2008 represents a milestone for Sunwell Technologies Inc. of Canada as it marks 30 years since the company first introduced its Deepchill Variable State Ice technology to the fishing industry.
Deepchill is a cooling and preservation medium comprised of millions of ice micro-crystals suspended in a liquid solution to form an ice slurry. The micro-crystals surround the entire surface area of the product being cooled, giving it the ability to chill at least three times faster, and store a few degrees colder and fresher for a longer period than conventional ice. Deepchill suspends and protects the product from bruising, bacterial growth and tissue degradation.
Deepchill systems has been successfully installed onboard various types of fishing vessels around the world. The installations reveal that the Deepchill Process maintains the freshness of the fish throughout the cold chain, ensures top quality product and higher yields, which translates into higher profits.
To achieve fastest cooling in the fish receiving pond or the chilling tank, the ice concentration in the Deepchill is often set around 20%. Systems serving this purpose can be found, for example, onboard freezer trawlers of Sealord, New Zealand installed in the mid 1990s. The vessels catch hoki, a species that quickly deteriorates at higher temperatures. As with any filleting vessel, fish move through the factory at a relatively constant rate, yet they are dumped into the receiving ponds every 2-3 hours. This results in the product remaining in the ponds for several hours. Without cooling, the temperature increases and quality drops dramatically.
A Deepchill system with 16mt daily ice capacity and 4.5 m3 storage capacity was designed and integrated into the vessels' factory decks. Deepchill with 25% ice concentration is delivered into four fish receiving ponds shortly before and during catch arrival. Hoki arriving at 12-15°C is quickly cooled to 0°C. Because of the excellent preservation effect of the Deepchill the vessels are able to process product up to 18 hours old from the receiving ponds into "A-Grade" skin-off fillet, and the yield rate from the filleting machines also increases due to the firmer product being put through them. Another benefit is that the texture and colour of the fillets is much more consistent and closely resembles that of freshly caught product. During some stages of the hoki season the fish is only caught during the day, so the ability to catch larger bags at the end of the day and remain processing throughout the night without loss of quality has also proven invaluable. The Deepchill systems paid for themselves in the first six months of operation.
For fishing vessels delivering fresh fish in bins or boxes, low ice concentration slurry ice systems are not an ideal option. When icing the fish bins or boxes, the thinner slurry could easily run off through the drain holes, while a significant part of the system's refrigeration capacity is consumed to produce the large volumes of cooling water, rather than ice crystals. To address the problem, Sunwell developed a system capable of producing Deepchill in varying ice consistencies for use in fish receiving ponds and fish storage bins. Since 2001, this type of the system has been adopted onboard many fishing vessels, including Pesca Chile S.A.'s fishing fleet.
Onboard Pesca Chile's wetfish trawlers and longliners, the temperature of fish when it arrives in the receiving ponds can be as high as 15°C. Deepchill with a lower ice fraction of 15 to 20% is pumped and sprayed into the receiving ponds to immediately reduce the temperature of the large quantities of fish. The fish is kept there until it can be sorted by size and boxed. Thick Deepchill with approximately 40 to 50% ice fraction is pumped directly into the boxes leaving the fish firmly packed and cradled in Deepchill ice crystals. The boxes are kept in a fish hold for the duration of the fishing trip. Paulino Martino, Head of the technical department, confirmed: "We are pleased with the benefits of Deepchill slurry ice and the way the quality of our product has improved by using Deepchill."
One of the Sunwell's recent developments is the introduction of the world's first onboard low salinity Deepchill system for Hokubu Makiami Gyogyo Inc. of Japan in 2006. It was installed aboard its 300GT purse seiner Hokusho Maru which fishes tuna or skipjack from April to October, and mackerel and sardine from November to February.
The system has 20mt daily ice capacity and includes a compact, patented Separator/Dispenser Tank which separates saltwater from the slurry. The ability of adjusting the ice concentration up to 60% and the salt content in the range of 2 to 3% in the Deepchill ensure maximum preservation results without damage to delicate fish and avoid excessive salt uptake by the fish. According to the company's division manager, Mr Sakurai, "The fish caught can be chilled quickly onboard, so that the capacity for freshness preservation is higher, compared with crushed ice. In addition, it does not hurt the surface of the fish - also it has merit for labour saving."
Continuous innovation is the key of Sunwell's success in the industry. Two of its latest installations onboard pair trawlers Heykur and Falkur delivered to Faroe Seafood in early 2008 include a sophisticated computer based automatic monitoring and diagnostic package. A human-machine-interface with a touch panel allows operators to monitor and record the operating parameters, while office personnel can track the status of the system's operations online, and even change the system settings.
