The main purpose of this study is to develop a liquid desiccant and dew point evaporative cooling-assisted 100% outdoor air system (LDEOS), and to evaluate its energy saving potentials. In recent years, non-vapor-compression air conditioning systems are becoming available without compromising energy efficiency, thermal comfort, and ventilation requirements. A quasi-dynamic simulation model of LDEOS including a dew point evaporative cooler model was developed to compare the energy performance of LDEOS against a typical variable air volume (VAV) system. A sequence of operation for LDEOS was also proposed. Simulation results showed that LDEOS could save 12% of primary energy compared to a conventional VAV, while 100% of outdoor air was conditioned and delivered to the space without using vapor compression technology.