the market for chiller

THE MARKET FOR CHILLERS: Drives, Controls, Simplicity Chiller manufacturers are refining chiller packages for reliaability, energy efficiency, useability, low noise/vibration, and environmental friendliness

By MICHAEL G. IVANOVICH

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Arecent spate of chiller-line improvements by four maja jor manufacturers amounts to major tweaking rather than wholesale changes in chiller technology. The net result has been that efficiencies for large-tonnage water chillers have improved primarily from integrated- systems concepts rather than revolutionaa ary or even evolutionary heat-transfer technology. Intega grated variable-speed drives, factory-mounted controls usia ing openstandard protocols, and simplified chiller design and construction are what chiller manufacturers primarily seem to be striving for.

While chiller manufacturers have been hard at work on product development, the chiller market has shown resilia iency against a sputtering national economy. However, one sector of the chiller market— the replacement of chlorofa fluorocarbon (CFC) chillers—remains slow.

This article will present summary statistics on the large-tonnage-chiller market; discuss improvements made to largetonnage chillers from Carrier, McQuay, Trane, and York; and explore some of the technology trends evident from chillerline improvements.

THE CHILLER MARKET According to the AirConditioning and Refrigea eration Institute (ARI), the national economic downturn has slowed the replacement of comfortca cooling chillers that use CFC refrigerants. Manufa facturers predict that at the end of 2002, 48 percent of the original 80,000 CFC chillers will still be relying on refrigea erants the production of which was banned in the United States at the end of 1995 over concerns about the depletion of Earth’s protective ozone layer (Table 1).

An ARI survey of large-tonnage liquidchiller manufacturers revealed that 2,931 CFC chillers were replaced with non-CFC equipma ment or converted to non-CFC-refrigerant use during 2001. Some 3,124 more CFC chillea ers are expected to be replaced or retrofitted in 2002, leaving 38,281

CFC units still in use.

According to ARI, the rate of replacements and retrofa fits has been slower than expected. At the current pace, it will take the buildings industry until 2010 to phase out the CFC chillers still in use. Manufacturers reported to ARI that in 2002, they expect 360 conversions and 2,764 repa placements, bringing the total to 41,719 units, or 52 perca cent of the original 80,000 CFC chillers.

The slowdown in the global economy in 2001 was seen in the shipment of 7,171 non-CFC chillers for new buildia ings and CFC replacements here and abroad, a 7-percent decline compared with the 7,731 units shipped in 2000 (Figure 1). However, the rate of factory shipments is nearly double the pace of 15 years ago, when 3,744 units were shipped.

Manufacturers seem to agree that refrigerant selection should not drive chiller selection. According to Robert W. Schmitt, manager of industry relations for York Internata tional, energy efficiency currently is a bigger influence on equipment replacement than is refrigerant regulation.

However, Mike Thompson, marketing manager for Trane’s centrifugal- and absorption-chiller business, said the industry is used to the mechanical side of FIGURE 1. ARI annual-shipment data for largethis discussion, not the tonnage centrifugal and screw chillers for the period financial side. Therein of 1970 to 2000, including exports (open machines not lies the opportunity: included).

Owners simply have to ask for assistance.

“The most frequent comment that owners give for not moving forward on chiller changa geout is ‘no money,’” Thompson said. “The good news is that the effa ficiency of today’s chillea ers is such that the changa geout can be typically paid for by reductions in operating cost. A prime example is owners can lease the new chiller insa stalled. Typically, this lease rate will be less TABLE 1. Large-tonnage CFC chillers converted and than the operating-cost replaced by year. savings.

“Another example is, ‘I would like to buy a more-efficient machine, but it’s not in the budga get,’” Thompson conta tinued. “How would you like to buy the moreeffa ficient machine for the same price as the lessefficient chiller and then

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simply finance the difference over three years with zeropercent interest? The good news is that the monthly payma ments will be less than the savings.”

CHILLER REFINEMENTS The latest round of innovations in chiller technology marks steps toward simpler unit and package design, inca creased use of variable-speed drives (VSDs), and more-sopa phisticated controls that can be more easily integrated into building-automation systems.

Variable-speed drives. In 1979, York became the first chiller manufacturer to use VSDs as an option on a chiller. Since then, VSD technology has impa proved dramatically, and costs and size have come down significantly (photos A1 and A2).

Another benefit of VSDs is their impact on chiller-mota tor power factor. Carrier expects a power factor of 0.99 for its Evergreen VSS chiller; York also reports one in the neighborhood of 0.99.

Controls. All of the chiller manufacturers reported that their chiller controls are compatible with BACnet and LonTa Talk. Trane took a remarkable step by making its Integratea ed Comfort™ systems and Tracer™ building-management system standard with every S-Series chiller. Having these as standard features enables S-Series chillers to “sustain, monitor, and document their highest level of efficiency and lowest level of emissions throughout the lifetime of the chiller.”

Another feature of modern chiller controls are control centers installed directly on the chiller with graphical user interfaces (GUIs). These take a load off operators by makia ing it easier for them to access, analyze, and react to realtime data and trends. The highly visual GUIs help—and,

indeed, encourage—opera- tors to learn how to run their chillers more effectively and energy efficiently with less wear and tear. York’s OptiView Control Center is a good example of GUI-based chiller controls.

Simplicity. Chiller manufacturers are simplifying their products in different ways, resulting in fewer parts, smaller footprints, and greater reliability. For example, Trane’s oilfree bearings in the S-Series CenTraVac have resulted in a 40-percent reduction in the number of chiller parts by eliminating the oil system. York has reduced the size of the optional OptiSpeed drive package to the point where it no longer requires extra space. McQuay’s WPV chiller elimina nates the need for a separate pumpout vessel, which shrinks the footprint and enables the entire refrigerant charge to be stored in the compressor. Carrier’s new VSS chiller will have a totally integrated VSD as standard equipment, which reduces system complexity and cost.

MANUFACTURERS’ ANNOUNCEMENTS The following sections are summaries of announcema ments concerning largetonnage liquid chillers from Carra rier, McQuay, Trane, and York.

Carrier Corp.’s variable-speed screw chiller. During the second half of 2002, Carrier expects to begin taking orders for what it says is the world’s first variable-speed screw chiller, the Evergreen VSS (Photo B).

Using nonozone- Depleting HFC-134a refrigerant, the chiller system will be available in sizes below 500 tons.

According to Doug Bishop, Carrier’s director of largechiller global products, the Evergreen VSS will prova vide up to 48-percent better efficiency than comparabletonnage chillers that meet ANSI/ASHRAE/IESNA Standa

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dard 90.1-1999, Energy Standard for Buildings Except Low-Rise Residential Buildings, requirements.

Bishop said the Evergreen VSS marks “the first time that a variable-frequency motor-speed controller has been integrated into a chiller and controls design as a standard product. The result is the optimization of efficiency across the entire operating range, increased reliability, as well as reduced system complexity and cost.”

The Evergreen VSS also is promised to deliver fullload efficiencies below 0.52 KW per ton, which reduce peakdemand charges and size requirements for power-distributa tion equipment. Its integrated-partload- value (IPLV) effa ficiency is expected to be 0.30 KW per ton, which reduces energy usage and cost.

As a result of the line-conditioning benefits of the intega grated VSD, it should have a power factor of 0.99 or better (the industry average is 0.90), which reduces energy-transma mission losses by nearly 20 percent.

McQuay’s centrifugal-compressor water chiller. Availaa able in capacities from 220 to 430 tons, McQuay’s new WPV centrifugal-compressor water chiller (Photo C) comba bines the high efficiency of centrifugalcompressor performa mance with reduced vessel size to provide an economical alternative to rotary screw chillers. It is designed to operate as low as 0.58 KW per ton at ARI full-load efficiency.

MicroTech II™ controls with protocol selectability are designed for easy integration with most building-automata tion systems. A touch-screen user-interface panel gives operators state-of-the-art control for maximum operating efficiency.

The McQuay WPV centrifugalcompressor water chiller operates at significantly lower sound levels compared with rotary screw chillers and becomes quieter as the load is reduced. A standard oil pump delivers positive-pressure lubrication at startup, and hydraulic bearings provide long life without metal-to-metal contact. Liquidrefrigerant coolia ing allows lower operating temperatures for extended mota tor life.

“For smaller a p p l i c a t i o n s usually served by screw-compressor units, the new McQuay WPV chiller provides all the advantages of centrifugalcompressor perfa formance at a price that is competitive with typical watercooled screw-compressor chillers,” Al Torrence, marketing manager, McQuay chillers, said.

Controls with “protocol selectability” provide easy inta tegration into the building- automation system of the custa tomer’s choice.

The WPV features bolt-together construction with a small footprint. It can be easily disassembled and reassa sembled at the job site for retrofit installations. Compacta tion of the footprint, which is another benefit for retrofits, is accomplished through the elimination of the need for a separate pumpout vessel. The WPV’s pumpdown capabilia ity enables the entire refrigerant charge to be stored in the condenser.

The compressors are quiet at full load and become quiea eter as compressors unload. Also, they are capable of stable

chiller-capacity reduction to 10 percent for small load requirements.

Trane’s oil-free chiller. Trane’s SSeries EarthWise™ CenTraVac™ chiller (photos D1, D2), which will be available in 2003, eliminates the use of oil.

It features a simpler design that achieves high efficiency, reduced environmental emissions, and a lower total cost of ownership for optimal performance over the lifetime of the chiller.

Simplicity of design is one of several factors contribua uting to sustained efficiency, decreased utility-generated greenhouse-gas emissions, and reduced operating costs.

There is no oil to contaminate the refrigerant, a common and potentially significant cause of efficiency loss in tradita tional CFC-chiller designs.

Many larger chillers have 5 to 10 gal of oil. Trane recomma mends an annual oil analysis and changing the oil only when required. However, some manufacturers’ operating manuals suggest annual oil changes, which can result in a significant cost. By eliminating oil altogether, the S-Series design offa fers the ability to significantly reduce these kinds of maintena

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nance costs.

“Hybrid ceramic ball bearia ings and the use of lowpressure HCFC-123 refrigerant are absolutely critical to this oil-free design,” Jerry Arndt, vice president and general manager of Trane’s centrifugala land absorption-chiller business, said.

According to Thompson: “We also believe that there is a potential for up to an additional 0.5-percent improvement in efficiency because the bearings have significantly less friction loss. Testing is ongoing to document the specific impact, but especially when we are pushing the envelope to the degree we are with today’s chiller designs, this offers an excellent opportunity for additional efficiency improvema ments.”

The unit is hermetically sealed so that its initial refa frigerant charge is most likely its final charge. A chiller

running on a full refrigerant charge helps maintain peak efficiency, taking much less energy—and money—to operaa ate. The S-Series comes standard with a newly redesigned Earth- Wise Purge that uses a microprocessorcontrolled, regenerative cycle to automatically help keep the activated carbon in the purge at its ideal charge level. Monitoring and documenting purge run time, Arndt said, is the best indicator of refrigerant leaks, making it possible to detect and repair leaks before even a small amount of refrigerant is lost.

The simpler design of the S-Series chiller also should translate into reduced maintenance costs. Eliminating the oil translates into no oil checks, oil-filter changes, costly oil changes, or oil-sump heater.

As stated earlier, at the heart of the S-Series chiller is Trane’s ICS and Tracer™ building-management system, which are standard equipment. Through this combination of equipment and software, Trane’s customers can monitor key chiller information, including purge run time, condensea er and evaporator approach temperatures, real-time energy consumption, and evaporator and condenser temperature differential, to ensure optimal performance.

York’s centrifugal chiller. With chillers in the “real world” operating at off-design conda ditions nearly 99 percent of the time, York engineered its MaxE™ centrifugal chillers (Photo E) for maximum effa ficiency at both design and offdesign conditions. MaxE open-drive, centrifugal chillers are available in sizes from 150 to 2,100 TR using R-123 or R-134a refrigerant.

Equipped with the OptiSpeed™ variable- speed drive, the MaxE is said to offer unsurpassed integrated part-load value. It can reduce energy-usage ratios to new lows—0.40, 0.30, and 0.20 KW per TR—at off-design conditions.

The OptiSpeed features Adaptive Capacity Control logic, which continually optimizes chiller operation. It closely examines critical operating parameters and then determines the most-efficient way to operate. York reports that an OptiSpeed drive controlling a centrifugal chiller will reduce energy costs by 30 percent.

Bob Russell, vice president, global marketing, Engina neered Systems Group, said that over the last five years, the number of York centrifugal chillers sold with VSDs has increased from approximately 15 to 20 percent to more than 50 percent.

As standard equipment, MaxE chillers feature York’s OptiView™ Control Center, which uses sophisticated electa tronics and software to schedule and control chiller operata tions. Chilled-water temperature can be set to a resolution of ±0.1 F, eliminating the energy wasted by drifting from the setpoint by a degree or more. The OptiView Control Center has a highly developed graphical-user interface. It can be read quickly and easily and offers on-screen trend analysis of up to six different values selected from over 100 items. The OptiView Control Center can be integrated with a buildingautomation system using BACnet, LonTalk, or existing proprietary protocols

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