Here is what we found:
• In small systems, look for rotaries, while scrolls dominate in the somewhat larger systems.
• Among the adds-ons, pay special attention to modulation.
• In terms of training, think electronics.
TYPESOne of those endorsing rotaries in smaller systems is Sam Piccarreta, director, Applied Technologies Group, Panasonic Industrial Co. “We definitely see the use of rotary compressors in residential a/c systems (both R-22 and R-410A), particularly in the 1- to 3-ton range,” he said. “The expected increase in rotaries will come at the expense of both recip and scroll-type compressors for residential a/c systems in this ton range.
“Given the advantages of the latest rotary technology - both with and without an inverter - such as small footprint, economy, high-efficiency models, high reliability, and ease of maintenance, it is likely to achieve a noticeable presence in the market.”
Gregory Johnson, strategic global marketing manager for Danfoss Air Conditioning, sized up the relationship of rotary to scroll. “There are two technologies: rotary compressors for mini-splits and multi-split systems, and scroll compressors that are dominant in light commercial and commercial systems. These are now the primary technologies used in U.S. ducted split systems.”
He noted, “Rotary compressors are popular in small systems because they are cost-driven, quiet, small and reliable. They are not the most efficient compressors on the market today. Their capacity is primarily up to 3 tons.”
He added, “Scroll compressors are very popular with R-410A refrigerants and in overseas applications. They are more efficient and reliable in the demanding unitary applications.
“Looking ahead in the residential market, the conversion to R-410A in 2010 favors scrolls. Scrolls have been gaining market share. We expect that trend to continue.”
Jim Rutz, director of marketing for Tecumseh Compressor Group, concurs.
“In North America, unitary air conditioning below 3-tons will be moving toward rotary while it is fairly obvious that the trends from 3 to 12 hp is scroll based.”
He did say that “in commercial refrigeration the picture is more complicated. Semi-hermetic technology continues to offer both efficiency and durability advantages over current scroll technology for low-temperature applications over 12,000 Btuh. Advances in variable-speed technology and electronic control may allow scrolls to close both the efficiency and reliability gaps.
Jim Mozer, vice president of marketing, Emerson Climate Technologies, Refrigeration Division, looked at scrolls in refrigeration from a somewhat different perspective. “There are many features that have made scroll compressors more and more desirable for commercial refrigeration applications. Scroll compressors are compact, energy efficient and reliable, so they are perfect for distributed refrigeration systems and walk-in coolers.”
TRENDSModulation is what seems to matter when it comes to the newest aspect of compressors. “Modulating scroll compressors are increasing in use in the commercial refrigeration industry due to their versatility, reliability and energy saving benefits,” said Emerson’s Mozer. “Digital scroll offers an innovative way to modulate the capacity of the compressor from 10 to 100 percent so that output precisely matches the changing cooling demand of the room.”
Danfoss’ Johnson agreed. “Right now, the biggest trend is toward modulating system capacities utilizing modulating or variable compressor technologies. The primary drivers behind this trend are rising energy costs and new legislation at the federal and state levels. Right now, 13 SEER is the federally mandated standard. Going above 15 SEER will require some type of modulating capacity in compressors.
“Long term, we see variable-speed compressors growing in popularity and taking the market by storm.”
Panasonic’s Piccarreta also votes for variable speed as a trend to watch. “With the advantage of increased comfort and efficiency, we expect variable speed, inverter-driven compressors will become more popular over the next one to three years for residential a/c systems. We also expect variable-speed compressors to become more common in the higher-end SEER systems.
Tecumseh’s Rutz saw a variety of trends on the horizon. “All manner of digital and electronic technologies are being introduced and developed to modulate capacity, control systems, and diagnose problems. AC versus DC inverters, signal processing, wireless communications, and integrated functions will become more common.”
TRAININGAll people interviewed for this article agree that contractors and technicians need to keep up with changes through training offered by manufacturers, supply houses, trade associations, vo-tech schools, and most any other source available.
“No matter what manufacturers do to simplify technology, it will be more complicated,” said Rutz. “The job will still require all the mechanical skills as before. But now we layer the ability to think about more abstract concepts. Electronic concepts will require greater emphasis in schools and in continuing education.”
Noted Johnson, “Technicians will require a more comprehensive knowledge of electronics. Instead of a standard thermostatic expansion valve, technicians will need to understand components such as electronic expansion valves, electronic controllers, sensors and inverter drives.”
Mozer said contractors and technicians should turn to manufacturers for “up-to-date training and hands-on attention. This hands-on, one-on-one education, along with online training, will be the key to keeping contractors and technicians up to speed on the latest industry advancements.”
Piccarreta noted contractor owners need to be willing to locate such information and pass it along to technicians. “With the increase in digital communication in both the components and controls of those components, service companies need to educate their personnel in electronics. Technicians will need to become more adept at monitoring controls and running electronic checks of control boards.”