Maximizing Your Environment with Optimum Chiller Performance

Tip #11

By Fawn Staerkel, Director, Healthcare and Performance InfrastructureTM, Johnson Controls Building Solutions North America

When operating at maximum efficiency, chillers can create a healthier health care environment, cut energy costs, and be tailored to fit almost any need. Ensure that your chillers are working for you instead of against you by considering the following three tips.

1. Troubleshoot to identify energy waste
To mitigate potential energy-wasting issues with your chillers, regularly review their operating data and ensure they are properly maintained. Look out for undercharged machines or slight changes in approach temperature, which can be indicators of dirty or obstructed condenser or evaporator tubes. In addition, low pressure machines that operate in a vacuum are susceptible to leaks, which reduce efficiency by displacing refrigerant vapor and increasing condenser pressure and temperature.

Keep up with scheduled maintenance, and also observe how the chillers are operating – for example, are they running with the lowest possible cooling tower temperature or are they being sequenced efficiently?

2. Improve and update preventive maintenance for chillers
Traditionally, chiller operators “log” the chiller daily so they have a record of operating data and can monitor changes over time. A study of operators shows that 50 percent log their chillers on at least a daily basis. Most operators use a paper and pencil method and keep the logs in a binder near the chiller. However, the ability to access and analyze this operating data is key to being able to troubleshoot energy-wasting chiller issues; therefore having the data in a paper log in a binder next to the chiller is not the most efficient or effective practice.

With the advent of the Internet of Things (IoT), data from chillers can now be collected automatically and stored in a cloud-based analytics platform. Connecting the chiller to the cloud allows you to:

1. • Send an alert to a monitoring center if a critical issue arises. The center can quickly notify the right people to take care of the problem.
   • Access the data remotely so a technician can begin troubleshooting the problem instantaneously, even if he or she is not on-site. The tech can arrive on-site prepared with the correct tools and parts.
   • Analyze the data using advanced fault detection and diagnostics algorithms, which can help identify deteriorating conditions like refrigerant leaks or fouled tubes before they cause a critical emergency.
   • Collect operating information like the average load over a 7-day period and condenser water temperature to analyze whether low-cost control strategy changes could be employed around sequencing or reducing entering condenser water temperature.

Non-destructive testing including vibration, oil and refrigerant analysis, infrared scanning, and eddy current testing are also ways to improve maintenance. The key is to perform integrated testing so that all the test results go back to a single center of excellence that analyzes each test and provides a combined report and recommendations based on the overall picture of the machine health provided by all the employed technologies.

3. Employ new-generation chillers
New generation chillers often eliminate some common maintenance issues, which helps to reduce the overall cost of ownership. For example, our YORK® YZ magnetic bearing chiller is oil-free, which eliminates oil changes and oil analysis. In addition, smarter panels feed more quality information into IoT systems, which improves predictive capabilities.

The latest generation of chillers provides efficiencies below 0.1 kW/ton and has proven performance maps that cover almost every HVAC application and operating condition. Technology developments continue to improve and optimize chiller components, but maintenance requirements remain a key factor in efficient and reliable performance throughout the life of the equipment. Tubes must be cleaned to reduce the negative effect of fouling on chiller performance, and water quality must be monitored and maintained to guarantee the integrity of chiller and variable speed drive heat exchangers.