CO2 finding more applications in the industrial sector

Carbon dioxide, which is making progress as a refrigerant in the North American supermarket sector, is also increasingly infiltrating its way into the industrial sector in cascade and secondary systems, which was evident at the IIAR (International Institute of Ammonia Refrigeration) 2015 Conference & Exhibition, which took place in San Diego from 22-25 March.

At the IIAR 2015 trade fair and conference much of the talk was about the incorporation of CO₂ into cascade and secondary systems in concert with ammonia, as well CO₂ transcritical systems, which are being used to replace HFC systems in smaller facilities. In larger plants, the NH₃-CO₂ systems enable end users to reduce their ammonia charge and limit it to the machine room, thereby increasing safety and reducing regulatory burdens.

Suppliers of supermarket systems make headway with industrial sector

Quebec-based Carnot Refrigeration discussed its ammonia-carbon dioxide and CO₂ transcritical refrigeration systems at the IIAR show.

Known for its transcritical CO₂ systems for supermarkets, Carnot has two DX NH₃-CO₂ cascade systems with hot-gas defrost and heat reclaim installed in industrial settings as well as a transcritical industrial installation on the way, said Tommy Dolbec, design engineer for Carnot.

In Canadian warehouses, we need heat reclaim applications for heating the shipping docks and higher-temperature rooms,” said Dolbec. The NH₃-CO₂ systems also enable end users to reduce their ammonia charge.

In general, Carnot recommends NH₃-CO₂ for larger facilities and CO₂ transcritical for smaller ones (under 100,000 square feet or 9,290 m²).

Hillphoenix – also known for its extensive installations in supermarkets – was at the IIAR show discussing the opportunity to use its transcritical CO₂ racks in small warehouses.

Hillphoenix has installed one such system in a pharmaceutical facility and another in a produce storage warehouse in Canada, said John Gallaher, vice president, industrial applications, declining to name the companies without their permission. Industrial refrigeration end users are now more open to considering transcritical systems, particularly as an alternative to HFC units, he added.

Zero Zone continues to pursue applications for CO₂ refrigeration in both the supermarket sector (which comprises 75% of its business) and industrial settings, noted Dan O’Brien, vice president of sales and manufacturing for Zero Zone, North Prairie, Wis.

For example, this week, Zero Zone’s first transcritical CO2 system goes live at a commissary in a pharmaceutical facility for both low- and medium-temperature applications.

At the supermarket level, Zero Zone has supplied an ammonia-CO₂ skid to a Whole Foods store opening in Dublin, California, in June; it contains 300 pounds (136 kg) of ammonia, confined to the roof. The first cost of the ammonia-CO₂ system is higher than that of a conventional system, but it offers the possibility of energy savings, he added.

In the future we expect to do ammonia-CO₂ in industrial plants,” O’Brien said, adding that this would decrease the ammonia charge compared to ammonia-only systems. “We had to put our toe in the water before jumping in.”

Vilter Manufacturing, a division of Emerson Climate Technologies, is developing screw and reciprocating compressors for transcritical CO₂ applications in industrial plants.

CO₂ is on our radar,” said Tom Melotik, district sales manager for Vilter. “There’s not a lot of CO₂ [refrigeration] in the U.S., but it’s starting to grow, even at a conference like this.”

Cimco offers range of CO₂ products

As a large designer, builder and contractor, Cimco Refrigeration elicited a lot of interest at its booth in Mayakawa’s NewTon ammonia-CO₂ unit following a presentation on CO₂ given by its director of business development, Benoit Rodier.

CO₂ is starting to perk up in industrial and recreational (ice rinks) in the U.S.,” said Jose Mergulhao, vice president, US operations for Cimco. “NewTon is one of the pieces – a small dedicated package built for smaller facilities, maybe 5,000 to 10,000 square feet (465 – 929 m²) with three evaporators.

Cimco also supplies subcritical and transcritical CO₂ systems, mainly subcritical with low-charge ammonia in industrial settings. “It’s a key selling point that we can get a new facility under 10,000 pounds of ammonia by using CO₂,” he said.

Westermeyer gauges contractors’ CO₂ needs

At the IIAR show, Adam Chapman, area sales manager, Westermeyer Industries/Mueller Industries Climate Group, was able to confer with contractors about their needs in regard to incorporating CO₂ into industrial systems.

These guys handle ammonia, but that doesn’t run at the high temperatures of CO₂,” he said. “So we need to educate them on CO₂ and gauge what they find difficult about it and what they need. Do we need to change our products to meet their needs? Ultimately, CO₂ [adoption] hinges on contractors being able to service them.”

In the CO₂ area, Westermeyer supplies oil separators and accumulators while Mueller offers CO₂ ball valves.

M&M cuts ammonia charge in cascade system

M&M Refrigeration designs complete systems for industrial end users, about 75% of them ammonia-CO₂ cascade models. “We’re seeing more interest in ammonia-CO₂ cascade to get the charge down,” said Ole Christensen, vice president, engineering.

In its cascade systems, the ammonia charge is 15% to 20% of what it would be in an ammonia-only system, Christensen said. In one 700,000-square-foot cold storage facility, the ammonia charge in a cascade system is less than 8,000 pounds while the CO₂ charge is 60,000 pounds. “None of our CO₂ installations have more than 10,000 pounds (4,536 kg) of ammonia,” he noted.

In addition, Isotherm, Arlington, Texas, offered its water-cooled condensers or liquid chillers for low-charge ammonia-CO₂ cascade systems. “There’s an extremely limited charge of ammonia – 2-3 pounds per ton,” said David Boldrick, sales manager.

Industrial trainer provides perspective on ammonia-CO₂ systems

Jeremy Williams, directing manager/lead instructor for Garden City Ammonia Program (GCAP), is well positioned to observe trends in the industry, given his company’s longtime position as a training school for industrial refrigeration, particularly systems using ammonia and carbon dioxide. The school trains about 2,400 students per year.

For example, he sees interest in ammonia-CO₂ systems for new facilities that reduce the ammonia charge compared to traditional systems. Guys want to keep ammonia in the engine room and CO₂ in the plant,” he said at his IIAR booth. But the change from large-charge ammonia systems will not happen overnight. “It will take 30-40 years to get to that in all new plants.”

In the meantime, he does not expect existing ammonia plants with, say, 350,000 pounds (158,757 kg) of ammonia and 48 screw compressors, to get under 10,000 pounds (4,536 kg), the threshold for PSM (process safety management) plans. He also doesn’t believe the industrial sector will gravitate to CO2-only systems. “Industrial means killing 20,000 hogs a day,” he said. “Ammonia is better than CO₂ for that.”

Still, he acknowledges that many industrial operators are keen on reducing the risks posed by large quantities of ammonia. “Safety is huge and government regulations are huge,” he said. “To reduce risk with lower charges is one option, but it won’t work for everybody.”