ORLANDO, Fla. — More than half of U.S. commercial building space is cooled by packaged HVAC equipment, according to the U.S. Department of Energy (DOE). Additionally, existing rooftop units consume more than 1.3 percent of the country’s annual energy usage. It’s no surprise the biggest trend driving the rooftop market is efficiency.


Customers, utilities, and design engineers are emphasizing increased energy efficiency, according to Mike Ray, director, commercial rooftop units, Lennox Intl. Inc.

“As much as 80 percent of the market is emergency or design-build replacement, so offering high-efficiency products that can fit on existing roof curbs is important,” said Ray. “Additionally, the emphasis has been on the development of retail buildings in urban areas. This being the case, building owners are interested in reducing the amount of sound from the air conditioning equipment on the roof.”

Lennox showcased its Energence Ultra High Efficiency packaged units at the AHR Expo in Orlando. The equipment is now available in 3- to 6-ton sizes, bringing the lineup to 3-20 ton. The units feature up to 23.5-SEER, 15-EER, and 22-IEER ratings. The high-efficiency units save money by reducing energy usage during part-load conditions, where units operate most of the time. They also operate as quietly as 73 dBA, feature a patented Humiditrol® dehumidification system that allows for independent control of temperature and humidity, include a foil-faced insulation on all internal surfaces that helps minimize airborne fibers and improve IAQ, and offers an optional energy-saving SmartAirflow™ system. Additionally, Energence units are Energy Star-qualified and exceed ASHRAE 90.1-2010 minimum standards.

The new 3- to 6-ton units feature a variable-speed compressor with inverter, a variable-speed blower, and a variable-speed condensing fan motor. These components modulate to match the space temperature requirements, providing improvements in comfort and energy reduction.

“Energence is ideal for environments, such as but not limited to, schools focusing on IAQ, dehumidification, comfort, and energy efficiency,” said Ray. “The units can be applied in either new construction or replacement markets, as they were designed to fit many existing Lennox curbs. Design emphasis was placed on addressing the growing needs of the replacement market and minimizing the size and weight of these new models.”

Petra Engineering Industries Co. displayed its 100 percent Make Up Outside Air Cooled Rooftop Units, which range 3-30 ton, with Air-Conditioning, Heating, and Refrigeration Institute (AHRI) efficiency up to 16 EER. The units provide multiple added benefits to customers, including quieter volumes, a compact footprint, a recovery option, and accessible components. The compressors and refrigeration components are allocated in a spare compartment with 2-inch double-wall panels that include full access doors or removable panels. This enhances sound dampening for the unit. They also feature an energy recovery solution, which meets ASHRAE ventilation and energy standards, improves IAQ, and reduces total HVAC equipment capacity.

“Globally, we’re seeing a trend for green — a trend for efficiency — and better, longer-lasting equipment at reasonable prices,” said Rami Al Suleiman, Americas sales manager, Petra Engineering. “Our equipment fits the needs of the client and the consultant. We provide a better efficiency than is required in the market. Higher efficiency is a benefit for the end user. It means better air quality, improved control, and less energy consumption.”


The rooftop market is seeing further interest in integrating equipment into the building system, according Eric Newberg, director of commercial product management, unitary products group, Johnson Controls Inc.

“Integrating the equipment into the building system improves overall efficiency and offers better comfort for occupants,” Newberg said. “Integration into building management systems is critical to accomplishing this and such technology is becoming more mainstream.”

Johnson Controls featured its new controls technology that is being used in all of its commercial rooftop equipment at the AHR Expo. The Simplicity Smart Equipment Controls (SSE) system provides easy integration into most building automation systems (BAS) as the controls are native BACnet, but can be converted to ModBus or the Johnson Controls’ N2 language. The controls feature an LCD screen that scrolls plain text to communicate settings and other programming points.

“We also have a device called the Mobile Access Portal (MAP) that provides a wireless connection into our control system,” Newberg said. “Now, any smart device can be used to gain access to the power within the SSE Controls. The MAP has many access points to the rooftop. It can be connected to the rooftop directly, wired into the communication bus, or plugged into a network sensor in the building space. The versatility is key to allowing the contractor, engineer, or maintenance professional access to the control system at whatever point best suits them. We have also added Fault Detection and Diagnostics (FDD) to all rooftop equipment, which provides guidance on maintaining optimal performance of the equipment to whoever is performing the maintenance. This will extend the life of the product and assist in keeping the equipment operating at peak efficiency. When included with MAP, FDD makes smart devices, such as a smartphone, the most critical tool a contractor will bring to work.

“The SSE Controls are the key to integration of rooftop equipment into building automation systems to support smarter buildings,” he continued. “All rooftop units produced with SSE will be easily connected to BAS systems with the addition of a communication card. The equipment will be ready now when the decision is made to move to BAS in the future for existing buildings.”


On Dec. 17, 2015, the U.S. Department of Energy (DOE) finalized new negotiated energy conservation standards for commercial air conditioners and heat pumps and commercial warm-air furnaces, otherwise known as rooftop units (RTUs). According to the DOE, the new efficiency standards for RTUs will save businesses as much as $167 billion in energy costs over the lifetime of the equipment — more than any other efficiency standard issued to date.

The new RTU standards will take 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 as a unit with a commercial air conditioner also become effective in 2023.

“We’ve been working closely with the DOE to develop standards that are appropriate and cost-effective,” Ray said. “The Energence units exceed what the DOE requires, but we’re continuing to work closely with the DOE. We’re very concerned about striking a balance between energy efficiency and cost-effectiveness. We want to make sure the efficiency standards that are developed are fair for all parties involved, including the building operators.”

John McKissack, commercial product manager, Nortek Global HVAC LLC, said the new efficiency standards are not going to be easy to achieve.

“Everybody’s chasing this next round of efficiency in the marketplace that the DOE has put down in front of us,” McKissack said. “Where we are today for minimum efficiency and where we have to be in 2023 represents a 30 percent increase in efficiency — that’s not easy to achieve. It’s one of the biggest challenges and trends hitting the light commercial market today. This efficiency, mandated by the government, is going to impact everything throughout the chain. It’s going to influence things like the weight loading on the roof. When you have to replace one unit with another unit, the new unit being 30 percent more efficient is probably going to carry 30 percent more weight eventually. So, that has to be looked at to make sure the roof can structurally support it.”

Regulatory-driven efficiency is driving the rooftop market, said Mitul Lakdawala, product manager, VRV and light commercial products, Daikin North America LLC. “The high-efficiency trend will certainly grow,” he said. “The DOE is trying to show the savings to the owners and the high-efficiency market. Increasing the efficiency helps the industry overall.”


The new rooftop standards hitting the market in 2018 and 2023 are not the only challenges the industry will face in the future.

“There is also a refrigerant change in our future to resolve the high GWP [global warming potential] of R-410a,” said Newberg. “This could be seen as soon as 2023, as well. Product platforms have to stay flexible to adapt to an environment of continuing energy-efficiency increases. Controls and variable-speed systems will play a critical role in this.

“We’re going to spend a lot of time creating the architecture for the right product mix to satisfy our customers,” he continued. “Some of the requirements are efficiency only, but there are other ASHRAE 90.1 requirements that require two-speed fan operation. Those two things don’t always work together well. And, some states don’t even require it. It’s going to add complexity to our product mix, and it’s going to force us to really look at pricing and cost optimization, so we put the best product forward for all of the specific customer applications. When you get to 2023, it’s such a significant jump in efficiency, plus the potential of adding in a refrigerant change, that it’s going to affect 80 percent of our product line. So, we’ve got roughly seven years to go through hundreds of refrigeration systems and bring them up to the new efficiency standards. The cost is going to be significant.”

Publication date: 2/22/2016

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