintain a constant outlet temperature, independent of the ambient air temperature. It cools the gas without adding to the volume, unlike dilution cooling and water spray cooling. The tube bundle section can be shipped in one piece, thereby reducing field installation costs.

A thermocouple mounted in the FAC outlet duct controls the fans as required to maintain a constant outlet temperature. Several different duct arrangements are available, including top entry, bottom entry, and side entry.