Large amounts of CO2 are release to the environment due to classical cooling systems, namely the ones that are electrically driven. Also the use harmful refrigerants in conventional refrigeration systems contribute to the green effect and the ozone depletion potential. In this way research has been carried out in order to find out new cooling systems free of those problems. This work points out the sustainability of the refrigeration systems as well as reviews the classical systems for cooling as well as the new ones that emerged from recent research.