As many facility management departments and HVAC service providers begin shutting off chillers for the winter season, it is important to recognize the importance of chiller maintenance. This part of winter maintenance may seem overwhelming, expensive, and lower on the list of priorities while prepping your facility for the cold months ahead, but if you’re thinking about skipping HVAC maintenance item this year, you may want to reconsider.
“Spending the time to proactively clean and maintain your chiller in the Fall can prevent headaches and provide better results when you go to start it back up in the spring,” says Tim Kane, President of Goodway Technologies, provider of HVAC maintenance solutions based in Stamford, CT. “It also gives facility managers the opportunity to identify any issues or problems that can be fixed in the off-season.”
Chiller tubes are susceptible to the buildup of scale and other sediments and residue, including mud, slime, sludge, and algae. These inefficiencies can have a big impact on the bottom line. The U.S. Department of Energy estimates chillers are expending up to an additional 30% in energy through inefficiencies and recommends that certain chiller maintenance operations be done at least once a year, including both cleaning and Eddy current testing of condenser and evaporator tubes.
Here are some tips from Goodway on executing a chiller maintenance program.
Right Equipment Makes The Job Easier
Water treatment alone will not keep tubes clean. Even the smallest amount of scale can lower chiller efficiencies. Regular cleaning and inspections should be implemented in conjunction with water treatment. Research the options to find which equipment will provide a solution for your chiller maintenance needs, and meet your budget.
There are portable tools that HVAC service teams can use to help perform the optimum chiller cleaning. These include:
Rotary Tube Cleaner. Ideal for cleaning the tubes, these units feed water to a rotating cleaning brush or tool, flushing out deposits as they are loosened. Newer, specialized rotary tube cleaners can deploy corrosion inhibitors and antimicrobials while brushing is in effect. Electric and air power models are available.
Chemical Descaler. Chemical descalers are effective in dissolving calcium, lime, rust, and other types of deposits from passages that come into contact with water. Make sure to review the label to see what base metals the descaler can be used with to reduce the risk of damage
Brushes. Attaching brushes to the tube cleaner can help remove soft and light scale deposits. While brushes are required for any tube cleaning, it’s important to understand which substances are building up inside the tubes to select the correct type of brush. For example, a light to medium buildup that occurs with algae, mud, or slime requires a different brush than a crustier buildup from scale and other mineral deposits.
5 Steps To A Chiller Maintenance Plan
A chiller maintenance plan or checklist is an ideal way to proactively stay on track and make sure this equipment is running efficiently and properly. Pull together a team of individuals involved with performing facility maintenance, and discuss what steps should be taken to reach optimal performance.
Step 1: Maintain a Daily Operating Log. The Federal Energy Management Program (FEMP) recommends updating the log four times a day to monitor key operating parameters that will help indicate if any problems are developing while also measuring efficiency gains.
Step 2: Keep Tubes Clean. Fouling and scale can reduce efficiency. Regular monitoring can help recognize when tube cleaning should take place, however it is recommended at least once a year. Pressure loss can also indicate tube corrosion.
Step 3: Ensure a Leak-Free Unit. Leaks can affect the operation of the system and release hazardous refrigerants.
Step 4: Sustain Proper Water Treatment. Failure to perform chiller maintenance can also affect water quality. It does not take much fouling or scale buildup to start impacting the efficiency of your system. Keep a close eye on water treatment and chemistry.
Step 5: Analyze Oil and Refrigerant. Refrigerant levels should stay within the manufacturer’s recommended levels. An air-purge timer (increases in air-purge time may indicate a leak), checking the refrigerant sight-glass for bubbles and checking at all joints and connections with a gas analyzer are all ways to help track refrigerant levels.
Don’t Forget The Cooling Towers
Chiller systems are one of the more complex pieces of equipment in a plant or facility, so it’s worth making the investment to take care of it. A cooling tower’s performance has a direct link to chiller efficiency. In fact, for each degree that condenser supply temperature is above design specifications, chiller efficiency is reduced by 2%.
When left unmaintained, the warm water in cooling towers can promote algae growth, and flash evaporation can produce hard scale deposits or calcium fouling. Cooling tower fill acts a massive air scrubber, encountering dust, pollen, and insects, which contribute to bacteria growth. This creates a breeding ground for diseases such as Legionella. Like chillers, regularly cleaning cooling towers can decrease the chances of equipment corrosion or breakdowns and can increase plant efficiency.