Broken Cooling Tower Fan Blades

When a cooling tower fan blade breaks it can create significant damage and/or injury. When one blade breaks it puts the fan out of balance. The combination of high speed and lack of balance can cause other blades to break, the shaft to bend, and/or gear box damage. The broken blades in the picture came out of a 500 ton tower installed at grade level. Both blades broke and shot out through the side of the fan shroud. Fortunately, there were no personnel in the area at the time of the failure.

Griswold SBC Non Chemical Water Treatment Device

Here is a picture of an installed Griswold SBC Non Chemical Device (NCD) for water treatment. It is claimed to prevent scale and eliminate biofilm in cooling towers and closed loops. Traditional water treatment chemistry is still being utilized to treat the system. The system volume is 65,000 gallons with a constant 42 gpm make up rate.

The unit claims to treat the water through "electronic resonance". The advertising brochure claims that the treatment chamber "uses less energy that a standard 100 W light bulb". Who in the scientific community can explain how there is enough energy to perform the tasks this unit claims it can do? If you choose to defend the unit please list your credentials.

Wasted Resources

During a recent central plant survey I came across these boiler blowdown controllers. Both were controlling on line boilers with similar run time, load, and make up water characteristics. The controller on the right is in alarm due to low conductivity. Unfortunately, the plant operator hadn't noticed the alarm. No corrective action was taken. Running the boiler in this condition is costly. It wastes water, chemical, and electricity. The water treatment cost associated with running a poorly controlled boiler can easily be double the cost of running a similar program with good controls. If you find that your water, chemical, and electrical costs have suddenly increased it may be time to revisit the control parameters of your water treatment program.

Chemical Induced Corrosion

The nipple in this condenser water return line is experiencing severe corrosion. The cause of this corrosion is chemical. Rather then feed chemical through an injection quill an attempt was made to feed directly into an existing valve. Feeding chemical in this manner can be very harsh on the surrounding metallurgy. Although this was a quick and cheap install the long term reliability of the system has been compromised.

Non Chemical Water Treatment Device

I recently had the opportunity to see the conversion of a cooling tower from standard chemical water treatment to a new "Non Chemical Water Treatment Device". In this instance the unit installed was called a Fluidtron. These pictures were taken at about 90 days into the non chemical water treatment program. While the algae build up is troubling it is a minor problem compared to the aggressive corrosion cells that developed. The customer ended up re-coating the tower basin with an epoxy and installed brominators to add Bromine to control the algae.

A quick search of vendors selling this product uncovered some marketing literature. One brochure stated that the unit "eliminates the need for chemical treatment" and listed the benefit of "extended life of equipment" because "reduced corrosion rates extend equipment life". Certainly one case study does not reveal enough data to draw a conclusion, however, in my opinion the results achieved here border on negligence.

I am not implying that all non chemical water treatment devices do not work but the end user should to do their homework before making an investment in a "new" system that is designed to protect the heart of a buildings HVAC system.

Cooling Tower Frozen Over

A unexpected cold snap hit recently and created some problems for this cooling tower. It was was not drained and froze over. It is not apparent whether or not there was any damage to the tower or the fill. For towers that are operated in climates that may experience freezing temperatures be sure that the sumps are drained or that the sump heaters are on and operating correctly when the temperature begins to drop.

Non Oxidizing Microbiocide

Non Oxidizing Microbiocides (NOM) have a specific mode of operation. Some attack structural, or functional components of protoplasm such as enzymes, proteins, lipids, metals, or minerals. Some NOM poison or interfere with the normal metabolic process. Still others inhibit the permeability of the cell membrane. All of these modes contribute to the death of the cell body.

Regardless of the the mode, all NOM have the same general effects upon the system.

1. In the presence of a toxic substance mircorbiological organisms increase their rate of metabolism. This is part of their nartural survival response. This means that underfeeding a biocide will actually stimulate the microbiological growth in the system.

2. The microbiological population in a cooling tower can be drastically altered through the use of only one NOM. Species and strains of microbiological organisms least affected by the biocide will some become the dominant strain in the system.

3. NOM kill, but they do not consume the organic molecules that previously supported the life of microbes. The debris of the dead cells provides a significant source of food for new growth. This tends to cause a response of higher growth and reproduction rates. This is one of the main reasons an oxidizer is often used in conjunction with NOM. Oxidizers physically destroy the organics eliminating the food source.

4. Microbiological organisms rapidly adapt to a changing environment. The organisms will develop resistant strains.