The existing FCEV have been developed with only a few vehicle models. With the diversification of both passenger and commercial FCEV lineups, as well as the increasing demand for vehicle trailer towing, there is a growing need for high-capacity fuel cell stacks to be applied in vehicles. However, at the current level, there are limitations and issues that arise, such as insufficient power output and reduced driving speed. As a results, the importance of thermal energy management has been increasing along with the increase in required power. Traditional cooling performance enhancement methods have mainly focused on developing increased hardware specifications, but even this approach has reached its limitation due to package, cost and weight problem. Therefore, it is essential to develop a new cooling system to solve the increases in heat dissipation. This study aims to develop an evaporative cooling system using water as a by-product of the stacks, and to identify the effects of variables, such as mass flow rate, spray angle, position and pressure, on its performance. The key factors of the system were analyzed in detail and locally, and STAR CCM+ was used to simulate to address the issue of high cost during evaluation. Additionally, quantitative sprayed areas were identified for cooling performance test. Based on the analysis results, empirical evaluation plan was carried out, and the performance of the cooling system was validated through the decreases in inlet temperature of the radiator. Through evaluation, it was possible to select the optimal nozzle specifications and positions. It was confirmed that the reduction in coolant inlet temperature could solve the issue of excessive heat dissipation. Additionally, by reducing the power consumption of the compressor in air conditioning system, it was possible to confirm the potential increases in driving range when applied to electric vehicle.