The European F-Gas regulation and the phasedown of high-GWP refrigerants — and resulting impact on refrigerant price — have driven recognition in all regions that high-GWP refrigerant use comes with long-term environmental and cost risks. That’s according to Drew Turner, global marketing manager - Oil-free Solutions, Danfoss. In the U.S., in the absence of federal direction, states and cities (including California and the growing U.S. Climate Alliance) are taking steps to reduce high-GWP refrigerants, driving change throughout the industry.
“Regulations that focus on environmental sustainability and energy efficiency are creating opportunities to improve overall HVAC products and system designs as the industry continues to evaluate long-term viable solutions,” said Brian Smith, director of global marketing - Chiller Solutions, Johnson Controls Inc. “The HVAC market is continually driving toward system efficiency, sustainable solutions, connectivity, and cloud-based services.”
Chiller technologies align with these market trends.
“Flammable refrigerants will require changes to not just equipment, but also to building design, handling, maintenance, and operating procedure,” Smith continued. “New, holistic approaches are needed that consider the life cycle of the equipment within its environment, regarding costs, greenhouse gas emissions, and interfacing with constantly evolving data management systems.”
By 2050, it is expected that 70 percent of the world’s population will live in cities, compared to 54 percent today, said Turner. In fact, about 77 million people are moving from rural to urban areas around the world each year.
“This is causing an accelerating trend toward equipment optimized for retrofit applications, with minimized footprint and sound levels,” Turner said. “The centralized fossil fuel-driven electric grid is shifting to one that is decentralized, with microgrids and the integration of renewables. With that is coming a shift to ‘electrification,’ changing equipment that formerly used fossil fuels, primarily for heating, to become electric-driven. The trend toward energy storage is being influenced by the periodic availability of renewables and the resulting disconnect with demand.”
A related buzz term is the water-energy nexus, which refers to the issues surrounding cities’ needs for water and the energy consumed to treat and transport it.
“This has driven recognition that these costs should be accounted for in making equipment decisions,” Turner said.
Chiller component efficiencies are approaching practical and, in some cases, thermodynamic limitations, said Smith. At the same time, the ways in which HVAC systems are operated offer opportunities for energy savings that are proving to be much greater than smaller incremental savings in certain component technologies. For example, the York® YHAU Chiller/Heat Pump is designed with absorption technology that utilizes zero-GWP water as a refrigerant, and uses available waste heat rather than disposing of it. It provides a dual benefit for end users on overall energy consumption and lower operating costs.
“System efficiency, while challenging, is becoming prevalent in building and equipment design through Green Globes, the USGBC [U.S. Green Building Council] LEED green building certification program, and other programs with the intent to help building owners measure and reduce energy consumption,” he said.
That includes advanced control schemes, model predictive control, system optimization, artificial intelligence, equipment learning (to optimize the real-time complexities of operating systems), and wireless connectivity for remote aggregation and analysis of system data (to inform operational decisions and identify and prioritize maintenance schedules to avoid unplanned or extended downtime for repairs).
“Whether it is global, national, or local-level regulatory decisions, sustainability and the efforts to reduce lifetime greenhouse gas emissions will continue to be a focal point, focused on improving efficiency and driving refrigerant choice,” Smith said.
Refrigerants are no longer a set-and-forget factor with equipment installation, said Turner.
“The market has recognized that chillers spend a significant amount of time operating at off-design or part-load conditions,” he said.
Expectations continue to grow around technology and equipment turndown capability, either through variable-speed operation or additional compressor technology unloading steps.
“This is partly driven by a growing understanding that the average chiller is oversized to even the design load,” Smith continued. “Not only are the average chillers spending more than 99 percent of their time operating at capacities below the design point, but the chiller is oversized to that design point.”
This has led to revisions and increases/improvements of chiller part-load performance metrics in the U.S. and other regions. It also spurred a growing trend toward testing on real-life operating conditions, including after manufacturing as well as during ongoing commissioning through monitoring and instrumentation and/or recommissioning.
“While air-cooled chillers were typically seen as a standard or ‘packaged’ product, customers now expect much more from them,” said Chris Opie, vice president, product marketing and platform strategy, Carrier Commercial HVAC Global Equipment. “To gain meaningful efficiency increases, the entire system should be evaluated. Instead of providing just chilled water at nominal conditions, they now need to have much broader operating ranges to increase the performance of the entire system. Heat recovery, free cooling, surge-resistant compression, and low-lift performance can enable better overall system efficiency. Based on their building’s specific needs, air-cooled chillers are approaching the level of customized, application-specific products. This means different levels of energy efficiency, wider operating range, and extra quiet, all while fitting into the footprint of the machine they are replacing.”
Chillers are getting better at connecting and reacting to demand-side grid services requirements, which relate to the grid decentralization trend, Turner said; it includes enabling demand response, load shifting, and demand limiting.
They’re also getting better at tracking and optimizing their real-time performance and managing it, or notifying operators to manage it, over time.
“This goes for component and equipment reliability as well, with chillers developing the capability to track and report issues before they happen, based on the factors which drive them.”
Predictive service would automate processes like chiller and plant optimization and issue diagnosis, which is valuable for not only end users but those responsible for the service, too.
“Both have been ongoing goals for chiller manufacturers for years but were not significantly possible until recently,” Turner said.
Carrier’s AquaEdge® 19DV water-cooled centrifugal chiller utilizes lift-optimization technology to allow a chiller with excellent cooling efficiency to also provide up to 120°F of energy-saving hot water. This can eliminate natural gas consumption, lower utility costs, and reduce carbon footprint.
“This chiller is also able to provide free cooling, which can easily meet many new building code requirements,” said Opie. “The chiller’s unique ability to both efficiently heat and cool can result in thousands of dollars in energy savings per year, as well as reduce equipment maintenance costs and mechanical room space.”
Its advanced two-stage compressor is designed for ultralow-GWP refrigerant R-1233zd(E), with a GWP of 1.34, lowering energy consumption and reducing CO2 emissions throughout its life cycle.
“Next-generation chillers will enable buildings to dramatically reduce energy consumption in colder months, by enabling free cooling and reducing energy consumption and water usage year-round by enabling heat recovery, all while providing world-class levels of cooling performance,” Opie predicted.
Carrier® SMART Service, a remote connectivity/analytics program, is now available in all new Carrier AquaEdge chillers with product integrated controls. The option provides a proactive strategy for equipment and system management that analyzes operating trends for informed decisions about comfort demands, implementing service, maintenance or repair events, and improving a building’s financial performance.
“Carrier SMART Service uses wireless cellular communications technologies to continuously stream operating data to the cloud in real time, directly from your chiller’s product integrated controller,” said Opie. “The data is then captured within our IoT platform for ongoing insight into your chiller’s health.”
Johnson Controls offers Smart Connected Chiller Services, targeted to bring building owners and facility managers best-in-class technology, energy savings, operations management, and performance using the Johnson Controls Smart Chiller Support Team and Dashboard. Remote monitoring and dashboards are available via computers and smart devices.
“This technology provides deep-dive analysis to better evaluate chiller performance and to proactively address maintenance or operational issues and ensure chiller uptime,” Smith said. “In addition, Smart Connected Chiller Services assist local Johnson Controls service teams in the United States with delivery of customer-facing reporting and technical articulation of data.”
Similarly, Johnson Controls Chiller Plant Optimization offers predictive algorithms that continually monitor operating conditions and make recommendations or real-time BAS commands to cut energy and water costs through changes to system sequencing and set points.
“Plant room-wide optimization software historically focused on maximizing efficiency by reacting to current conditions, whereas the latest generation of tools minimize cost, not just energy use, over a time horizon based on predictions of future conditions,” Smith said. “These technologies offer opportunities to optimize initial cost and operating costs. They also improve product and system reliability, resulting in increased equipment uptime through monitoring operations and operational trends.”
A LOOK INTO THE FUTURE
In the next five years, Johnson Controls expects continued focus on total system energy use and refrigerant choice, along with an increased awareness of lifetime greenhouse gas emissions through indicators like TEWI (total equivalent warming impact) or LCCP (Life Cycle Climate Performance).
“We’ll also be able to provide more capable analysis and accurate predictions because of increased access to equipment data and advanced diagnostics,” Smith said. “Magnetic bearing technology is improving chiller operational efficiency and decreasing maintenance requirements, which is leading most manufacturers to incorporate it in new chiller designs for optimal performance.”
He also predicted growing opportunities in chiller technologies including combined heating and cooling systems leveraging absorption chillers, heat pump chillers, heat recovery chillers, variable-speed drives, variable primary flow, and series-counterflow.
Turner expects to see an increased use of oil-free compressor technology in chillers.
“Oil-free compressor technology offers numerous advantages in terms of efficiency and sustainable performance,” he said. “Recent advances have expanded the oil-free compressor operating map, allowing users to deploy this technology in higher-lift chiller applications that have historically used positive displacement compressors.”
Danfoss’ Turbocor TTH/TGH compressors are an oil-free, variable-speed, magnetic bearing compressor solution optimized for high lift (differential temperature/pressure) applications like air-cooled chillers, heat pumps, heat recovery applications, thermal storage, and low-temp processes. They are available with low- and ultralow-GWP refrigerant options. As the industry prepares for a transition to low-GWP but flammable refrigerants, manufacturers need to be prepared with equipment modifications, said Turner. Danfoss is supporting the timely development and implementation of updated codes that enable their use.
“This is the No. 1 factor, as the owners, operators, and service organizations are looking to all of us to be ready for them,” he said.
Johnson Controls is taking a cautious approach to the use of flammable refrigerants.
“Safety is our first priority,” said Smith. “While the implementation of a limited amount of flammable refrigerants is likely inevitable, identifying the level of utilization is still open for debate. The National Fire Protection Agency is involved in these discussions, and there isn’t much clarity on exactly where things are headed.”
In the meantime, Johnson Controls is testing new fluid options from refrigerant producers to determine what design changes can be made and what technology advances will be required without negatively impacting efficiency or increasing CO2 emissions.
“Careful evaluation of the trade-offs between efficiency, safety, flammability, cost, and availability is required — not just by the equipment manufacturers and contractors, but also by building owners in terms of operation and maintenance,” he said. “This will require that new rules, new products, and likely new services are created to address several of these trends.”
Publication date: 7/1/2019