A study of an alternative ejector cooling system is proposed in this paper. A mathematical model without irreversibility is developed and simulated. The numerical results are validated with literature data for two working fluids (R134a and R152a). The performance and behavior of the system using conventional refrigerants (HFC's, HC's) and unconventional (R717, R718) is obtained; the process uses 100 kW of heat available in a waste stream. Finally, the paper explores the reduction of problems associated with the use of conventional refrigerants by introducing the use of R718 (water) as the working fluid of the proposed system.