The food and beverage giant, which pioneered low-charge ammonia systems, has added cascade and transcritical CO2 technology to the mix.
Cascade CO2 rack, which is connected to an ammonia/glycol system, at Downingtown, Pa., Pepperidge Farm plant
Like many consumer packaged goods companies, Campbell Soup Company offers numerous versions of its products, including dozens of soups and countless cookie options.
That penchant for diversity has now extended into natural refrigeration. A pioneer of low-charge industrial ammonia systems, Campbell over the past year has added two new refrigeration flavors – CO2 cascade and transcritical CO2.
In doing so, Campbell has joined a small but growing group of industrial end users who are installing transcritical and cascade CO2 systems to improve safety and avoid regulations in what has for decades been an ammonia-centric industry.
The CO2 cascade installations, incorporating ammonia (NH3) and glycol, have taken place at two of Campbell Pepperidge Farm bakeries – a replacement system in Lakeland, Fla., and a new system in Downingtown, Pa. (incorporating an unusual spiral freezer). Another replacement system is planned this year at a bakery in Denver, Pa.
The CO2 cascade solutions have so far “worked out well for us,” said Bing Cheng, Campbell’s senior manager of utilities, environmental and sustainability programs, who also serves on the IIAR’s CO2 standard committee.
In addition, at its headquarters in Camden, N.J., Campbell has deployed its first CO2-only transcritical system for a new ingredient cooler/freezer.
The CO2 cascade systems use ammonia as the primary refrigerant, which in turn chills a glycol solution; the glycol, serving as an intermediary, chills CO2. The CO2 is then delivered to the evaporators serving freezer loads.
By incorporating glycol in its CO2 cascade freezer systems, Campbell is leveraging the glycol already being used as a result of an earlier decision to replace ozone-layer-depleting R22 systems at five of its Pepperidge Farm plants (Downingtown, Lakeland and Denver, as well as plants in Richmond, Utah, and Willard, Ohio) with low-charge ammonia systems.
The bakeries – which produce such iconic brands as Milano Cookies and Goldfish crackers – are now more than 90% R22-free, said Cheng, who has overseen the transition from R22 to natural refrigerants at Pepperidge Farm.
Campbell has deviated from using a direct ammonia/CO2 cascade system (with no intermediary), an option increasingly utilized by industrial companies such as US Cold Storage and Mexican storage provider Frialsa. But in so doing, the soup company avoids having to deal with the possibility that ammonia and CO2 would accidentally mix in the heat exchanger, producing system-clogging ammonium carbamate.
With its new CO2 ventures, Campbell is adding another chapter to its pioneering career as a natural refrigerant innovator. That started in the early 1990s, when former longtime head of refrigeration Bob Czarnecki introduced one of the industry’s first low-charge ammonia designs, followed in the late 1990s with low-charge packaged ammonia units. Most of Campbell thermal plants (which make soup, sauces, beverages and other products) emphasize low-charge ammonia chiller packages circulating glycol.
Starting in Lakeland
Campbell first CO2 cascade project took place in 2017 at the Lakeland, Fla., Pepperidge Farm facility as it underwent its conversion from R22, which was replaced by ammonia/glycol for HVAC and chilled water applications.
“We included enough capacity in that new system for a CO2 skid,” which serves a small formerly R22 ingredient freezer, said Cheng. “CO2 is better for low-temperature applications” than glycol, he added. The cascade system was provided by engineering firm CRT Design, Jacksonville, Fla.
The same approach will be followed in the early spring of 2019 at the Denver plant, though the CO2 rack (from Zero Zone) will be located on the roof rather than in an engine room. “The load at Denver was remote enough [from the engine room] to put the CO2 skid out there,” said Cheng.
The cascade systems at both Lakeland and Denver serve small ingredient freezers (7.2 TR and 6 TR, respectively), with CO2 evaporators in the rooms.
Because of ammonia’s greater efficiency, Campbell normally uses it for freezers, but “it would not make economic sense to put in a low-temperature ammonia compressor and penthouse ammonia evaporator for that small a load,” said Steve Parra, a senior engineer for Campbell based, like Cheng, at its Camden, N.J., headquarters.
Campbell does employ a direct ammonia system with a penthouse evaporator in freezers at its thermal plants and at a Pepperidge Farm facility in Richmond, Utah. “We use a slight overfeed on the coil because we’re trying to reduce the amount of ammonia,” explained Parra. “We build them in a penthouse and elevate the coils enough to drain freely to the engine room.”
For safety reasons, he added, “we don’t like flooded coils in the plant.” This is also one of the advantages of using CO2 in a freezer application rather than ammonia. “If you blow [a CO2] evaporator unit in the freezer, there’s not the potential for a dangerous situation,” he said.
A lesson learned from the initial Lakeland cascade installation, which was delayed due to contractor issues, was the importance of hiring a contractor who is “familiar and comfortable with CO2 systems,” said Cheng. For its succeeding CO2 projects, Campbell has employed Jax Refrigeration, Jacksonville, Fla.
For maintenance, Campbell uses its own technicians (such as in Downingtown) or a third party (Capital Refrigeration and Sodexo in Camden). Hillphoenix did initial training on its CO2 technology at Downingtown and Camden.
For CO2 racks in both transcritical and cascade systems, it’s important to train the maintenance staff to remove all moisture from the system if the system is recharged with CO2 and to use only “Coleman grade” CO2 gas, noted Parra.
Spiral CO2 freezer
At its Downingtown, Pa., Pepperidge Farm frozen-food plant, Campbell installed a new 110-TR spiral production freezer (including evaporator coils) for bread products in January 2018. Cheng believes this is one of the first freezers in the U.S. bakery industry to use CO2 in the freezing unit, said Cheng. (In Canada, Wholesome Harvest Baking has installed a Mayekawa NewTon NH3/CO2 packaged system that serves a spiral bread freezer.
The CO2 spiral freezer is connected to a CO2 rack (from Hillphoenix), which is in turn linked to an existing ammonia/glycol system to create the cascade system. “There was extra glycol capacity that we tapped into for the CO2,” said Cheng.
Utilizing already existing ammonia/glycol equipment at the Downingtown plant again made the cascade system “a very low-cost option” compared to adding an penthouse ammonia evaporator, Cheng noted. For its Pepperidge Farm freezers, “we could have used penthouse ammonia or HFCs, but we thought [cascade CO2] was the best balance between natural refrigerants and cost.”
Campbell may install another CO2 cascade system at a Pepperidge Farm facility in Downers Grove, Ill., that was converted in 2004 from R22 to mostly R507. “It sits in the middle of a residential neighborhood, so we can’t have ammonia there,” said Parra. The cascade system using secondary glycol would replace the remaining few R22 compressors.
Parra said he was pleased thus far with the performance of the CO2 cascade systems. “We would use it again,” he said. “It’s a perfect fit for smaller loads where we don’t have low-temperature ammonia systems.”
After start-up, Campbell has not experienced CO2 leaks in the cascade system, noted Parra. The efficiency of the cascade system takes a “little hit” compared to a direct ammonia system, noted Parra, but he did not consider it significant for “relatively small loads.”
At its Pepperidge Farm facilities in Richmond, Utah, and Willard, Ohio, Campbell has transitioned to ammonia/glycol but has not yet installed CO2.
In Camden, N.J., at its world headquarters, Campbell installed its first transcritical CO2 system (from Hillphoenix) in the first quarter of 2018 for a new 30-TR soup-ingredient cooler/freezer.
Camden is largely a research-and-development facility that occasionally does small manufacturing runs for test markets. In 2017, Campbell installed a 4.4- megawatt solar array at its headquarters, the largest in Camden, N.J. It was designed to generate the equivalent of 20% of the headquarters’ electricity demand.
Campbell does not use ammonia in New Jersey due to the onerous regulations the state places on industrial users of the gas, said Parra, adding that the company does not want to use ammonia in any event at its headquarters. An R410 glycol chiller in Camden was too small to serve the new freezer, he said.
In terms of efficiency, the transcritical system offers the advantage of using a single refrigerant and not having to pump secondary glycol or use heat exchangers between refrigerants, as in the cascade systems. On the other hand, transcritical loses efficiency while operating in warmer ambient temperatures. Campbell did not choose to use an adiabatic condenser or other add-ons to improve efficiency.
Overall, though, Cheng has been satisfied with the energy performance of the transcritical system over its first year of operation. “We definitely didn’t see a large spike in energy use” after adding the system, he said. For the capacity being served, the energy penalty for the transcritical system was small, added Parra. “It did not make a big difference in our decision.”
As a company, Campbell said in its 2018 Corporate Responsibility Report that it believes the use of natural refrigerants “significantly improves energy efficiency, lowers energy costs and reduces GHG emissions.”
For Parra, transcritical was “the best way from an economic standpoint, both capital and installation. And it runs nice.”
Cheng concurs that the transcritical system is reliable and “maintenance- and operations-wise, it functions pretty well.” After some initial tweaking in the first month, the system has not experienced a leak, he said.
Challenge of remote units
While most of the R22 HVAC units at Pepperidge Farm plants have been replaced by ammonia/glycol chillers, there were some small remote units, roughly 20-30 TR in capacity, for which “it did not make economic sense to run glycol across the roof from a central system,” said Parra. They have so far been replaced with R410 units.
“Eventually the R410 units will get replaced,” said Cheng. “We’re trying to figure out if it’s worth expanding the existing [ammonia/glycol] system to cover it.”
However, for a much larger (300-TR) load at a thermal plant in Napoleon, Ohio, Campbell installed a air-cooled ammonia chiller from Azane that produces cold glycol used by an air handler to generate air conditioning. “There was nothing else on that side of the plant,” said Parra. “So we put the Azane unit there.” “It made more sense to drop [the Azane unit] in,” said Cheng. “It’s working fine.”
In general, Campbell's operating guidance is “to remove HFC whenever possible,” said Parra. (Campbell has to date not used HFO blends.) That guidance stems from Campbell participation in the Consumer Goods Forum, which has pledged as a group to phase out HFCs and transition to climate-friendly refrigerants.
“We’re still committed to our Consumer Goods Forum’s commitments,” said Cheng.
And Cheng, who last year added management of environmental and sustainability programs to his title, is committed to achieving sustainability goals established by Campbell, not only in refrigeration but also water usage, overall greenhouse gas emissions and waste reduction. “It’s a passion of mine,” he said.
To read the complete original article on Campbell Soup in the February issue of Accelerate America, click here.
“We could have used penthouse ammonia or HFCs, but we thought [cascade CO2] was the best balance between natural refrigerants and cost.”
– Bing Cheng, Campbell Soup