10 Tips for Improving Chiller Operation & Efficiency

Conair’s Heat Transfer Team offers the following tips on how to make sure your chiller functions properly and efficiently.

1. Maintain Water Quality

Pure water is the best heat-transfer fluid there is. Anything that contaminates it will reduce its efficiency, so make sure that both process-cooling water and condenser water (on water-cooled chillers) stay clean. You may want to consult a local water treatment professional for advice on adding inhibitors that can minimize corrosion and plate-out of mineral salts. Weekly biocide treatment of cooling tower water may be advisable.

2. Flush Process Cooling and Condenser Lines

Periodically flush out your process cooling water to remove any bits of rust or other debris that can reduce cooling efficiency and damage pumps. Back-flush the water-cooled condenser with a dilute concentration of boric acid to help remove mineral plate-out on the inside of the condenser. After flushing, refill with high-quality water (see above re. Water Quality).

3. Check Strainers for Debris

Your chiller is equipped with strainers designed to filter out debris in the system including both naturally occurring products of corrosion, etc., as well as debris that may have gotten into the system during start up. If the strainer becomes even partially blinded, power consumption will increase as the pumps work harder to maintain necessary flow rates. Access to screens is provided and they should be pulled periodically and cleaned.

4. Clean Air-Cooled Condenser

Dust, dirt and debris will reduce the efficiency of an air-cooled condenser, just as contamination affects a water-cooled unit. How often it needs to be cleaned will depend on your ambient conditions. A dusty location outdoors or where powders are being processed will demand more frequent attention. Special cleaning solutions are available, but generally it is sufficient to vacuum out the condenser and straighten any bent fins. Outdoor units should be power washed with a mild cleaning solution. Be sure to clean the screen on the air-intake side as well to prevent excessive compressor power consumption.

5. Check Refrigerant Charge

Chillers incorporate a totally sealed refrigerant system and loss of refrigerant is rarely an issue. However, if you notice your chiller is no longer cooling properly, check the refrigerant sight-glass. If you see mostly gas, this will indicate that your refrigerant level is low and you probably have a leak in the system (a broken pipe or seal). A certified refrigerant technician should be brought in to find the leak and repair it.

6. Check Pipe Supports

Any abnormal vibration of internal refrigerant pipes and components can cause a connection failure and leakage, so look occasionally at the internal piping during chiller operation. Make sure all lines are firmly supported and all vibration isolated.

7. Verify Reservoir Level

The process-water pump inlet in your chiller always needs to be flooded and water in the reservoir must be maintained at specified levels. Low levels can allow vortices to form and cause air to mix with water in the pump. Any air in the water will reduce cooling efficiency. Check these levels after every mold change or whenever process water has had an opportunity to leak out. An AutoFill option on your chiller can eliminate these potential problems.

8. Pull and Clean Temperature Sensors

Chiller temperature sensors can get dirty the same way the evaporators do. The resulting deposits reduce the responsiveness of the sensor. The chiller will continue to operate, but for peak performance, the sensors should be pulled, being careful not to damage the connecting wires. Wipe the sensors down with a clean cloth and replace.

9. AutoTune Your Chiller

If your chiller is equipped with an autotuning temperature controller, use it whenever you move the chiller from one application to another. This is especially important when the cooling load is substantially different. This will ensure the least possible deviation from setpoint temperature.

10. Check Electrical Connections

To prevent burning of contactors, short circuits and/or loss of power within the system, periodically check all electrical connections. To do this, turn off and lock out the main power to make the chiller safe to work on. Then check that all contactor screws are tight and that all wire terminations are firmly seated in the terminals and making solid contact. If you see any burned or abraded insulation, replace the damaged wire.

For more information, call the New Product Hotline at 1-888-486-6601

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