There is a remarkably broad definition of the term fouling. It mostly describes any kind of deposit that appears upon the heat exchanger’s surface, making it function improperly. Usually, manufacturers make provisions for fouling in the design of their product, allowing the heat exchanger to function within normal parameters even though the pipes are not clean.
There are several types of fouling, such as sedimentation fouling, chemical reaction fouling or corrosion fouling. Each of them is harmful in its own way to the heat exchanger. Sedimentation occurs especially in cooling systems. Water contains suspended solids that settle upon the heat exchanger’s surface. Chemical fouling consists mainly of thermal degradation of components due to excessive temperatures or pressure.
The most feared fouling is corrosion fouling, since it will permanently damage the heat exchanger and significantly reduce its lifespan. The solution against corrosion is the material used in manufacturing the heat exchangers. Nickel and chromium alloys, copper and stainless steel are the most popular materials used due to their resistance to corrosion and oxidization. Rarely biological fouling occurs. This means that microorganism in the water have attached themselves to the surface of the heat exchanger.
