This project aims to show the reader the latest trends in refrigeration and argue how important it is to promote the use of natural refrigerants for a more sustainable future. From there, the work will focus on the use of CO2 as a refrigerant in commercial systems, as well as on the technological innovations applied to such systems. As the main part of the study, the operation and technical specifications of the project Supersmart-Rack will be explained, conducted in the laboratory NTNU/SINTEF, and in which the writer of this report has been collaborating for six months. This project, which involves a CO2 cooling system with parallel compression and multiejectors, aims to take profit of the experimental unit to make a step forward in the creation of standard units that will reduce the cost of such systems. In addition to its general operation, part of the set-up of the unit elaborated by the writer will be described below, as well as the resulting environmental and economic analysis of the project and, finally, the conclusions. The annexes include documentation related to the project and elaborated by the writer, some necessary calculations and drawings of the experimental unit.