Chilled water plants are sophisticated assets comprised of mechanical and electrical systems controlled by programmable logic controllers (PLCs). They play a critical role in the operation of a wide range of facilities, including power plants, industrial facilities and data centers, and are often designed to function with minimal operator interaction. However, even the most intelligent systems degrade over time and require some amount of service and tuning to maintain optimal performance.
Here are some preventative maintenance measures you can take to ensure that your chilled water system is always operating in an efficient, safe and reliable manner while maintaining peak performance.
- Monitor and control cooling tower water chemistry – Regular monitoring of water chemistry, including pH, alkalinity, hardness, and conductivity, should be performed to proactively identify the potential onset of water quality issues such as corrosion, fouling, scale, and microbiological contamination. Allowing these water quality issues to proliferate can have a significant impact on cooling system performance and efficiency. When a problem is identified, a comprehensive water treatment program should be implemented to address it. Because water quality varies depending on location, there is no universal program that applies to all cooling systems. The optimal course of treatment will depend on a number of factors, including water availability, the quality of water being used for cooling, and the design of the cooling system itself (open, once-through, or closed, for example). Chiller manufacturers’ recommendations for water quality must also be taken into account when monitoring the cooling tower chemistry.
- Maintain instrumentation calibration – Routine calibration is critical to the optimal operation of any mechanical or electrical system. In addition to ensuring that parameters such as flow, temperature and pressure do not deviate from safe and acceptable ranges — which can lead to costly equipment breakdowns — accuracy of measurement is essential to maintaining process visibility. Because the accuracy of even the most rugged devices will inevitably degrade over time, calibration should be performed regularly (monthly, quarterly, etc.). It may also be required after the occurrence of an abnormal process event. In every case, technicians should perform calibrations in accordance with manufacturer recommendations.
- Brush condenser tubes annually – The plant’s system performance is directly affected by the chiller’s ability to transfer heat. When condenser tubes become fouled or contaminated with mud, algae or scale, heat transfer efficiency deteriorates, causing the chiller to work harder to meet the cooling demand. This in turn increases power consumption and energy costs. With pumps working harder, maintenance requirements can also increase. To avoid contamination and/or build-up on heat transfer surfaces, condenser tubes should be mechanically brushed typically once per year. Instituting and following a water treatment program will also help keep tubes from scaling quickly, and monitoring pressure drops across the condenser will alert technicians when scaling is becoming an issue.
- Inspect balancing valve positions – Balancing valves serve a number of functions in cooling systems. Most importantly, they are responsible for maintaining differential pressure (i.e., hydronic control). In an unbalanced system, flow rate to individual heat exchangers will deviate from design specifications, leading to an inability of the system to meet cooling demand. Inspection of balancing valves should be conducted periodically to avoid these issues, particularly in systems with valves that must be balanced manually.
- Perform system health checks – Periodically conducting system health checks is important to ensure that cooling systems are in good working order. In addition to helping identify defects and inefficiencies, conducting these checks provides operators with the opportunity to see how mechanical and electrical systems are performing relative to their original startup. As data is logged over time, a history of operating conditions can be established. Data can then be analyzed to identify trends and early indicators of problems, or opportunities for efficiency improvements.
- Take advantage of remote monitoring – Remote monitoring is valuable for industries that contain critical, automated systems. While remote monitoring of an individual system component is common, taking a big picture approach by monitoring the entire system performance, including incorporating predictive analytics, early detection, incident correction, and recommendations for maximizing performance, is the ideal scenario. These advanced programs provide operators peace of mind that system experts are monitoring their entire chilled water system, helping identify and resolve system issues before they turn into costly problems.
- Leverage an industry expert – Often, maintenance is performed at a component level with the intent to maximize performance of that single component – sometimes to the detriment of the overall system performance. Engaging a service and support provider that specializes in chilled water systems will ensure performance of the full system is optimized.
The Bottom Line
These are just some examples of maintenance activities that can be used to ensure proper chilled water system operation. By engaging with an expert service and support vendor, less time and money will be spent on reactive maintenance, thus ensuring that your system operates optimally during peak run season.
Stellar Energy offers comprehensive service solutions designed to maximize the life of Turbine Inlet Air Chilling (TIAC) systems, Central Utility Plants, and District Cooling systems. We provide flexible programs that help you maintain and optimize your facilities, including seasonal options, annual plans, long-term service agreements (LTSA’s), and Intelligent Monitoring (Stellar Energy’s cloud-based remote monitoring service). Components may include scheduled monthly maintenance, annual facility maintenance visit, seasonal startup, and shutdown activities.
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