Things are changing in the chiller market — especially in regards to air-cooled models, variable frequency drives (VFDs), and refrigerants. Contractors are challenged to stay abreast of these trends in real-time. That’s the word from Bill Dietrich, product general manager, chillers, Daikin Applied.
Dietrich said the air-cooled chiller market continues to grow in the U.S., up 9 percent in 2016 on top of 11 percent in 2015. Additionally, since 2012, the overall market is up 27 percent. This growth is largely driven by the increased efficiency of air-cooled chillers and the rising cost of water and cooling tower maintenance.
“Air-cooled chillers used to be the lower first-cost and maintenance option at the expense of operating cost,” Dietrich said. “This is no longer the case, as new, higher-efficiency, air-cooled chillers will often outperform water cooling systems on an annual operating cost basis.”
As the cost and reliability of VFDs has improved, it is no longer a given that they are used on centrifugal machines only, said Dietrich.
Standard VFD-driven screw compressors are now often included in air- and water-cooled screw chillers, which offer better performance, eliminate the mechanical slide valve for capacity control and lower sound levels at part-load operation. Also, VFDs are being added to the condenser fans on air-cooled chillers to improve their part-load efficiency levels.
“Previously, VFDs on condenser fans were only used to allow for low ambient operation,” he said. “Air-cooled chillers with condenser fan VFDs result in part-load efficiency that closely matches more expensive water-cooled chillers.”
Finally, Dietrich noted that ozone-depleting hydrochlorofluorocarbon (HCFC) refrigerants, such as R-123, are coming up on their final phaseout dates and are no longer wise choices for customers.
“Customers should insist on safe, economical hydrofluorocarbon [HFC] or hydrofluoroolefin [HFO] refrigerants for new chiller applications,” Dietrich said. “Examples of wise, non-ozone-depleting refrigerant choices would be R-134a, -410A, or -1233zd.”
Even so, R-410A and R-134a are scheduled to be delisted in chiller applications under the U.S. Environmental Protection Agency’s (EPA’s) Significant New Alternatives Policy (SNAP) program starting Jan. 1, 2024.
THE IMPACT OF LOW-GWP FLAMMABILITY
Brian S. Smith, director of global marketing, chiller solutions, building technologies and solutions, Johnson Controls Inc., cited the challenges presented by refrigerant flammability as a major trend.
“Regardless of how quickly the HVAC industry could shift to low-GWP [global-warming potential] refrigerants, the available low-GWP options are limited with few-to-no nonflammable options for chillers and other commercial applications,” Smith said.
“This is not a problem for industrial facilities but is a real challenge for commercial building owners and contractors not accustomed to using mildly flammable refrigerants that cannot afford the added safety considerations or that are limited by building codes, which currently prohibit the use of flammable refrigerants,” he added.
Smith noted that low-pressure refrigerant alternatives to R-123 have nonflammable options available. Medium-pressure refrigerant alternatives to R-134a have both nonflammable and flammable options while high-pressure refrigerant alternatives to R-410A are all flammable.
“R-410A is the leading choice for rotary and scroll compressors used in residential and commercial systems,” he said. “These applications include systems with direct-expansion coils in the conditioned airstreams or coils that could be applied in poorly ventilated areas that could allow an unsafe concentration of the refrigerant to collect in the event of a leak.”
Safety standards, such as ANSI/ASHRAE Standard 15, “Safety Standard for Refrigeration Systems and Designation and Classification of Refrigerants,” are in various stages of revision to reflect safe ways to apply some of the new refrigerants. Smith said it is likely the industry will see special considerations — and possibly limitations — on the use of flammable refrigerants in some applications.
“Perhaps the greatest challenge lies not specifically in the design, manufacture, or application of the equipment but in the overall safety standard and building code revision and adoption,” he said. “Although the standards and codes may be revised, historically, the adoption of these standards into local building codes lags their creation. The current cycle of revision is underway, and in order to permit the use of some flammable refrigerants, building code adoption of the new texts would need to occur at an unprecedented pace.”
SEEKING LOW COST OF OWNERSHIP
Evolving regulations and increasingly stringent energy-efficiency requirements have created a need for building systems, technologies, and products that help businesses lower their building’s carbon footprint and deliver high-efficiency performance, said Vijay Deshmukh, centrifugal chiller portfolio leader, Trane, an Ingersoll Rand brand.
As a result, building owners are looking for partners with the right expertise and solutions to help them meet these goals.
One outcome of this trend, Deshmukh said, has been the increased demand for building designs that help lower annual energy use, reduce utility bills, and provide the lowest cost of ownership over the life of the building. By taking a systems approach, contractors can better position themselves to help building owners and managers achieve their sustainability goals and maximize building performance.
“While it’s important to choose equipment that delivers high-efficiency performance, it’s even more critical to take into consideration all the systems within a building,” Deshmukh said. “This is important because HVAC equipment and system components must operate together to achieve optimal results. Installing a high-efficiency chiller alone may not yield the building performance customers are seeking. However, if contractors place greater emphasis upon total-system efficiency instead of chiller-only or equipment-only optimization, they are better positioned to ensure all components of the system — not just the chiller — integrate for seamless operation and energy savings throughout the life of the system.”
Deshmukh noted there are tools and resources available to help contractors, and that by working with a knowledgeable manufacturing partner, contractors can access system analysis tools and system-level building solutions that will help them determine the best results for their customers.
“For example, design engineers at Trane focus not only on the individual chiller but also on how the chiller will perform in the specified building application,” he said. “Trane’s chiller manufacturing and testing facility is capable of evaluating chiller performance using the customer-defined parameters. Before it leaves the factory, the chiller’s performance is validated by simulating the conditions at which it should operate once installed. Following up with the proper service and maintenance plan will further ensure that the building’s systems and chiller operate at peak performance for the life of the equipment.”
Publication date: 5/22/2017