Compressors Strive for Greater Efficiency
March 28, 2011
As a host of pressures - from demanding consumers to stringent regulations to rising energy costs - continue to bear down on the industry, compressor manufacturers are reiterating that energy efficiency is the best response to these issues.
As both manufacturers and end-users begin to demand greater efficiency as a way to control costs, compressor manufacturers say that their designs will all be geared toward achieving this. To put it bluntly, David Sylves, vice president, sales and marketing, Bitzer U.S. Inc., said, “Energy efficiency is driving Bitzer’s new compressor designs.” This emphasis on efficiency has already initiated changes in compressor design and technology development, and will continue to do so in the future.
CUSTOMERS DEMAND MORE FOR LESSDave Monk, director of engineering, Bristol Compressors International (BCI), put the desire for efficiency in simple terms: “U.S. domestic customers continue to demand more for less.” But there’s a multilayered meaning behind this simple statement. “ ‘More’ includes higher efficiency, lower sound levels, lower customer line rejects, and lower field failure rates, as well as higher levels of customer support, including shorter lead times for product delivery. ‘Less’ is obviously the cost of the product, but also demands advanced product support and lower inventory levels.”
Monk also noted that these customer demands are heard in the commercial sector as well. “Much like the customer requirements for residential products, commercial customers are requiring more for less. More than ever, customers are requesting higher efficiency refrigeration compressors for medium- and low-temperature applications. End-user customers are requiring higher efficiency equipment, from ice machines to cryogenic cooling freezers.”
As a result of this customer pressure, BCI has had to focus on not only the efficiency of its products, but also on the efficiency of its operations. Monk noted that BCI “100 percent builds compressors in the U.S.A., which allows on-time domestic customer delivery and less chance of product shortages due to potential ocean container issues.” He added that the company has a “zealous commitment to ‘lean’ manufacturing techniques,” which has also aided its goal of on-time delivery to customers.
Bill Brandt, director, compressor engineering, Ingersoll Rand Residential Solutions, agreed that compressor requirements are changing in part due to “more discriminating end-product customers.” He added, “To remain competitive, speed to market is essential.” So customers want their compressors fast - but they also demand quality. Brandt noted, “We use sophisticated analytical and statistical techniques in all areas of compressor development. Performance, noise and vibration, manufacturing processes, quality, and reliability are optimized through these methods, and testing is confirmation of analytical results.”
Frank Landwehr, vice president, marketing and product planning, for the Air Conditioning Division of Emerson Climate Technologies, agreed that customer demands for product reliability are a major influence on compressors. “Some of the most challenging issues facing our industry today involve consumer and end-user expectations for system reliability, durability, and length of service. Everything the consumer buys today is expected to start up and run the first time and also continue operating for a really long time, without needing costly repairs or replacement.”
One way that Emerson has chosen to address these concerns about reliability is by working closely with its OEM partners “to ensure that each compressor selected for a particular application is up to the task,” Landwehr said. In addition, for the commercial market, Emerson recently introduced CoreSense™ technology, which “uses the compressor as a sensor to diagnose, protect, and communicate system problems that could threaten the reliability of the system or its useful life,” Landwehr explained.
Manohar Reddy, global marketing product manager for air conditioning compressors, Danfoss, said that his company’s “main areas of focus are quality and efficiency - both in engineering and manufacturing compressors.”
He continued to describe the company’s approach to satisfying customers: “At the same time we’re also dedicated to developing high-performance products that contribute to a lower total cost of ownership and greater comfort, including temperature, humidity control, and noise reduction.”
According to Chris Bird, compressor product manager, North America, Tecumseh, “Original equipment and wholesale distribution customers we work with on a regular basis tell us they are looking for energy improvement without sacrificing for excess weight, noise, or cost.” While this may sound like a tall order, Bird said, “Tecumseh is in the process of redesigning fully 40 percent of our major compressor product offerings to meet the challenge.” He specifically noted that this effort recently resulted in “the introduction of our all-new AE2 compressor optimized for hydrocarbon refrigerant use.”
ADVANCING REGULATIONSAs the federal government has begun to enact more stringent codes and laws that regulate the HVAC industry, this has become an increasingly important factor in the manufacture of compressors. According to the manufacturers, these regulations have been the driving force behind some of their innovations, and they predict this will continue in the future.
For instance, Landwehr explained, “By far, the most significant advancements in residential air conditioning compressors have been in the area of energy efficiency. Increasing the minimum SEER levels from 10 to 13 SEER in 2006, combined with the 2010 regulated move to R-410A refrigerant for new equipment, has created significant interest in higher efficiency compressors to be used in all sizes and price points within the OEM’s product offerings.” As an example, he said, “To meet the challenge of regulatory changes over the past few years, new Copeland Scroll® compressors were designed for both fixed- and modulated-capacity operation. Within the modulated compressor space, some of the more revolutionary advancements have been made in the area of two-step modulation, like the Copeland Scroll UltraTech™ compressor designed for higher SEER systems, and the recently released Copeland Scroll® variable-speed compressor.”
Regulatory changes that are currently pending in Congress include the move to regionalized standards. According to Brandt, “The regionalization of efficiency requirements may drive region-specific products, and advanced thermodynamic cycles may become economically feasible, driving a new set of compressor requirements. As complexity increases, the integration of compressor and system characteristics will provide more efficient, lower cost products.”
Sylves added, “The political landscape in the U.S. is constantly changing, and we must closely monitor new regulations that impact our industry. New refrigerants, GWP [global warming potential], TEWI [total equivalent warming impact], carbon footprints, and sustainability are all hot topics that may impact future compressor designs.”
According to Monk, customers are focused on not only zero ozone deletion potential (ODP) refrigerants, but also zero-GWP refrigerants such as CO2. “Advancements in zero-GWP refrigerants are being applied in military applications, as well as some global locations, and are expected to be required within the U.S. market in the not-so-distant future,” he said. He added, “BCI’s reciprocating platform employing high-compression ratio-capable valving will provide an exceptional solution for the demanding requirements of these new refrigerants.”
Bird pointed out that Tecumseh’s redesigned AE2 is “designed for hydrocarbon refrigerant use, while offering up to a 25 percent energy efficiency gain over its predecessor.”
Reddy said that Danfoss has prepared for other industry trends, shifting to environmentally friendly practices. “For instance, Danfoss compressors are optimized for R-410A and R-407C refrigerants, and we have implemented using lead-free polymer bearings in some models, and we are fast moving to complete the implementation of use of these bearings in the remaining models as well,” he said.
Sylves also mentioned that CO2 compressors are beginning to find their way into U.S. supermarkets. “While CO2 systems are not yet as popular in the U.S. as they are in Europe, this green refrigerant option is growing,” he said.
DRIVING INNOVATIONBut it’s not just governments and regulators that are driving innovation and efficiency - it’s also concerns about cost. According to Landwehr, “Increasing concerns about energy costs, as shown by consumers, end users, and the government, are among the most important trends affecting compressor designs today.”
Monk also noted, “Higher energy costs are driving domestic equipment manufacturers to develop higher EER and SEER equipment. Higher efficiency can be attained by adding heat exchanger surface area (coil); however, that approach has its limitations and does little to address the fluctuating thermal load demands of the conditioned space. Recently equipment manufacturers have looked to compressor manufacturers to provide variable-speed products that can match those thermal load demands.”
Brandt added, “As energy costs increase, the cost of providing ultra-high efficiency in fixed speed becomes prohibitive or technologically impossible.” He predicted, “Capacity-modulated compressors will become the norm. New heat exchanger technology, which reduces system charges, combined with low-cost micro-computing controls, provides the opportunity for system manufacturers to totally control system operation, which allows compressor manufacturers to reoptimize their designs for narrower operating ranges and lower stress excursions.” Plus, he added, “All three factors will contribute to size and weight reductions.”
And according to Bird, advancements in variable-speed technology “will continue to drive the move toward greater control and flexibility in compressor utilization.” He continued, “Introducing variable-speed capability in residential applications is accelerating energy-efficiency improvements. Tecumseh is currently working closely with the world’s top R&F original equipment manufacturers in order to remain on the leading edge of that movement.”
Reddy also noted that the development of smart grid technologies will have an effect on the popularity of variable-speed compressors. “The development and implementation of smart home and smart grid technologies will further encourage the use of variable-speed compressors, as the benefits of variable speed will only multiply when incorporated into systems designed to control and reduce energy use,” he said.
Publication date: 03/28/2011