This master thesis is a part of a project initiated by the energy technology department at KTH. The project aims to provide useful insights on the Swedish cold chain for food and evaluate the potential of refrigeration systems using carbon dioxide in a food processing and storage facility. This thesis includes a detailed description of the main parts necessary to sustain a typical cold chain and an analysis of a facility that employs CO2 as its only refrigerant. The facility has the complete instrumentations necessary to measure temperatures, pressures, and the energy consumed by the
compressors and the fans in the storage rooms. The instruments have been installed at the beginning of 2018, but only the first semester of 2020 is thoroughly analyzed in this thesis. The measurements collected throughout this period were good enough for the evaluation of such a system. Because of the multi-functionality of the units, different performances were calculated, thus providing the tools for a meaningful and complete analysis. Particular attention was directed towards the overall COP and the heat recovery COP to better understand the improvements that the units can undergo. The potential to recover “free” heat from the desuperheater and the intercooler is demonstrated and discussed in the final chapters of this paper. The experimental and theoretical studies reported in this thesis prove that CO2 based systems can be employed as efficient solutions in food processing and storage facilities. However, comparison with other systems is needed and this work will be presented in publications that follow the ongoing project.
