A process chiller is the single largest energy using component in most industrial facilities. In many facilities, more than 50 percent of the annual electricity is consumed by a process chiller. Proper operation and maintenance of a chiller should always be a high priority in your energy management program. There are many factors that can contribute to decreased chiller efficiency. Below we take a look at the five most common chiller malfunctioning factors.

Poor Operation:

Poor operation of a chiller can not only decrease chiller efficiency, but can also decrease a chiller’s lifespan. A chiller can be damaged by trying to force it to do something it is not designed to do, and not understanding the negative effect certain applications can have on a chiller. The problem with poor operating practices is that their impact on chiller operation generally goes unnoticed. Chillers continue to operate well, but one day a minor chiller operational problem will become much bigger and unable to hide anymore. For example, the chiller might not be able to satisfy a cooling load that previously had never been a problem. When an instance like this occurs, technicians usually will blame the chiller itself and not realize the problem is caused from poor operation.

Ignored Maintenance:

Everyone knows good maintenance practices are important to the efficient operation of all building equipment; this is not any different for process chillers. If chiller maintenance is ignored for some time, it would not be surprising to find that the full-load efficiency of the machine has decreased. Poorly maintained chillers will use 20-25 percent more energy annually to produce the same cooling as a well maintained chiller. The key to good chiller maintenance begins with keeping a operating log. Recording chiller operating parameters regularly can provide maintenance personnel with a valuable diagnostic tool. Most chiller problems develop slowly over time. By tracking chiller data and reviewing it regularly, operators can identify trends in chiller performance, helping maintenance personnel pinpoint the underlying cause. Another important tool in chiller maintenance is keeping up with regularly scheduled maintenance inspections. Routine maintenance should be performed daily, weekly, or monthly to keep up with the operating efficiency of the chiller.

Ignoring Cooling Towers:

Cooling towers are important parts to the efficient operation of chiller systems. Cooling towers determine the operating efficiency of the chiller. Towers that are in good condition and well maintained will allow chillers to operate at peak efficiency.

Cooling towers are often exposed to things such as dirt, leaves and other debris which can clog air and water passages. Buildup of debris in a cooling tower can clog spray nozzles and water passages.


Proper sizing of a chiller is important to its efficiency. If chiller efficiency seems to drop quickly with decreasing load, most likely the chiller was oversized when purchased. Upgrades and changes to a facility as time goes on will often result in the number of decreases in cooling loads. As cooling loads decrease, the number of hours each year that a chiller operates at reduced load can decrease in its annual operating efficiency.

Ignoring Alternative Fuel Chillers:

If an old chiller was an electric-drive centrifugal unit, most likely the plant manager will replace it with a new electric-drive centrifugal unit when the old one has run out.

While the type of chiller installed 15 to 20 years ago might have made sense then, too many conditions have changed over the years. A plant manager should never assume that the same type of chiller is automatically the best choice for the facility today. New technology chillers, including natural-gas driven centrifugal chillers and steam or gas-fired absorption units, allow managers to use alternative fuels during times when electricity costs are high. By investigating the cost new generation chillers and their impact on operating costs, managers can gain significant savings in energy costs without sacrificing either performance or reliability. It is very important to be aware of these top five common threats to chiller efficiency. Just a few simple steps can help managers improve the performance of their chiller systems while improving the organization’s bottom line. For more information on chiller maintenance, visit our website at chillerservicenorthwest.com