Keeping fish fresh with slurry ice

GERMANY/ICELAND: Bitzer Ecoline tandem compressors are playing their part in extending the shelf life of fish for an Icelandic fishing company.

The compressors, supplied by Bitzer’s Reykjavik-based partner Vörukaup, are used in slurry ice machines produced by Icelandic producer KAPP. 

In a recent project, KAPP was asked to come up with a solution for a fishing company who needed a land-based installation that could process 300 tons of fish per hour. The initial temperature of the fish is about 4°C when it arrives at the fish factory and the goal was to take it under 0°C as fast as possible.

Slurry ice technology was considered the right choice for this project because of its rapid and efficient cooling capabilities. KAPP’s solution was the OptimICE BP-140, a variable solution that can be used on both land and vessel installations. It has an output ranging from 1,780 l/h with 40% ice concentration to 3,650 l/h with 10% ice concentration.

Slurry ice is a mixture of seawater and ice produced from the sea on board the ship. This is sprayed over the freshly caught fish to cool it down within an hour to about -0.5°C, keeping it that way without it freezing.

The quick cooling process increases the shelf life of the fish and minimises the formation of microbacteria. In this way, the fish keeps its shape and is fresh when it reaches the end consumer.

“Our focus is on keeping the temperature as low as possible throughout the production process. The slurry ice is produced and processed on board the ship directly from the seawater, and then pumped over the fish from a hose. It couldn’t be simpler or safer. With the slurry ice technology, we can help the fishing industry extend the shelf life of fish by five to seven days,” explained KAPP chairman Freyr Friðriksson.

In order to cope with the large number of fish that needed to be processed, KAPP delivered four land-based units of OptimICE BP-140 slurry machines. These were accompanied by reservoirs – in this case, four storage tanks. Each tank can deliver several cubic metres of slurry ice per hour. The company also bought two OptimICE slurry ice machines for their vessels. With the OptimICE, the temperature of the fish reaches -0.7°C within an hour and stays at that temperature for the whole production time.

Each slurry ice machine is equipped with a Bitzer Ecoline tandem 66FE-88Y-40P compressor with factory-mounted CRII, Varistep capacity control, Delta-PII and crankcase heater on both compressors, as well as a Bitzer horizontal receiver F562N. The units for the vessels are additionally equipped with a seawater-cooled Bitzer horizontal condenser K1973TB.