Design optimization plays a pivotal role in enhancing the performance of accumulators, especially focusing on spatial distribution of temperature, pressure, density and entropy at the Top Dead Center position. Understanding this behavior allows to design and operate system more effectively, leading to improved performance, longevity, and reliability of the entire system. This study investigates how optimizing accumulator design influences energy storage and release dynamics, crucial for improving overall system efficiency and help in identifying potential points of failure or areas that might reinforcement. This research aims to develop a CFD model and conduct an analytical investigation into the pressurization process of gas from a vessel utilized in a system (accumulator) for wind turbine or hybrid vehicles. The study focuses on nitrogen and helium as the working fluids. The pressurization procedure is approached many problems in mass and heat transfer, analyzed using the First Law of Thermodynamics for stream within a control region. Transient flow analysis is utilized in the CFD model to simulate this process. The research specifically examines vessels pressurized to certain level, considering both nitrogen and helium in the analytical solutions. Comparisons are made between results obtained from analytical methods, MATLAB and CFD simulations to validate the CFD model’s accuracy. The results show significant agreement in gas temperature and pressure variations, affirming the reliability of the CFD model. Analysis of gas dynamics highlights nitrogen’s pressure and temperature distributions, contrasting with helium’s higher pressure and broader temperature fluctuations, which underscore their distinct molecular properties and thermal behaviors.