Technology to Boost Chiller and Cooling Tower Efficiency

As you know, your facility's cooling tower and chillers play critical roles in keeping the building at a proper temperature and ensuring that occupants are comfortable and productive. To accomplish that, this equipment needs to operate efficiently and reliably. However, without proper maintenance and cleaning, it will run less efficiently, which will increase energy use and boost operating costs. It also will be more vulnerable to downtime.

The importance of proper maintenance is a result of the way in which cooling equipment works. To start the process, water is pumped to the top of the cooling tower while outside air is forced through the tower at the same time. The water drops through a "fill" medium, which helps to expose as much of the water's surface as possible. As the water moves through the fill, it partially evaporates, and in the process, cools off and drops to bottom of the tower. From there, it heads to one or more chillers.

In the chiller, the water absorbs heat from a refrigerant as it travels through it. The refrigerant then moves into the air conditioning system to cool the building, while the water returns to the cooling tower. From there, the process starts all over.

The Contamination Problem

At several steps throughout this process, the cooling tower and chillers are vulnerable to possible contamination. For starters, if the air that is pumped into the cooling tower is dirty - perhaps from a nearby construction site or other source of contamination - it can leave deposits on the inside of the tower, as well as on the fill that the water travels through.

Not surprisingly, the dirtier the inside of the tower is, the dirtier the water that moves through it will be. "If the tower is clean, it helps keep the chiller clean," says Steve Spielmann, technology manager with Goodway Technologies Corporation, Stamford, Conn.

The contaminants in the air also can affect the water that moves into the chillers. There, the contaminants can drop from the water and adhere to the inside walls of the chiller tubes. As deposits build up on the chiller's tube walls, the motor is forced to work harder to maintain the same heat transfer as it does when it's clean, says Spielmann. In fact, it isn't unusual for dirty chillers to consume ten percent more energy just to operate, he adds. In addition, the extra strain on the motor could lead to having to replace it more quickly than would otherwise be the case.

Antiquated Maintenance Methods
Fraught with Challenges

Until the past few years, however, the only method available to clean cooling towers and chillers required first draining them, which meant wasting all the water that was already inside them. What's more, the draining process generally had to take place during off-hours, when the building wasn't occupied and the AC system could be shut down. While this avoided disturbing occupants, it usually meant incurring overtime costs.

Once the tower was drained, maintenance workers would crawl inside to scrub it with a mixture of harsh chemicals, shovels and scrub brushes. The job was dirty and time-consuming, and left maintenance workers exposed to the bacteria and scum lurking within the chillers and tower, which could be a breeding ground for Legionnaires' and other diseases. On top of that, the chemicals used in the cleaning process could negatively affect the quality of air within the building.

Even after the cleaning was complete, workers still had to refill the tower. Altogether, it wasn't unusual for the process to take four workers an entire workday to complete.

Not surprisingly, maintenance workers tended to put off this very unpleasant chore. Of course, that just made it more difficult when they finally did schedule it.

Technology to the Rescue

Fortunately, the tools available to clean cooling towers and chillers have advanced significantly over the past few years. Goodway's cooling tower vacuum system, the TowerVac™, lets workers clean the cooling tower without draining it and without immersing themselves in a hazardous environment. Instead, the powerful vacuum removes contaminants from the tower, even while it's filled and operating. This is quicker, reduces both overtime and water waste, and avoids the need for workers to handle harsh cleaning chemicals.

Similarly, Goodway's system for cleaning chillers, the Ream-A-Matic®, significantly streamlines and eases the job. The device incorporates a cleaning tool attached to the tip of a flexible shaft. As it snakes through the chiller's tubes, water from the cleaner flushes out deposits as they're loosened. That means the tube is cleaned and flushed in one operation.

What's more, the investment required to implement the equipment typically is in the range of several thousand dollars. While not cheap, the investment can be quickly recouped through just the labor savings. An added advantage: because a clean chiller motor runs more easily and efficiently, it's likely to last longer.

Given that these solutions make the jobs of maintaining clean coolers and chillers less difficult, maintenance personnel are more likely to adhere to a regular schedule of cleaning. For most facilities, twice-yearly cleaning will suffice. Facilities that are located in areas with greater pollution may require more frequent cleaning.

Fortunately, no matter what the schedule, the task of cleaning cooling towers and chillers now is safer, easier and quicker to complete with Goodway's technologies. "In terms of cooling tower and chiller cleaning, we've set the standard," Spielmann says. "This is the accepted way of cleaning."