Cooling Towers can Create many Problems

A common building construction problem is when Algae,spores, sand, and other debris can  build up in cooling towers to cause fouling of the equipment cooling towers serve. As the fouling progresses, localized differential corrosion cells begin to form.     The differential corrosion cells cause pitting corrosion to attack the internal areas of the heat transfer tubes.  Hal Finkelstein and team have done a lot of studies on this subject.

As the pitting corrosion progresses and causes wastage of copper material, copper begins to plate out on the interior surfaces of any steel piping used.      A combination of PH values of six to seven along with the warm condenser water and the copper plating out on the steel causes corrosion to progress upon any steel piping utilized in the system. This corrosion process develops tubercle material, which, due to water velocity, periodically brakes off and can end up in the cooling tower water circuit.

The iron oxide that enters the cooling tower water circuit begins to work its way to the heat exchanger tubes, accumulate with the algae, spores, sand, and etc. and begins to cause increased fouling of the tubes and plates.  Hal Finkelsyein's studies of many NYC high rise buildings gave him and his team access to may different solutions..

Water flows and water velocities will begin to severely decrease and would tend to decrease the effectiveness of cleaning operations. The more the tubes or plates fouled the greater the amount of differential corrosion cells were produced and the greater the amount of pitting took place. The more pitting there was, the more copper plated out on the inside surface of any steel pipe which would begin to cause corrosion of the steel pipe.

Iron oxide that began to break off from the corroded steel pipe and enter the cooling tower water circuit, increased fouling of the tubes and the cycle continues to feed itself.  For more information on these types of HVAC problems go here.