It is 2018, and this is not your father’s rooftop equipment. The old, reliable system taking up space on the roof has become so much more. Consumer demands for integration have inspired manufacturers to make a big push in smart controls for the commercial market. Smart rooftop units (RTUs) add a lot of value for both HVAC contractors and end users. While occupants appreciate the increased comfort control and efficiency, contractors benefit from the built-in diagnostics that contribute to preventative maintenance and the ease of installation and service.
SMART ROOFTOP UNITS
In the thriving IoT era, commercial HVAC products are now expected to provide value and equipment protection. This is done through technology that provides real-time data, such as scheduling, service and maintenance alerts, and energy usage reports. These features allow more system visibility and help prevent costly downtime later. Commercial customers are looking for intelligent features that facilitate communication with the industry-standard BACnet and BMS systems.
Rosa Leal, senior product manager — commercial products, Rheem Air Division, is excited about the advances in RTUs in general, and specifically the Rheem® Renaissance Commercial 7.5- to 12.5-ton line.
“It is a new platform of package air conditioners and gas electric units that are 30 percent more energy efficient than the current baseline technology available in most commercial HVAC units,” she said. “The line has been redesigned to match the industry’s commonly used footprint while complying with ASHRAE 90.1-2007, ASHRAE 90.1-2013, ASHRAE 62.1, and California Title 24 regulations. Robust design features, such as a solid single-piece top and durable panels, make installing and servicing the units quicker and easier.”
Leal was also quick to point out that some of Rheem’s technology includes factory-installed PlusOne® HumidiDry™ technology, ClearControl™ Direct Digital Control (DDC), and sensors that can connect to LonWorks™, BACnet®, and Modbus® BAS/EMS systems for remote monitoring and precise control.
Users of rooftop equipment are also demanding improvements in the overall building’s operational efficiency, so incorporating IoT solutions is a running trend in this area as well.
“By providing smarter controls, customers benefit from increased efficiency,” said Chris Opie, director of North American commercial marketing, Carrier Corp. “One major push in the light commercial segment is using variable air volume (VAV) systems. In response, Carrier has released the WeatherExpert® 48/50LC units to provide a full VAV system offering. The newly designed Carrier WeatherExpert VAV models, available from 23 tons down to 6 tons, use a dedicated i-Vu® controller that links communication between the system zone terminals and the unit to efficiently and comfortably adjust the air flow and compressor stages that are required.”
Manufacturers are connecting rooftop units by integrating mounted DDC controls. This allows the rooftop to have more intelligence than a unit controlled by a programmable thermostat. With DDC controls, rooftop fan and cooling functions minimize energy consumption and maximize performance.
“Daikin Applied also offers equipment with IoT capabilities,” said Steve VanPeursem, director, packaged systems, Daikin Applied Americas. “Our Intelligent Equipment® cloud-based controls solution connects rooftop units to provide users with operational data and energy analytics. This data allows owners and facility managers to maximize operational efficiencies for the equipment and building.”
Like almost every other segment of the HVAC industry, technology is moving at a fast pace. It causes people to speculate on what the next iteration of smart rooftops will look like.
“Efficiency gains for rooftops require increasingly advanced hardware and control technologies,” Opie said. “Rooftops will continue to get smarter and more integrated in how they are designed and operate. Likely, they’ll be more intuitive in nature while taking on more precise control and data collection of complex components and networks. Smarter prognostics and diagnostics may yield more accurate predictive maintenance and even more control of the unit from a remote location.
“Features previously only applicable to larger-size units are migrating to smaller units as technology and integrated operation improves,” he continued. “As these trends continue, factory integration of controls will continue to broaden, and smart controls on smart rooftops will be more prevalent.”
The big news in the rooftop market this year was that the new minimum efficiency regulations went into effect on Jan. 1. The Department of Energy (DOE) said this was the “largest energy-saving standard in history.” The rooftop air conditioner standards — which now cover new units found on low-rise buildings like hospitals, schools, and big-box stores — took effect in two phases, increasing minimum efficiency by about 10 percent as of Jan. 1, 2018, and by 25-30 percent as of Jan. 1, 2023. Standards for new warm-air furnaces that are typically installed in conjunction with commercial air conditioners also become effective in 2023.
“The HVAC industry is immensely affected by the new Department of Energy (DOE) regulations,” said Leal. “Keeping with our culture of innovation, Rheem has incorporated more high-tech components to help achieve new efficiency, better energy savings, and lower operating costs. The new Rheem Renaissance Prestige Series Commercial HVAC units utilize two-stage compressors, tandem systems, variable-speed direct drive motors, microchannel systems, and advanced controls. With all of these updates and more, our new platform is compliant with the upcoming enhanced 2023 regulations.”
Daikin Applied met the new 2018 efficiency standards on its rooftop equipment by using DDC controls to optimize the supply fan and mechanical cooling performance. The company has also improved on part-load efficiency in its current product portfolio by integrating advanced inverter compressors into rooftop equipment.
“The shift to regulate HVAC equipment’s energy performance based on part-load efficiency, or IEER, was the right move because it is driving reduced energy consumption overall,” said VanPeursem. “Daikin Applied Americas always prioritizes ways to reduce energy consumption, specifically on part-load energy performance because, on average, rooftop equipment is operating at part-load efficiency 98 percent of the time. For example, the mechanical cooling system at a retail store location of one of Daikin’s users normally operates at 40 percent of its full capacity, so it is critical for equipment to be able to perform more efficiently at part-load operation to keep energy costs and consumption down.”
Maintenance is not only important for the life of the unit but, more importantly, the comfort of the occupants in the building.
By utilizing a proper maintenance program, the customer is helping the unit make it to the full life expectancy. It is also essential to help identify any potential problems that could impede on the customer’s comfort or process.
“For example, a dirty condenser coil can result in an increase of 16 percent more energy consumption during compressor operation,” VanPeursem said. “Keeping up with routine maintenance increases the life expectancy of the unit and reduces the frequency of equipment replacement.”
One of the most important considerations for commercial HVAC systems is minimized downtime. Thanks to the innovative RTUs, contractors now have easier access to internal components to help speed service and installation.
“The new Rheem Renaissance units feature patent-pending designs, such as slide-out drain pans, adjustable filter racks, easy-access gauge ports, and slide-out blowers, to really simplify maintenance,” Leal said.
Additionally, enhanced controls enable notification of alerts and alarms for the maintenance team, which expedites diagnostics and repairs and reduces downtime. “Minimal downtime is critical for all active businesses,” Leal said.
Publication date: 6/18/2018