Predicting the Future of RTUs
Manufacturers discuss where the market is heading in the next few years
With the U.S. Department of Energy (DOE) and industry stakeholders currently working together on a negotiated rulemaking setting new energy conservation standards for commercial package equipment, and with codes and standards mandating increased ventilation and higher efficiencies for this equipment, manufacturers are finding innovative ways to meet and exceed expectations while creating comfortable, healthy indoor environments for building occupants.
EVOLUTION OF THE AIR HANDLER
Some of the changes and improvements in air-handling units (AHUs) and rooftop units (RTUs) over the past few years include more IAQ options, more intelligent controls, increased energy efficiency, improved energy recovery options, and increased connectivity. “Features designed to increase system efficiency and enhance IAQ have gained significant popularity over the past five to 10 years,” said Stanley R. Wilkins, marketing engineer, Aaon Inc.
“Aaon has expanded its standard offering of energy recovery technology. This allows our rooftop equipment to be more effective in more climate zones across our market base. The Aaon energy recovery technology greatly increases the efficiency of our rooftop and air-handling equipment while maintaining space ventilation requirements. Aaon has also developed geothermal and water-source heat pump technology in our rooftop equipment.”
Eric Newberg, director, commercial product management, unitary products group, Johnson Controls Inc., said York’s Simplicity SE control represents “a new era” in how controls interface with commercial equipment.
“It starts with better connectivity tools, like our new Mobile Access Portal Gateway device that allows system access to the equipment through any smart device. Contractors can more easily complete the equipment installation and commission processes.”
The IntelliSpeed fan system and MagnaDry hot gas reheat system are also helping to control humidity and comfort better than ever before, Newberg said. “Humidity control has become an important part of IAQ and control. Our system is tested and AHRI [Air-Conditioning, Heating, and Refrigeration Institute]-certified for improved dehumidification.”
End users are interested in high-efficiency equipment, such as Lennox Intl. Inc.’s Energence® and Energence families, for a number of reasons, said Mike Ray, director, commercial rooftops, Lennox Intl. Inc. “Energy savings provided by these highly efficient products can reduce the operating costs for the building owner or operator.”
Farooq Mohammad, director, product management, Rheem Mfg. Co., said Rheem’s award-winning H2AC™ Rooftop unit featuring eSync™ integration technology is gaining traction.
“This system brings levels of savings and efficiency by capturing heat from the air conditioning process to preheat incoming water instead of letting it go to waste,” he said. “The H2AC Rooftop is an integrated air and water system designed specifically for full-service restaurants and other commercial applications in high demand of hot water.”
Ease of installation and service is influencing product design, as well.
“One thing Modine has taken to heart is the need to design systems that can be easily and quickly available to installing contractors,” said Ray Schaffart, marketing and sales support manager, Modine Mfg. Co. “Since these products have a lifespan measured in decades, it’s important the people who install and service them feel comfortable working on them.”
“[Lennox’s Energence] models reduce service and maintenance time with the isolated compressors, slide-out blower, and easily accessed gas compartment,” Ray said. “To assist the service technician, Energence comes standard with hinged panels with handles, eliminating the need to remove screws to gain access to these components.”
York’s direct replacement packaged rooftop units fit on a competitive units’ roof curb, removing the need for a roof curb adapter, Newberg said. “This product gives contractors more choices when it comes to replacing rooftop units.”
Chris Opie, director, commercial marketing, Carrier Corp., said ease of installation seems to be “at the top” of most RTU purchase decisions. He added that Carrier continues to see “strong consumer interest in efficient products with a reasonable return on investment as well as a renewed focus in advanced dehumidification solutions.”
Darren Sheehan, director of rooftop products, Goodman Mfg. Co., said customers have also placed great importance on serviceability. “We have incorporated customer feedback into both the design and features of the units to make them easy to install and service, both for product replacements and new installations.”
Finally, when it comes to data center AHUs, intelligent controls have made it possible to precisely control mission-critical environments better than ever before.
“Of all the capabilities on our Liebert air-handling units, the one that has gained the most popularity over the past few years is intelligent controls,” said Tifft Gannon, product manager, thermal management, Emerson Network Power.
“These types of controls, which are designed exactly for the sophisticated needs of the data center environment, offer data center managers higher energy efficiency, greater protection, and deeper actionable insight at the thermal management system and unit levels. At the unit level, intelligent controls constantly monitor and auto-tune key operating parameters, such as fan speed, compressor utilization, and economization. At the system level, intelligent controls enable machine-to-machine communication between units to prevent them from working at cross-purposes and allow the units to function as an aligned system, adapting to changes in facility-level demand as efficiently as possible to improve availability and reduce system wear and tear. This teamwork mode can be used in small and large data centers, creating a self-healing infrastructure that detects adverse
events and resolves issues before problems arise.”
One of the biggest drivers behind product innovation is the end user. Customers are more informed than ever before and, as a result, expect more out of the equipment they are purchasing.
“Broader awareness of the need for energy recovery modules [ERMs], controls, and IAQ continue and has increased over the last several years.” Schaffart said. “Overall, the heightened awareness of the technology and the benefits of improved energy efficiency and IAQ have had a positive effect for rooftop units. Building owners and managers are always looking for equipment with improved energy efficiency. That’s allowed Modine to expand its high-efficiency gas heating options from the unit heater line onto the company’s packaged rooftop Atherion ventilation systems.”
Carrier is continuously improving products based on customer feedback, Opie said. “New product development also relies heavily on our Voice of the Customer program and our Partners in Design council. This feedback has prompted enhanced serviceability and ease of installation.”
At York, the company utilizes customer input along with regulatory requirements to develop new commercial product designs. “For example,” Newberg said, “We heard from consumers that too much outside air leakage through the economizers was resulting in lost energy. We converted all of our rooftop unit economizers over to a low-leak design as a standard offering. … This also brings us in alignment with all appropriate ASHRAE ventilation requirements.”
Aaon spends a great deal of effort to understand what our consumers need, Wilkins said. “A great example is the patented Aaon D-PAC system. [It] was engineered to solve space temperature and humidity fluctuation in a pharmaceutical storage facility. Because the pharmaceuticals require specific conditions to remain viable, the typical fluctuations in temperature and humidity of standard rooftop equipment were not acceptable. The Aaon D-PAC system utilizes variable capacity technology, expanded economizer functionality, and a specific controls package to maintain space temperature to +/- 1°F and relative humidity to +/- 5 percent. … Aaon was able to work directly with consumers to understand their needs and engineer a solution.”
Since installation and serviceability have been major concerns for its end users, Lennox has worked to make these tasks as simple as possible. “Many of our customers have their own service departments and expressed significant interest in being able to quickly service these packaged units,” Ray said. “Feedback from these customers has assisted us in developing many of the serviceability features of our rooftop families.”
Rheem’s customers are always in the driver’s seat in the product development process, Mohammad said. “In fact, Rheem’s 360°+1 product design philosophy is based entirely on customer input and participation in conjunction with our product managers and engineers. On our current rooftop products, customer feedback led to the implementation of Rheem’s dehumidification technology and easy service-access features. We have also initiated a full rooftop platform redesign with our customers playing a central role in defining the scope of the redesign.”
In data centers, Gannon said facility managers are looking for proven, innovative technologies that will help provide substantial reductions in energy usage and greater design flexibility with higher levels of IT equipment protection. “Our Liebert air-handling units have a number of built-in features that our customers need. For instance, they utilize intelligent controls that provide advanced protection and automatically adjust airflow, temperature, and economizer function based on IT load and ambient conditions.”
Users are also looking for ease of use. “We have responded by completely redesigning our Liebert iCOM control platform to employ the touchscreen capabilities and intuitive interactions that are found in consumer products, such as smartphones and tablets,” Gannon said. “Our research also found customers who enjoy interacting with the systems are more likely to invest the time to use the full capabilities of the controls and be satisfied with the results.”
Some of the most influential drivers of product innovation are standards, regulations, and building codes. “The influence of governmental regulations can’t be ignored,” Schaffart said. Though, overall, “the impact is good,” he added.
“Regulatory action has resulted in significant increases in the amount of testing to support product changes,” Newberg said. “Efficiency increases, electrical changes, and changes to certification requirements are the primary drivers in the past few years.”
Regulatory action has a significant influence on the products Aaon designs and manufactures. “In recent years, ASHRAE has led the HVAC industry in setting guidelines for effective comfort cooling and heating,” Wilkins said. Aaon has worked closely with ASHRAE and AHRI to design and manufacture equipment that exceeds industry guidelines.
Wilkins added: “As of July 1, the DOE will take over jurisdiction of unit verification. Because of this regulatory action, it is now required to be listed with the DOE. This regulatory action will continue to have a significant impact on the products Aaon designs and manufactures.”
National and regional regulatory requirements are changing rapidly, Mohammad said, which is causing a tremendous amount of work behind the scenes to tweak and test designs, sometimes without a finalized deadline. “There are ongoing discussions at the DOE to raise the minimum-efficiency requirements for commercial products, and California’s Title 24 will also play a role in what types of products Rheem manufactures. It can be challenging to design products for future regulations, but Rheem continues to monitor the regulatory landscape to ensure we have a compliant line for our customers.”
The DOE’s and the Better Building Alliance’s Advanced Rooftop Challenge have also pushed manufacturers to achieve higher efficiencies than ever. “This resulted in the development of the Carrier WeatherExpert® LC Series Rooftop line, the most efficient rooftop product line we’ve ever released,” Opie said. “It exceeded the Advanced RTU Challenge specification by 15 percent. The private-public challenge provided a strong target for us to meet and exceed.”
One of the most important regulations affecting Liebert is ASHRAE 90.1, Gannon said. “The 2010 and 2013 versions of these standards, which provide minimum requirements for energy-efficient designs for buildings, are having a significant impact on the design of all mechanical equipment for data centers. Before ASHRAE 90.1-2010 was published, data centers were not required to meet any minimum efficiency. The 2010 version introduced minimum computer room air conditioner [CRAC] unit efficiencies. This version also stipulated incorporating economizers into the thermal management system design in new commercial buildings, depending on design, weather conditions, and system cooling capacity.”
Many of the aforementioned influencers will continue to impact AHU and RTU product design in the near future.
“The rooftop industry will be focusing on IEER efficiency ratings for future designs,” Newberg said. “This will result in more of a focus on unique forms of compressor staging or variable-speed compression. Systems will be designed to match building loads more closely than running fixed-speed systems. As the cost of technology becomes more affordable for variable-speed systems, it will become more widely used. The market for rooftop equipment is still primarily cost-driven.”
Wilkins also said the rooftop industry will continue to be driven by part-load energy efficiency. “Since a typical rooftop system will rarely see maximum design conditions, the majority of its run time will be at some point less than those maximum conditions. This means the system efficiency at those part-load conditions will carry more real-world value. We’re beginning to see more industry requirements for part-load efficiency ratings and anticipate that demand to grow. The part-load efficiency requirements will drive innovation since Aaon will continue to engineer ways to modulate unit capacity efficiently.”
Listening closely to what customers want will also help ensure products are meeting their various needs and influence product development in the future.
“As technology continues to progress and become more cost-effective, we will be adding features that will make our systems more efficient and easier to maintain. The next generation of customers is engaged with computerized and Web-based technologies. It would be logical that, in the years to come, there will be the expectation that commercial air conditioning systems add the capabilities for Web- or phone-enabled access.”
Regulations will also continue to push the industry into newer technologies and advanced solutions. “We may see inverter compressor technologies get more prevalent in rooftops, as well as advanced controls and more innovative refrigerant/heat-exchanger systems,” Mohammad said. “The challenge for the high-efficiency rooftop products will be to keep them cost-competitive and compact in size. To do that, we will have to develop innovative system solutions instead of relying on conventional and traditional ways of increasing efficiencies.”
Controls will also continue to evolve, Opie said. “As the industry comes up to the maximum technology barrier for full-load and part-load efficiency, the next frontier will be controls systems — both simple and advanced — that provide a sort of ‘continuous commissioning’ through fault detection, diagnostics, and prognostics to keep units in the best possible operating conditions.”
In the data center air-handler market, the industry “has only just begun to invest in energy efficiency in a dramatic way, and we believe this trend will continue to accelerate,” Gannon said. “Ultimately, increasing energy efficiency across data centers of all sizes, and implementing holistic site-level controls to integrate and automate action across all the systems in the data center, will push innovation for all products within the data center. With data centers consuming a significant amount of power on a global basis, it will be critical to link these systems together to maximize efficiency going forward.”
As for what the long-term future may hold for AHUs and RTUs, “there’s no ceiling,” Schaffart said. “That’s what makes the effort continuously challenging and worthwhile. Fortunately, it’s what we’re geared to do, so the quest continues.”
SIDEBAR: Unique Innovations — What Sets Our Products Apart
For this article, The NEWS asked participating manufacturers what makes their products stand apart. This is what they had to say.
“Aaon designs and manufactures HVAC solutions, not just commodity products. This sets Aaon apart because of the versatility of product application. A great example of that is the Aaon construction. Aaon utilizes double-wall rigid polyurethane foam-injected composite construction with 2,500-hour salt-spray-tested exterior corrosion protection on all Aaon rooftop equipment. The double-wall construction provides a minimum of R-13 insulation with no exposed insulation fibers and greatly increases cabinet rigidity while decreasing unit weight. There are many other unit features that exemplify our commitment to the HVAC market and allow Aaon equipment to be set apart from other similar products.”
Stanley R. Wilkins
“Carrier’s flexibility to offer advanced controls and also keep things simple with electro-mechanical controls provides us great strength. To be able to manage advanced dehumidification, advanced economizer control, demand controlled ventilation [DCV], and ASHRAE SZ-VAV, all on multiple tiers of product, with advanced control options, gives consumers a choice instead of requiring expensive and complex controls. The real differentiator is our people — from the technicians and engineers working in our state-of-the-art psychrometric laboratories to test and develop our next generation of products, our exceptional quality and manufacturing teams, and our front-line distribution teams. A Carrier expert is available locally for pre-sale questions, quoting, and to offer guidance during installation. That vast expertise and availability of parts are examples of how we strive to serve our customers.”
“Our indirect evaporative-free-cooling air-handling unit uses an epoxy-coated aluminum heat exchanger, which allows for much better dry effectiveness than polymeric heat exchangers. This means the unit can remain in dry operating mode for a much longer time before it uses evaporating cooling, resulting in reduced water consumption and lower water treatment costs. It also enables the flexibility of incorporating both water and electrical consumption costs into the sequence of operation in order to operate in the mode of operation that minimizes total cost of operation. The aluminum heat exchanger is designed to operate efficiently in both dry and wet operating modes, offering peak power consumption up to 50 percent lower than that of heat wheels that use dry heat exchangers. These dry heat exchanger systems often use more power at peak ambient conditions because they require a full refrigerant system for supplemental cooling, thereby increasing electrical infrastructure costs.”
Emerson Network Power
“All of our commercial units come standard with unit-based controls. We do this to protect the main system components like compressors and motors, but we also find it gives our products flexibility. We will not sacrifice quality in products, so we focus on equipment reliability, robust cabinet structure, and system performance as non-negotiable aspects of product design.”
Commercial product management
Johnson Controls Inc.
Unitary Products Group
“Contractors and end users recognize and benefit from the value of Lennox. While some efficiencies may be similar, there are still many standard features we provide that benefit contractors and end users. The Energence and Energence high-efficiency models incorporate the Prodigy 2.0 as a standard feature. This unit controller is easily adapted to building management systems through BACnet or LonWorks. Prodigy continues to feature a USB connection, which allows service technicians to download information about the operation of the unit — providing trends to assist them in understanding how to best set up the unit to match building operation.”
Lennox Intl. Inc.
“For rooftop units, manufacturers often rely on engineers to make or break them. Get specified and improve your chances of getting the job. But, engineers never actually buy or sell any tangible equipment. Instead, they are selling their expertise, proven reliability, and trust. They want a manufacturer who can be trusted, has quality products, and has specifiable features. More importantly, they want manufacturers that will be there throughout the entire sales process. Fortunately, Modine excels in these areas. We want to be the easy solution for engineers. From our nearly 100 years of HVAC experience to our Breeze Accuspec selection program to our state-of-the-art research and development facilities and our top-tier maintenance and start-up team, we can make an engineer’s life easy when it comes to selecting a rooftop unit.”
Marketing and sales support manager
Modine Mfg. Co.
“Rheem’s quality and reliability on the commercial rooftops, sturdy cabinet, and serviceability features are well regarded in the industry. Our H2AC technology puts us in a unique position in the rooftop category because it enables the air conditioning and water heating systems to work together. This brings new levels of savings and efficiency to businesses.”
Rheem Mfg. Co.
Publication date: 6/15/2015