Energy and exergy analyses are carried out for an air-cooled vapor compression chilled water (VCCW) using an alternative working fluid R1234ze to R134a. A thermodynamic model is developed using the Engineering Equation Solver (EES). A parametric study is conducted to investigate the effect of evaporating and ambient temperatures on the energy and exergy efficiencies, the total exergy destruction and the exergy losses in different components of the system. For both refrigerants, no important differences are observed between the energy and the exergy efficiencies. Among the components, the compressor presents the highest exergy destruction, followed by the condenser, the expansion valve and the evaporator. The irreversibility obtained in the unit using R1234ze is lower than the R134a. R1234ze is a good alternative to R134a in the VCCW systems. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.