Energetic, Exergetic and Exergoeconomic Analysis of CO2 Refrigeration Systems Operating in Hot Climates

Carbon dioxide is one of the most interesting refrigerants in terms of both environmental impact and efficiency at low outdoor temperatures. Its use in warm climates still needs for some improvements as well as some economic evaluations in order to analyse its real potential in such weather conditions. CO2 refrigeration system with parallel compression represents one of the solutions which have been proposed in the last few years in order to enhance the performance of a single-stage refrigeration system. The main target of this study is to compare the thermodynamic efficiency and the final cost of the product of a R744 refrigeration solution with auxiliary compressor with those of a R744 conventional system, both of them operating in transcritical conditions. The results pointed out that the adoption of an auxiliary compressor resulted in an increase of the COP by approximately 18.7% over the investigated temperatures range. Furthermore, the final cost of the product associated with this solution was on average 6.7% lower than the one of the conventional solution.