Efficiency, Regulations Drive Compressor Advancements
Latest Developments Center on Variable-speed Operation, Natural Refrigerants
CHICAGO — A major push behind energy efficiency has led many manufacturers to create speed-controlled compressors driven by next-generation refrigerants. And, not only are these units growing in popularity, they are being designed in a number of sizes and configurations with the intention of meeting consumer demands, regardless of the stature or application. Many of these next-generation compressors were showcased at the 2015 AHR Expo in Chicago.
“The market seems to be moving to cost-effective, fixed-speed compressor solutions that focus on capacity modulation and the optimization of IEER and IPLV performance,” said Eric Walthall, marketing manager, Danfoss. “But, there also is a rapidly growing demand emerging for variable-speed solutions that precisely match capacity to building load to give the end user superior energy efficiency.”
Danfoss’s inverter scroll compressors are engineered to provide superior part-load efficiency, intelligent control, and demand-response capabilities.
“Featuring a compressor design optimized for variable-speed operation with a permanent magnet motor, the Danfoss inverter scroll compressor VZH range precisely matches the capacity of the system to building load,” said Walthall. “The VZH compressor drive allows utilities to access the system in case of a demand-response event while also enabling the OEM or building operator to capture performance and reliability data, which increases energy savings and facilitates the expedited diagnosis and prevention of failures.”
The movement to variable-speed compressors as a way to meet the ever-increasing efficiency standards, or for expanded application range, will have the largest impact in the market in the next five years, said Joe Orosz, executive vice president and COO, Torad Engineering LLC.
“The need to increase unit performance is driving unit manufacturers to apply variable frequency drives (VFDs) not only to compressors but air-handling equipment, as well,” he said. “This allows the system to adapt to the ambient conditions in a way that gives greater efficiency over a much wider operating range.”
Torad’s rotary spool technology is designed to run over a wide speed range with relatively constant efficiency. “The machine can adapt internally, so it intrinsically has the ability to match the system operating conditions, whatever they might be,” said Orosz. “This is particularly beneficial at high turndown conditions where the spool can operate very efficiently.”
Karl Zellmer, vice president of air conditioning sales, Emerson Climate Technologies Inc., said the overriding trend he’s seeing revolves around modulation.
“Modulation comes in several categories, including variable-speed products, two-speed products, and digital modulation — ranging from 10 percent to 100 percent. In the commercial market, we’re seeing a growth in the demand of multiples, where you can have tandems or trios of compressors linked together.”
Emerson’s broad range of compressors are designed to fit each customer’s unique needs, regardless how big or small.
Zellmer said the company offers variable-speed compressors and drives for residential unitary 5-ton-and-below equipment and is launching variable-speed commercial 7.5- to 10-ton drives, granting the company coverage across all 2- to 10-ton markets. Additionally, the company’s UltraTech is being expanded in displacements and voltages to 2-6 ton, granting a broader range of use.
“Our variable-speed integrated solution offers significant energy savings and the highest levels of comfort and reliability for end users while streamlining system development time for manufacturers,” said Bart Powelson, director of commercial marketing, air conditioning business, Emerson Climate Technologies. “With this offering of Emerson brands, the industry can leverage the latest variable-speed compressor technology along with efficiency, precise control, and the protection offered by our integrated solution.”
David Sylves, director of inside sales and marketing, Bitzer U.S. Inc., said the company is focused on delivering quiet, highly efficient compressors. “Bitzer satisfies these elements with its ORBIT GSD Scroll Compressor series for a/c and heat pump applications,” he said. “Using Bitzer’s Advanced Header Technology (BAHT), OEMs can now combine uneven compressor sizes in tandem and trio applications to maximize IPLV performance. The patent pending BAHT header simplifies oil management without the added complexity that prevented the utilization of uneven models in the past. Numerous combinations of models within a frame size, or between our GSD6 and GSD8 frames, are now possible with common pipes, and a variable-speed drive can be added to one of the compressors, if desired.”
Embraco representatives said their compressors utilize natural refrigerants that are fully compliant with U.S. regulations.
The company introduced its Plug n’ Cool “EPC” sealed-unit line, a cooling solution for commercial refrigeration compressor replacements or retrofits, at the show. EPC units use R-290 refrigerant and are designed for grocery store and supermarket use. The units come completely sealed and are shipped fully charged with R-290, around which OEM design engineers can build market-ready, water-cooled display systems. The fully charged units eliminate the need for manufacturers to install R-290 charging equipment.”
John Prall, applications engineer, Embraco, said the company’s use of natural refrigerants benefits the efficiency of its products.
“Lower pressures and smaller charges lead to longer compressor life,” he said. “Propane has a higher volumetric efficiency than R-134a, so it is going to naturally provide more capacity in a smaller displacement.”
Embraco also introduced two high-efficiency variable-speed re-ciprocating compressors for 15- to 37-cubic-foot coolers. The VEGT8U R-290 compressor is Embraco’s high-efficiency Fullmotion variable-speed technology for 15- to 37-cubic-foot coolers. The EM2X3125U is an R-290 fixed-speed compressor built for use in 15- to 26-cubic-foot coolers.Embraco also launched nine additional products at the AHR Expo and presented a complete lineup of other R-290 compressors.
“Embraco compressors with R-290 offer great energy efficiency, low operating costs, easy maintenance, low noise levels, and a minimal impact on the environment,” explained Doug Schmidt, manager, commercial cooling solutions, Embraco North America. “R-290 is a sustainable refrigerant for commercial refrigeration because it combines economic need with environmental benefits.”
Tecumseh Products Co.’s manager of global marketing communications and branding, Michael Smith, said a growing demand for highly efficient products is resulting in the creation of more and more variable-speed compressors and electronic controllers. Additionally, these compressors are being created with environmentally friendly refrigerants, driven by government-initiated rules for the early phaseout of high-GWP (global warming potential) refrigerants such as R-134a and R-404A.
“Resulting products will benefit contractors because they will now be able to provide customers with more effective, environmentally friendly solutions,” said Smith. “Tecumseh’s new fractional HP compressors are optimized for use with ecofriendly hydrocarbon [HC] refrigerants. Tecumseh’s new AJ2 compressor is designed for use with environmentally friendly hydrofluoroolefin [HFO] refrigerants such as R-1234yf. Tecumseh has recently launched the VA Series variable-speed compressor for household refrigerator applications as well as the VR Series variable-speed rotary compressor for residential air conditioning applications.”
Carlyle Compressor Co. recently unveiled a two-stage CO2 transcritical compressor.
“Carrier got into naturaLINE™ CO2 container-unit refrigeration, and this compressor has a wide operating range of 20-115 hz,” said Michael Collins, application engineering manager, Carlyle.
“With CO2?, there are struggles to get it to be as efficient as a lot of the legacy refrigerants. But, engineering, evolution, and investments can solve a lot of those problems.”
A Mind of their Own
Intelligent HVAC products, which gather data and control system operation, have also become a focus of the market because of their ability to adapt a system to its environment and provide user feedback.
“These products are important because of the significant difference they can make in reducing electricity consumption and demand as well as diagnosing and preventing failures,” said Danfoss’s Walthall.
Carlyle Compressors Co. representatives teamed up with Automated Logic to develop a controller for their screw compressors.
“Screw compressors are a bit more complex with the safeties and controls, and, with this smart control, we’ve simplified how to control the slide valve and capacity,” said Collins. “By embedding motor protection, discharge temperature protection, and some of the control features, this makes it easier for the users as they don’t have to worry about these factors now.”
“Smart electronics are becoming more and more commonplace and, as a result, contractors benefit from the equipment’s simplified design and out-of-the-box programming,” said Tecumseh’s Smith.
The technology benefits contractors, as well, said Sylves.
“Technicians will benefit by sourcing high-efficiency OEM systems that maximize IPLV, such as a reduction in kilowatts per ton. In some cases, these systems may qualify for utility rebates for their customers.”
Bitzer also exhibited its 20-ton GSD60235 compressor, which provides quiet, efficient performance in a smaller frame.
“Many OEMs will be able to stretch the capacity of their smaller-frame units without a major redesign of the structure, making them more competitive,” Sylves said.
Walthall said the increased availability of data will enable installers to quickly and reliably diagnose and repair these intelligent systems, thereby increasing the value they can provide to their customers.
Emerson’s multiples (tandems and trios) are products designed to offer a cost-effective blend of comfort and IEER, which provides a balance for contractors to present at the kitchen table.
“We give the contractor a wide variety of technologies to select from to yield the best solution for comfort and energy efficiency. Some are more complex, while others are easier to apply. All of our units have a common theme of comfort and efficiency,” said Zellmer. “We’re offering choices, which allow customers to optimize solutions for specific applications.”
With an increasing variability across the compressor sector, Orosz warned contractors must be educated and prepared for all circumstances.
“Contractors, specifically in the residential and light commercial spaces, will have to improve their training and service skills to keep these new units operating at peak efficiency,” he said. “The owners will realize the benefit of lower energy costs, but there will be a greater requirement for highly skilled contractors to service these types of units.”
Publication date: 2/23/2015