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.”