Parameters that Affect Electricity Consumption in Fish Freezing. Case Study

Reducing energy consumption in industry has become an important aspect on a global scale. Energy efficiency is one way of reducing energy consumption and promoting competitiveness. Increasing energy costs, security of energy supply, emissions from energy production have shown that current freezer design solutions are not sustainable. The food industry has a common tendency, whereby energy costs are only of secondary importance, unlike other production costs, resulting in minimal monitoring of energy consumption. Electricity consumption for freezer operation amounts to 20 % of total electricity consumption. Within the framework of this study, electricity consumption for fish freezing and storing frozen fish and finished products, as well as the coefficient of performance (COP) for compressors and parameters affecting COP were analyzed. From the results it can be concluded that the specific consumption of electricity in freezing of fish is lower than that of frozen fish storage. The two-stage compressor COP ranges from 2.4 to 3.7, but the single-stage compressor COP ranges from 3.7 to 5.5. The pressure in the condenser and ammonia vapor temperature after the compressor is affected by the temperature of the water used to cool the condenser and compressors. As the temperature of the water used for cooling increases, the condenser and ammonia vapor temperature after the compressor increase, which in turn reduces the compressor COP.