Chillers require a large capital investment and are often the leading energy consumer in many businesses. As such, any steps that can be taken to improve energy efficiency and increase reliability should be readily received and implemented. This article discusses three such practices that should form part of your comprehensive maintenance schedule.
1. Ensure thorough water treatment
Water is used in most chillers to facilitate heat transfer. It should be treated properly to ensure no biological growth, scaling or corrosion. Closed-water systems, such as chilled-water systems leading to the evaporator, require a single chemical treatment in the beginning. Open systems, such as condenser-water systems leading to the condenser, should be subjected to continuous chemical treatment.
It is important to choose the right vendor for chemical treatment, one who understands challenges of the local water supply and can offer full-service treatment of all water systems within your facility. If you notice scale buildup within your condenser or evaporator systems, it means that your water isn't being properly treated. The vendor should be available to test the waters at least quarterly (more often for problematic water sources) and institute the right treatment program as well as cleaning out scale-ridden tubes in the chiller.
2. Clean filters and strainers
System strainers, side-stream filters and sand filters should also be cleaned at least bi-annually. If you notice pressure dropping at the filters (even before six months are up), you need to clean them. You can also refer to the manufacturer's manual for recommendations on cleaning frequency. Keeping filters and strainers clean will reduce incidence of erosion in chiller tubes as a result of small particles travelling at high speeds. Such erosion causes pitting in the tubes and reduces efficiency of heat transfer. If left unchecked, tubes may eventually plug and even fail, which is very expensive to repair. Planned annual outages should be scheduled during which time technicians inspect chiller tubes for signs of erosion, corrosion and scale buildup.
3. Schedule oil and refrigerant analysis
Part of the annual maintenance schedule should include refrigerant and oil analysis for signs of contamination. Usually, you'll contract a vendor to carry out spectrometric analysis to identify chemical contaminants such as acids, metals and moisture, all of which reduce performance efficiency. The vendor should be qualified in equipment testing. Check with your manufacturer whether they provide analysis services.
The oil sample should be taken while the chiller is running. Oil change should only be done if testing reveals necessity. It is also important to monitor pressure at oil filters and change them when pressure drops outside the tolerable levels (check the manual for this). Oil analysis may also shed light on other faults within the chiller. For instance, high moisture content in oil may indicate issues with your purge unit. Finally, check refrigerant for oil contamination, which can significantly reduce refrigerant performance.
Get in touch with a company like Maximus Chillers if you do find you need chiller repairs.