Energy Savings for Buildings: Focus on Cooling Towers
With energy costs historically high, there are numerous ways that Facilities Departments can take steps for their cooling tower equipment to run as efficiently as possible. By maximizing the heat transfer capabilities, energy savings will be optimized leading to lower operational costs. Three ways to do this are the following: adding appropriate scale and corrosion inhibitors, adding appropriate biocides, and performing routine cleaning events.
Scale and Corrosion Inhibitors
Scale and corrosion inhibit cooling tower efficiency leading to higher energy costs. Proper treatment and documentation, combined with routine visual inspections, will lead to the desired outcome of better energy efficiency. Scale inhibitors work to prevent build-up of mineral deposits including, but not limited to, calcium carbonate and calcium phosphate. When these minerals precipitate on or are allowed to settle onto critical surfaces, heat transfer and water distribution capabilities suffer. Polymers and other dispersants/antiscalants prevent the formation of scales and other deposits by allowing the scaling constituents to remain in the water beyond their saturation points. They then become beneficial by providing an important part of the corrosion protection strategy. The dispersants also keep particulates properly suspended so they can be blown down rather than forming sedimentary deposits. Since cooling towers cool through evaporative cooling, proper distribution of the water within the tower is critical to maximizing evaporation. Mineral scale and other foulants can form in the tower fill leading to poor water distribution. Without proper corrosion control, rust flakes from tower materials can block distribution nozzles leading to poor water distribution. Corrosion additionally leads to overall degradation of expensive tower equipment. Monitoring chemical feed, performing routine visual inspections, and choosing the right type of chemical are all critical parts of a successful water treatment plan.
Slimes and algal mats greatly depress heat transfer in the same way that mineral scale does. A biocide treatment program will add a small amount of chemical to control bacteria which leads to biofilms and complex microbiological communities. Plant material sometimes makes its way into cooling towers competing with some biocides. In these cases, strainers may be additionally helpful to lessen outside contaminants from entering the system. Biocides also help with certain types of microbiologically induced corrosion and spread of disease such as Legionnaires’ disease. A proper biocide treatment program can be validated by taking total bacteria samples and Legionella bacteria samples.
In addition to a successful water treatment program, routine mechanical cleanings are integral to energy savings. Wearing the proper personal protective equipment, workers will enter the cooling tower and mechanically remove debris and sanitize surfaces. Many Facilities Departments choose to clean their towers both in Spring and Fall as recommended by the Occupational Safety & Health Administration (OSHA). Doing so will take enormous steps toward allowing water contact surfaces to be ready to transfer heat as intended.
Please reach out to Barclay Water Management, Inc. anytime for more Water Treatment information. Our Employee-Owned Company is dedicated to energy savings, and happy to provide as assessment of your current Cooling Tower Water Treatment program. We are committed to finding opportunities to maximize the life, efficiency, and reliability of your water systems.