In this study, a 3D Eulerian-Lagrangian algorithm is employed to evaluate the Nitrotherm electrostatic spray technique, with the goal of optimizing transfer efficiency and enhancing painting performance. The fluid dynamics are simulated by solving the unsteady 3D compressible Navier-Stokes equations, while particle motion is modeled by tracking the distribution of droplet sizes. Implemented within the OpenFOAM framework, the algorithm incorporates a Large Eddy Simulation (LES) turbulence model to capture the high Reynolds number airflow. Additionally, it includes detailed simulations of spray dynamics, electric fields, and droplet trajectories. The findings suggest that using heated nitrogen-enriched air, instead of compressed air, reduces paint consumption and improves transfer efficiency (TE). The Nitrotherm technique also decreases application time by leveraging the low temperature of pure nitrogen for quicker curing, evaporation, and drying, resulting in a higher-quality paint film. This approach contributes to producing a superior cosmetic paint finish on the target and minimizes overspray, leading to a notably thicker film compared to conventional methods using compressed air.