Reports

Increased value of pelagic species - FINAL REPORT / Increased value of pelagic species

Published:

01/05/2011

Authors:

Lárus Þorvaldsson, Björn Margeirsson, Ásbjörn Jónsson, Sindri Sigurðsson (SVN), Ásgeir Gunnarsson (SÞ), Sigurjón Arason

Supported by:

AVS Fisheries Research Fund

Contact

Sigurjón Arason

Chief Engineer

sigurjon.arason@matis.is

Increased value of pelagic species - FINAL REPORT / Increased value of pelagic species

The main objective of the project Increasing the value of pelagic fish - improved refrigeration technology, which began in June 2008, was to lay the foundations for a new method of cooling and storing pelagic fish on board seiners. The result of improved cooling is that a higher proportion of the catch is useful for human consumption. Partners in the project were Matís, Síldarvinnslan (SVN) and Skinney Þinganes (UN). This report describes the main results and products of the project. Examples of products are heat transfer models of pelagic catches in ships and storage tanks on land and the integration of heat transfer models and quality forecast models, which make it possible to predict the quality of raw materials based on environmental temperature history. Heat distribution in pelagic vessel loads with different versions of cooling systems was mapped and storage temperatures were linked to quality measurements made during landing. From temperature and quality measurements it is clear that the frequency of defects in landed catch increases with increasing storage temperature. The main advantage of the MCS (Mixed Cooling System) cooling system, which combines CSW (Chilled Sea Water) and RSW (Refrigerated Sea Water) cooling systems, is that the system can reduce the inevitable temperature rise that occurs in a pre-cooled vessel following the pumping of catch in lestina. During the project, the Icelandic mackerel fishery was the largest and it can be stated that the results of the project have been used very well to improve the results of food processing of mackerel in this country and thus increase the product prices of a valuable species.  

The main aim of the research project Increased value of pelagic species - improved chilling methods, which was initiated in June 2008, was to develop a new method for chilling and storing pelagic species on board purse seiners resulting in more valuable products. This report describes the main results and products of the project. Examples include heat transfer models of pelagic fish stored in a ship hold and a storage tank onshore and coupling of the heat transfer models and quality forecasting models, which makes it possible to predict spoilage of pelagic species as a function of ambient temperature history. Temperature distributions in ship holds with different cooling systems were mapped and storage temperature related to quality measurements conducted during landing. The fault ratio of landed raw material clearly increased, indicating lower quality, with higher storage temperature. The main advantage of a mixed cooling system (MCS), which combines RSW and CSW systems, compared to using only RSW is a lower temperature increase in a precooled ship hold caused by loading the catch in the hold. During the project, the emphasis on mackerel fishing increased significantly around Iceland. It can be stated that the results of this project have been widely exploited in order to improve the yield of the mackerel and thereby increase the profitability of that valuable species.

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Reports

CFD Modeling and Quality Forecasting for Cooling and Storage of Pelagic Species

Published:

01/04/2009

Authors:

Lárus Þorvaldsson, Björn Margeirsson, Sigurjón Arason

Supported by:

AVS Fisheries Research Fund, Byggðastofnun

Contact

Sigurjón Arason

Chief Engineer

sigurjon.arason@matis.is

CFD Modeling and Quality Forecasting for Cooling and Storage of Pelagic Species

In the project, a computerized thermal and hydrological model of storage tanks for pelagic catches is built. The input of the model is time-dependent ambient temperature, which in turn returns the temperature distribution of the mixture of pelagic catches and seawater stored in the tanks. That model is such an intertwined quality forecast model that indicates the development of damaging substances such as TMA and NH3 based on the temperature history obtained from the thermodynamics model. The main result of the project is the development and application of technology that makes it possible to predict the damage processes of pelagic catches at a given environmental temperature history. This technology could prove to be extremely useful in the handling and processing of pelagic catches. Collaborating companies in the project are Síldarvinnslan, Skinney‐ Þinganes and HB Grandi.

In this project a thermodynamic model of storage tanks used for cooling and storage of pelagic species is constructed. The input for the model is transient ambient temperature, which gives the temperature and velocity distribution in the mixture of pelagic species and seawater. This model is then coupled with a quality forecast model, which predicts the development of spoilage indicators such as TMA and NH3 from the temperature time series which are retrieved from the thermodynamic model. The main result of the project was the development and application of a technique which makes it possible to predict the spoilage of pelagic species given only ambient temperature history. This could prove immensely useful in the management and processing of pelagic species. The following companies take part in this project: Síldarvinnslan, Skinney ‐ Þinganes and HB Grandi.

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