An ejector refrigeration (ER) system using exhaust waste heat of a heavy vehicle engine is investigated. A program is developed using engineering equation solver software and it is used to make the calculations of the system. The system is taking all the efficiencies of system’s components into account. Refrigerants R134a and R245fa are used for the comparative simulation of the system. The pressure at the exit of the pump is varied from 6 to 14 MPa and 3 to 10 MPa for R134a and R245fa, respectively. It can be concluded that COP (coefficient of performance) of the system gradually increases with the increase in pump exit pressure. Results show that, the performance of the system would be higher if R245fa is preferred rather than R134a with the given operating conditions.