Feasibility study of CO₂ accumulation

This report is deliverable number D 3.2.8 in the CREATIV project. In a time of fewer resources and rising energy prices savings in energy costs are an important goal for the food industry. This study analyses the potential of cold thermal energy storage applying an indirect carbon dioxide system to reduce the maximum level of power needed by the freezing plant and to minimize the part load operation of the main compressor unit.This study analyses the influence of cold thermal energy storage (CTES), using carbon dioxide as working fluid.Theoretical aspects are explained, a system concept is presented and industrial applications are discussed. Since fishing industry is a field of great interest, the example of a tunnel freezer, freezing 30t fish per day, is further explained. The tunnel freezer for pelagic fish is used as a base case for the modelling. A cascade process of ammonia and a carbon dioxide (CO₂) cycle is calculated for a 24 hours period.The calculation indicates that up to 30% less electricity is required for the equal freezing capacity, when CTES is applied.CTES is a promising technology. Using carbon dioxide for storage of cold energy offers a new temperature level for a wide range of applications. The proposed system offers a way to improve the performance of industrial applications as for example tunnel freezers. To design and operate a CTES system working with the natural working fluid CO₂ further research in freezing of CO₂ is required.