Technology is advancing at a rapid pace and the HVAC & Refrigeration industry is no different. So, how has the chiller changed over the years?
Chillers vs direct refrigerant-based cooling system
Chilled water is used to cool and dehumidify air in mid- to large-size commercial, industrial, and institutional facilities. Chillers are primarily used to generate chilled water. Chillers are preferred to direct refrigerant-based cooling systems since they have low cost of ownership, offering cost savings to the owners of high-performance buildings over the lifetime of the systems. Well-designed chillers work with HVAC systems to deliver the right temperatures, humidity levels, and ventilation for the space, while also prioritizing low operating cost and energy efficiency as well as ensuring low sound levels and minimal environmental impact. Another advantage is that chillers contribute to the sustainability of high-performance buildings because they operate at lower head pressures, which uses much less energy and reduces greenhouse gas emissions.
The evolution of chillers through the years
Although the basic components of refrigeration systems and fluid chillers have remained unchanged for decades, improvements in compressor technology, refrigerant gases, manufacturing methods, and electronic controls have developed chillers into high-tech equipment with increasing functions and applications in not only comfort applications, but also in the industrial sector.
Electronics, Building Management Systems (BMS) communication, and data analytics have become powerful and are used to control chiller systems more efficiently than previously possible. These days, a single chiller control module can have multiple inputs/outputs and links via Modbus, BACnet, and other BMS communication protocols.
Basic chiller controls now include proportional integral derivative (PID) algorithms that read information during the operation of the chiller, monitor system parameters, and then control various functions, such as fans, compressor loading, and expansion valves, to achieve the required set point, and do so without overshoot or cycling on and off, thus saving energy.
Smart functions allow low noise operation during night-time periods, as well as floating set points, which can be controlled via ambient temperature probe readings. It even allows free-cooling during low ambient conditions and various methods of heat recovery with multiple set points for either domestic hot water generation or heating water for comfort applications.
One of the biggest areas of development in chillers has occurred in terms of controls. Chillers have become far more suited towards part load conditions. In reality, most applications for chillers demand them spending less than 1% of the time operating at full load. In fact, VSDs are on everyone’s list of notable new technology in terms of chillers. A multipurpose unit is actually sized to cover the maximum peak demand which, depending on the country where it is installed, may be in summer or in winter. However, in traditional comfort applications, the HVAC plant usually works at full load for a few hours every year; this implies that for most of the time, the unit works at partial load. The presence of variable speed drive technology allows units to effectively follow each combination of thermal loads required by the system, achieving total efficiency ratio (TER) values (calculated considering the unit’s performance in hot and cold water production) of up to 19% higher compared to traditional fixed-speed units.
The new age connected chiller
Another major change in controls is the ability to connect the chiller to the ‘cloud’. Information is sent from the chiller to the cloud where it is analyzed, which enables reporting to be generated on how the chiller is performing or if there are potential issues or problems. Data streamed from equipment to the cloud, advanced analytics, and remote monitoring are just a few of the technology trends that are changing how chillers are being serviced and maintained. With new insights into efficiency and access to the expertise of skilled technicians, today’s Smart Connected Chillers offer benefits including fewer disruptions, reduced downtime, and longer equipment life. Visualization can drive Improvements in Building Performance. Remember the old adage that a picture is worth a thousand words? That approach, used with data from connected chillers, takes complex information and presents it in a visual way, so critical knowledge is immediately conveyed. A dashboard provides an up-to-the minute look at how an equipment is performing. Today, the use of simple visual cues — like the use of red to highlight a problem — and increased customization of interfaces mean chiller data is no longer represented by numbers and spreadsheets, but offered through rich, interactive graphics
Chiller condition monitoring using cloud has many advantages.
First, it removes the necessity of manual log books which utilizes lots of time & effort. Secondly, with continuous digital data recorded on cloud, multiple personnel including site team, OEM & energy experts have access & suggest / take necessary actions. Finally, Machine learning can be incorporated into the analysis, which provides the user with suggested ‘fixes’ – so-called chiller insights. They can even alert the building owner to a problem before the tenant reports it and highlight imminent failures before the chiller actually fails. This makes maintenance and uptime easier and delivers more predictability.
Predictive Maintenance of chillers
How could chiller condition monitoring possibly evolve? Cloud technology ensures 100% data availability at any point of time with appropriate access level. Chiller condition monitoring involves integrating the chiller control with gateways & sending the live data to cloud. Rules & alerts can be set on the parameters which triggers SMS or emails or even displays on site to indicate users / OEMs that the normal operating condition of chillers is breached. OEMs having access to this data can immediately look at data trends remotely and identify suitable corrective actions. The OEMs can directly contact end-user for suggesting them immediate corrective actions that they can take at site or plan for direct inspection to resolve the problem. Status of critical components within the chiller can be tracked and deterioration can trigger actions like spare procurement by end-user before breakdown. This will eventually lead to predictive maintenance of chillers
Condition monitoring of chillers can help to track key performance indices on a continuous basis. The history data of these performance indices can help to identify whether the chiller is operating at its best efficiency. Usually, during a breakdown of chiller, the service personnel reads through the chiller logs maintained by the operator & tries to identify specifics patterns in data recorded to pin point what possibly could have gone wrong while the chiller was operating. Chiller predictive maintenance is a similar approach wherein the service personnel uses his knowledge to train the AI to identify specific patterns in data recorded. Chiller condition monitoring digitizes the age-old logs maintained by operators, thereby enabling the AI instance running on a remote cloud to work on this data. Identifying specific patterns with volumes of data available is tedious if done manually, which is getting solved with machine learning. With patterns identified, upward or downward trends can lead to identifying specific points where the equipment performance has started to degrade & suitable corrective actions can be triggered.
The future of chillers is smart
The future of chillers will see more developments into chiller predictive maintenance, where the OEMs will get notified on the events & proactively solve problems before the chiller breaks down. Further, more interactive displays at field would evolve, reducing manual effort to keep the chillers’ up round the clock and at best efficiency.