Refrigeration Trends Focus on Efficiency, Eco-Friendly Systems, Preserving Catch Quality

Marine Refrigeration Solutions worker Doug “DC” Cannon at work on a system aboard a boat. Photo courtesy of Marine Refrigeration Solutions.

Modern, eco-friendly and consumer-focused solutions are making their way into the marine refrigeration industry, while old processes are on the chopping block. Industry insiders say they’re seeing trends aimed at automated efficiency, reducing environmental impact and systems that better preserve catch quality.

It’s important to keep up with technology and trends, said Lars Matthiesen, president and mechanical engineer for Highland Refrigeration, a Seattle-based company that designs and manufactures marine and industrial refrigeration systems.

At Highland Refrigeration—a small company of about 25 people, including a handful of refrigeration engineers—they utilize worldwide connections to stay current with the latest industrial and technical developments, including safety and energy-efficiency standards.

“We see the need for a product that doesn’t exist,” Matthiesen said in an interview. “That’s how we stay in front of the game.”

New tech is sometimes slow to be incorporated for maritime vessels and when it does, it needs to be tested thoroughly before application, explained Doug “DC” Cannon, owner of Marine Refrigeration Solutions, which specializes in installing, servicing, troubleshooting and repairing marine refrigeration, primarily on the West Coast and in Alaska.

“The commercial fishing fleet tends to be very traditional and is 15-to-20 years or more behind latest technology developments, mostly because if it ain’t broke, why fix it,” Cannon shared in an email interview.

For example, the adoption of semi-hermetic sealed compressors without shaft seals has been one of the biggest industry changes since the 1970s, he noted. Even so, there are still plenty of vessels that are just now bringing some 1990s-era technology into the game.

Support technologies have to be proven reliable before they are adopted throughout the fleet, Cannon explained.

“There’s a lot to be said for something manual that you can jury-rig to get you up and running,” he added.

An RSW system with CO2 flooded chiller ready for installation on a trawler. Photo courtesy of Highland Refrigeration.

Cannon shared another example, noting that many larger marine refrigeration systems still just have mechanical gauges with dual pressure switches, designs which haven’t changed much since the 1940s or 1950s. Due to the complexities, the adoption of Programmable Logic Controllers (PLC), which has happened in other industries, is something the marine refrigeration industry is just beginning to look at implementing. 

As industry leaders adopt new technology, they make the most of it for their unique applications.

Teknotherm CEO/President Osman Colak said in an email that a recent trend in the marine refrigeration industry is a focus on continuous improvements on automation, PLC control and remote monitoring and analysis. Teknotherm, a Seattle-based designer and manufacturer of marine and industrial refrigeration systems, utilizes PLCs in most of its control panels, he noted.

It’s a balance between keeping the system easy to use and making the most of modern tech, Wally McDonald, owner of Alaska-based Fleet Refrigeration, which designs, installs and maintains refrigeration systems for fishing vessels and the seafood industry, said in an interview.

Most of his customers at Fleet Refrigerant have 50-foot vessels and don’t want overly complex systems with too many moving parts that might be subject to failure, he noted. But at the same time, he said that most modern technology is so reliable now there’s no reason not to take advantage.

“What we’ve done over the years is taken advantage of some technological advances,” McDonald said. “But my theory is you want to keep it fairly simple.”

Natural Refrigerants, Less Environmental Impact

“We can’t overlook the elephant in the room, which is global warming,” Matthiesen said.

Refrigeration, by nature, can’t be totally carbon neutral, he explained. But considering the entire vessel, propulsion produces a lot more carbon than refrigeration.

Everything has an impact although seafood, like mussels and oysters, leaves a lower carbon footprint than the production of other sources of protein, like beef or chicken, Matthiesen pointed out. It might eventually be listed on food packaging, alongside nutrient information, he predicted.

“I think we’ll see more growth in that,” he remarked.

McDonald agreed that the environmental impact of the refrigerant system is relatively small compared to the overall vessel, but said the marine refrigerant industry absolutely has to evolve with the awareness of environmental impacts.

When he started in the marine refrigeration industry more than 30 years ago there wasn’t much concern—or even known—about the Ozone Depletion Potential (ODP), McDonald recalled. But through the international agreement, the 1987 Montreal Protocol on Substances that Deplete the Ozone Layer, the U.S. committed to an effort to regulate and phase out ozone-depleting substances.

And as systems starting switching over, more information was discovered about refrigerants that have Global Warming Potential (GWP).

R22, a historically common type of freon refrigerant for marine vessels, is now facing more restrictions, causing the price to sharply increase. The Environmental Protection Agency banned importing or manufacturing new equipment that contains R22 a few years ago. After 2020, only recovered, recycled or reclaimed supplies of R22 have been available.

As the EPA cracks down on refrigerants with a high GWP score, common refrigerants like R22 and R507, a blend of hydrofluorocarbon (HFC) refrigerants, either have already stopped production or are being phased out, Cannon noted. 

“Most units in Bristol Bay, for instance, are charged with one of these two refrigerants. Consequently, the price of these refrigerants has skyrocketed in the last few months and will continue to do so, as they become more difficult to source,” Cannon said.

An RSW system with CO2 flooded chiller ready for installation on a trawler. Photo courtesy of Highland Refrigeration.

The effort is now focused on natural refrigerants with low ODP and GWP and reducing consumption in phases.

Europe is already using natural refrigerants as alternatives in systems, but the U.S. is reluctant to accept it, Matthiesen said.

“Natural refrigerants are coming,” he said, noting that it’s already happening around the globe. “That’s what we see the trends dictated by … and that’s where the trend is headed in the U.S.”

It can be a difficult and slow process, he noted, but progress is taking place.

Natural refrigerants, like R717 ammonia, R290 propane and R744 CO2 (carbon dioxide), with reduced ozone depletion factors are definitely on their way in, Matthiesen said.

Phasing out ozone depleting refrigerants and switching to natural refrigerants, like ammonia (NH3) and CO2, is an important issue in marine refrigerants right now, Colak noted.

As previously common refrigerants like R404A and R507A are being phased out, new alternatives like R448A/R449A are being used as replacements for direct expansion systems. The temperature glide though makes them unsuitable for flooded systems, he said.

Cannon noted that some of the new refrigerants, like R448 or R449, which combine HFC and hydrofluoroolefin (HFO) components, have similar performance and temperature curves to R507, but their environmental impact score is lower, making them “EPA favorites.”

At Fleet Refrigeration, they’ve used R507 in systems, but started switching over to 448A in 2021.

“Now we’re going a step farther with the R448A, which is the most prominent right now,” McDonald said. “We started putting in a couple (448A) systems last year.”

It might be a little less efficient, but not enough to be notable—a one- or two-percent overall difference, he explained.

“It’s working fine and eventually the cost will start coming down,” McDonald said.

The cost for 507 has gone up as well because it’s also recently “gotten into the crosshairs” of the EPA regulations, in terms of GWP, McDonald said.

CO2 is also making a “resurgence,” particularly in low-temperature systems, Colak commented.

There’s been progress in developing less complex controls and better support for the high-pressure operating system it requires. Other businesses, like grocery stores, have made the change and the commercial fishing industry is looking toward that transition as well, Colak said.

Highland Refrigeration has recently been using CO2 in several systems.

Carbon dioxide is natural, has few-to-no ozone depletion effects, is inexpensive and has no odor, Matthiesen noted. It was initially used about a century ago, in expensive high-pressure compressors and it was eventually replaced by ammonia. Nowadays, people don’t want to be around ammonia because of the potential health and safety issues, both of which can present a liability concern.

Working once again with CO2 as a refrigerant has some benefits with modern technology, like the use of high-pressure rated components, stainless steel piping and new, reliable semi-hermetic compressors without shaft seals, Matthiesen explained.

“We are using it in parallel with other systems,” he said. “Not saying this is what everybody should do, it depends on your ultimate goal.”

It depends on the customer and their needs, as well as the specific environment where the system will be installed. Highland Refrigeration recently outfitted a compact transcritical 120TR RSW system using CO2 on a 148-foot trawler owned by Global Seas. The vessel operates in the Bering Sea in Alaska.

A recent marine refrigeration operator class. Photo: Marine Refrigeration Solutions.

CO2 is widely used in maritime and other industries, but that doesn’t mean it’s without its challenges, Matthiesen said.

“It’s not completely innocent,” he said.

There’s no smell, color or taste, so human senses can’t detect it or tell if it displaces the air indoors and builds up to dangerous concentrations.

CO2 is a fine refrigerant, but it operates at very high pressures and takes special equipment, McDonald said. He hasn’t quite noticed a trend of using CO2 aboard smaller vessels. He’s unsure if, on a 58-foot vessel for example, its applicable just yet, although it may be in the future.

There is talk about more ammonia systems, also a great refrigerant, McDonald said, but on 58-foot vessels, again as an example, it has potential safety issues that freon doesn’t, he noted.

“It can have nasty stuff when it leaks,” McDonald said.

Still, despite its bad reputation, ammonia is a natural refrigerant, efficient, inexpensive and environmentally friendly, Colak said.

Focus on Freshness

The inherent problem of fish is that it starts degrading as soon as it’s taken out of the water, Matthiesen said.

“It will deteriorate no matter what you do,” he explained, “so you do everything you can to slow it down.”

Using 32°F (0°C) chilled fresh water for food processing is a trend starting to pick up momentum as part of this effort.

“In the quest for maintaining seafood freshness, (and thereby quality) there is another improvement we see being used more and more,” Matthiesen said. “That is the introduction of chilled fresh water for processing equipment and for product glazing (ice coating) of seafood to be frozen.”

If the seafood has been properly chilled and arrives at the processing facility at approximately 32°F, it is important to keep it at that temperature during processing, he explained.

Even brief exposure to city water at temperatures that can reach 60-70°F (16-21°C) can wake up bacterial and enzyme activity on the product surface. This may happen through filleting and cutting machines or with manual gutting, where water is used to clean the fish cavity.

Only the hardiest bacteria can survive the cold, and warm water helps bacteria flourish and speed up deterioration, Matthiesen said. That’s why chilling water used in production is recommended.

“It makes sense to keep the water, and everything that has to do with the product, at a lower temperature,” he said. “Some companies have already implemented that in their plan.”

Keeping the temperature cold throughout the process will also reduce freeze time or minimize ice melting if it’s only going to be kept chilled.

Highland Refrigeration has developed some equipment to combat this issue. Fresh water at 32°F is produced in a stainless-steel heat exchanger by means of either a stand-alone air-cooled refrigeration plant or hook up to an existing refrigeration system. The chiller can work with any refrigerant. In some cases, the chilled water system is delivered with an ultraviolet (UV) water sterilization system for independence from chlorinated city water systems.

The unit can be mounted remotely from the processing line, hooked up with a pump circulated water system, ensuring that all water is continuously being chilled to the optimal temperature.

There have also been studies and improvements in low-charge systems, Colak noted. This means systems using less refrigerant load while providing high performance, he explained.

Recent studies show that frozen-at-sea fish keep its taste and nutrient content in the best condition, Colak said. Consumers want easy access to seafood and that’s changing the habit of sourcing frozen products due to easy distribution and good quality, he explained, but it doesn’t have to be frozen at below-minus temperatures before reaching the consumer.

Teknotherm’s RSW systems keep it just above freezing and fresh as possible as the catch is brought shoreside, Colak explained.

Workforce, Automation and Efficiency

Rising costs and dwindling availability of personnel willing to work in the food industry have made investment in automated food freezing equipment a necessity, Matthiesen said. It also results in a more streamlined process, he added.

Highland Refrigeration supplies semi- and fully automatic plate freezers, both horizontal and vertical, for integration in plants onboard factory vessels and ashore. Also, belt type and spiral freezers are being installed in fish processing plants, mostly for freezing of portioned and/or semi-prepared products.

“The labor costs can be reduced to a fraction of the cost of a manually operated freezer, and needed floor space, handling and clean up time can be greatly minimized, as well,” Matthiesen explained.

Working in isolated locations with limited access to the workforce can be challenging, Colak noted. To combat this issue, Teknotherm also developed automated systems.

The majority of the company’s control panels utilize PLC, based on size reduction, ability to provide extensive information about past and present system operations and easily changed options. Vessels can maximize performance and easily keep a temperature record for the product using PLC-based controls, Colak explained. They’ve also incorporated remote control and Wi-Fi connections.

In terms of efficiency, Fleet Refrigeration often is relying on soft-start systems, so instead of the compressor using a “massive electrical draw to get it started, it kind of ramps up,” McDonald explained. It’s also easier on the generator sets, he added.

They’re also seeing more variable frequency drive motor systems, McDonald said.

“You can control the pressures just by speeding and slowing down the motor,” he explained.

It’s popular now in larger refrigerant systems, particularly for grocery stores and air conditioning. The compressors don’t “slam off and on,” he explained.

“For those applications it’s great,” he said. While it has its applications on boats, “at the same time there’s a little bit more complexity.”

Shore-based applications are plugged into power grids, leading to concerns about kilowatts and costs.

“On a boat, you got the genset running—period. So it’s not so much of a concern. You don’t have to get quite the level of efficiency for power consumption,” he said.

Looking Ahead

“Looking to the future in our industry, as new refrigerants are phased into use and systems become more complex as new technologies are gradually adopted, the need for good operator training increases every year, putting more and more pressure on operators to understand how to use their equipment effectively,” said Cannon, who has been in the industry for more than 25 years.

That’s especially true for the Bristol Bay fleet, as the short season in the area makes sourcing adequate support services difficult. For a few weeks in June, 10 to 20 marine refrigeration service technicians are desperately needed for support. But there’s not enough work for that many full-time technicians the rest of the year, Cannon noted.

“This puts a lot of pressure on the fishermen themselves to understand their systems, as tech support is limited,” he said.

Marine Refrigeration Solutions offers operator classes specifically geared toward fishermen in an effort to meet this need.

“We teach them to operate their refrigeration systems with confidence,” Cannon said.

McDonald said he’d like to see the industry focus on more user-friendly systems.

“The guys are out there to fish, they shouldn’t have to be fiddling around with their refrigeration system trying to figure out how it works,” he remarked. “That’s what we try to come up with in our systems.”

Sara Hall has 15 years of experience at several regional and national magazines, online news outlets, and daily and weekly newspapers, where coverage has  included reporting on local harbor activities, marine-based news, and regional and state coastal agencies. Her work has included photography, writing, design and layout.