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On Jan. 1, 2023, the U.S. Department of Energy’s (DOE’s) second efficiency increase for rooftop units (RTUs) went into effect, which required a 15% increase in part-load (IEER) efficiency. This was in addition to the 13% increase in energy efficiency that was already required in 2018. Not surprisingly, manufacturers at the AHR Expo were eager to show off their latest energy-efficient RTUs, many of which can also be used to meet building owners’ decarbonization and electrification goals.


Setting a New Precedent

Just a few weeks before the AHR Expo, Trane released the Precedent heat pump packaged RTUs (12.5-25 tons) with a new hybrid, dual-fuel option. The line now includes 3- to 25-ton, light commercial, packaged rooftop heat pump units and the addition of a new 25-ton capacity. Precedent rooftops meet and exceed DOE 2023 efficiency requirements and feature a host of upgrades, including the new Symbio 700 controller that optimizes performance, improves serviceability, and provides unit connectivity.

Aaron Olita at Trane Booth.

HYBRID OPTION: Trane’s Aaron Olita discussed the Precedent heat pump packaged RTUs, which feature a new hybrid dual-fuel option. (Staff photo)

“In order for manufacturers to meet the new DOE efficiency increases that went into effect at the beginning of 2023, rooftops had to become more complex,” said Aaron Olita, director of unitary product management at Trane Commercial. “With a more sophisticated product, we included a new controls platform, Symbio 700, which is on our light commercial rooftop products. There is an app to connect directly to the controller to help set up the equipment and diagnose service needs that may happen in the future.”

Reducing carbon reliance is a growing priority for many building owners, said Olita, and the Precedent heat pump packaged RTUs are ideal for companies motivated to meet their decarbonization goals or local electrification mandates.

“Building owners in traditional gas-only geographies can now enjoy the benefits of dual-fuel heat pump technology,” he said.

Hybrid heat pumps overcome the geographic challenges that traditional heat pumps encounter in keeping building occupants comfortable in cold climates. In this type of system, the electric heat pump serves as the primary heating source, while natural gas is activated as needed. Precedent dual-fuel heat pumps provide a means to meet electrification initiatives while ensuring comfort even in the most extreme temperatures, said Olita.

“Changes to the environment, regulations, and incentives will have an increasing impact on business and building operations,” said Olita. “By strengthening Trane’s rooftop portfolio with greater intelligence, increased efficiency, and flexible control, contractors and engineers can advance their strategies and designs to support decarbonization and help customers reduce operating costs. Trane has one of the most expansive portfolio of electric heating products currently available, with more on the way to meet evolving decarbonization needs.”


Rebel with a Cause

The Daikin Applied booth focused on building solutions for a sustainable future. In particular, energy efficiency across all parts of their portfolio, as the company highlighted new and innovative solutions, including inverter heat pumps, connected intelligence, sustainable IAQ solutions, and next-generation refrigerants.

“We are seeing a major shift toward more environmentally friendly and efficient standards for HVAC systems,” said Chip Grech, applications engineer at Daikin Applied. “We believe that sustainable buildings start with efficient buildings and we look forward to unleashing systems that have a large impact without leaving a large footprint.”

Chip Grech at Daikin Booth.

AIR QUALITY: Chip Grech showed how Sorbent Ventilation Technology works on Daikin Applied’s Rebel rooftop.. (Staff photo)

Those systems include the Rebel Applied packaged rooftop system and Vision and Skyline air handlers, which were highlighted at the booth. Rebel Applied was recently upgraded with Sorbent Ventilation Technology (SVT) from enVerid, as were the Vision and Skyline air handlers. Vision and Skyline with SVT are the industry’s first total-air-quality systems that combines the benefits of sorbent media with a class-leading, semi-custom air handler, said Grech.

The integrated SVT system from Daikin improves IAQ by removing CO2, volatile organic compounds (VOCs) such as formaldehyde, and other contaminants using sorbent filtration that captures pollutants while allowing oxygen and water to pass through freely, resulting in cleaner air. This integration also benefits contractors, as it makes sizing, installation, and facility design easier for new and retrofit construction, said Grech.

“The integrated system allows engineers and building owners to right-size the ventilation for each zone in a single, integrated air handling unit — with one set of ducting and one mechanical space,” he said. “In addition, the use of SVT reduces outdoor air loads, resulting in smaller capacity, and less peak and lifecycle energy consumption, providing a more sustainable building solution that also supports electrification when paired with heat pump-driven technologies. SVT also reduces peak cooling and heating loads, resulting in reduced carbon emissions.”

The bottom line is that the upgraded Rebel Applied, Vision, and Skyline with enVerid SVT give contractors and HVAC professionals an efficient system for providing high-quality indoor air while reducing energy use and carbon emissions, said Grech.


Make the Right Choice

Johnson Controls’ newest innovation in rooftop units is the York Sun Choice ultra-high-efficiency RTU. These 12.5- to 23-ton RTUs launched in late 2022 and surpass DOE 2023 efficiency standards by up to 45%. The heat pump model of the Choice RTU meets decarbonization goals by eliminating the use of combustion gas and surpasses DOE 2023 standards by up to 6%.

“Choice RTUs achieve ultra-high efficiency through a combination of Copeland high-efficiency ZPKZ fixed-speed, ZPS two-stage, and ZPV variable-speed compressor technologies, along with ECM outdoor fan motors to deliver the highest part-load efficiency in their class,” said Jason Carter, senior product manager of ducted systems, North America, at Johnson Controls.

They also feature multiple airflow strategies, including VAV and exclusive IntelliSpeed discrete fan control (DFC) with variable-capacity control. In addition, Continuous Reset Single Zone (CRSZ) control helps improve temperature and humidity accuracy for better occupant comfort.

“Choice RTUs are designed to lower initial project costs, which can create a compelling value proposition for contractors working on retrofit application — especially when the current system is unreliable, inefficient, or unable to meet today’s IAQ standards,” said Carter. “Contractors will also find a simplified installation process and features designed for easy maintenance when specifying Choice rooftop units.”

Embedded Smart Equipment controls technology makes startup, installation, and commissioning processes faster and easier, said Carter, while the lightweight design and direct replacement footprint eliminates the need for additional structural engineering analysis used in replacement applications. Single-side access, available for all serviceable items, including connections, coils and compressors, streamline maintenance.

And while the most pressing change for many is the updated DOE 2023 efficiency requirements, Carter added that it is important for contractors to stay focused on the upcoming HFC phasedown.

“While the impending HFC phasedown may not feel as urgent as what is happening now in 2023, it’s important to prepare and stay informed on best practices, as they involve such issues as reclamation and recovery practices and cylinder tracking and disposal methods,” said Carter. “Contractors can also begin renewing EPA Section 608 licenses and creating a strategy to upgrade equipment that may not be compatible with A2L refrigerants. Remaining proactive in advance of this change can help to ease the transition and minimize disruptions.”


New Year’s Resolution

Rheem featured two new RTUs at the AHR Expo: the Rheem Resolute 30-ton packaged system and the Rheem Renaissance 15- to 25-ton unit, the latest addition to the Renaissance lineup, which now offers products from 3 to 25 tons. Both of these new rooftop units were designed to make installing and servicing easier for contractors, said Nancy Grimm, senior commercial marketing manager at Rheem.

“The Resolute 30 ton boasts a mix of options to enhance installability and serviceability, such as the PlusOne ServiceSmart package, which includes elements like a slide-out, internally sloped condensate drain pan, standard hinged access panels, and standard single-point wiring,” she said. “The Renaissance lineup features an improved footprint design that allows direct replacement of most other manufacturers’ products without the need for a new roof curb adapter, which impacts the overall cost and labor needed for the project.”

The wiring and piping connections on the Renaissance are also thoughtfully placed, said Kevin Nguyen, commercial sales engineer at Rheem. “Every wire is color-coded for a different function, and it's very neat. In addition, it’s easy to access the compressor and the other components because the panel doors are on hinges. We put a lot of work and effort into designing the Renaissance so that it’s easy to repair and replace.”

Kevin Nguyen at Rheem Booth.

EASY TO SERVICE: Kevin Nguyen showed how easy the Rheem Renaissance rooftop unit is to install and service. (Staff photo)

The Renaissance line’s flexible footprint with two return options virtually eliminates the need to change previously existing piping, wiring, or ductwork placement. In addition, airflow is convertible, meaning downflow or horizontal airflow can be selected, depending on the application’s need, said Grimm.

“Renaissance products include the patent-pending Velocifin gas heat exchanger and are also the first in the industry to feature indoor and outdoor interlaced microchannel coils,” said Grimm. “These innovative features enhance overall and part-load performance to deliver the performance today’s businesses expect.”

In addition to features that make maintenance easier and faster, the Resolute lineup includes factory-programmed VFDs with plug-and-play installability and Rheem PlusOne HumidiDry for full-load dehumidification with part-load cooling. The lineup is also BAS-compatible through ClearControl via BACnet, LonWorks, or Modbus, allowing owners to connect and control the system using their preferred option.

The DOE 2023 efficiency standards provided Rheem with the opportunity to innovate new technologies to create an even better product line for contractors and homeowners, said Grimm, and the company continues to lead the industry in decarbonization and overall sustainability efforts as well.