Scaling/Descaling on Chillers for Energy Optimization
Scale build up on chiller units can increase energy usage and drive up costs. After descaling, a power analyzer can detect if the unit has properly been descaled by monitoring its energy usage.
According to the U.S. Department of Energy, a scale of 1/32-inch thickness produced by low-pressure applications, leads to a two percent fuel loss. The U.S. Environmental Protection Agency states an example using a firetube boiler. 450,000 million British thermal units (MMBtu) of fuel at $8 per MMBtu over 8,000 hours per year, with a 1/32-inch thick scale build-up, spikes yearly operating costs by more than $70,000. In high-pressure applications where additional deposits exist, these losses can increase as high as seven percent.
In industry, two methods of descaling are used to remove the scale build up within chillers, electromagnetic and chemical. In chemical descaling operations, typically hydrochloric acid is flushed through the pipes to react with the alkaline carbonate compounds that have built up within them. Chemical descaling is expensive because it often requires a lot of logistics, safety precautions, and manpower. However, electromagnetic descaling is continuous, logistically simple, and safer. But even if an electromagnetic descaler is used, it only reduces the use of a chemical descaling operation by a significant margin; it doesn’t eliminate the need of chemical descaling altogether. Therefore, in modern descaling operations, it is important for the operators to learn when to apply the appropriate descaling agents. By continuously monitoring the efficiency of the electromagnetic descaler, it will be possible to decide precisely when it is needed to use the chemical process for descaling.