In response to increasingly stringent global emissions regulations, including Euro 7, the automotive industry is intensifying its focus on eco-friendly propulsion systems. Among them, hydrogen fuel cell electric vehicles (FCEVs) have emerged as a promising alternative in the commercial transport sector, offering high energy density, rapid refueling, long driving range, and minimal payload limitations. However, the operational efficiency and durability of fuel cell stacks heavily depend on effective thermal management, and insufficient cooling can lead to power degradation and reduced lifespan.
This study proposes a novel thermal management strategy that enhances stack cooling performance by directly applying fuel cell discharge water onto the radiator surface, utilizing latent heat of evaporation. To overcome the structural complexity and control challenges of high-pressure spray systems, a gravity-driven low-pressure drizzling method was adopted, achieving both system simplification and uniform water distribution.
Experimental testing was conducted using a vehicle-level cooling module, simulating real-world conditions by varying spray flow rate (1.4–2.8 LPM), spray distance (20–40 mm), radiator coolant flow (190–310 LPM), and fan speed (1200–1700 RPM). The results demonstrated a maximum thermal performance improvement of 24.61% in stack cooling.
Furthermore, a Random Forest-based predictive model was developed to quantify the influence of key variables and identify optimal operating conditions. The model predicted a performance improvement of 24.18% under the same conditions, with a minimal deviation of only 0.43 percentage points from the experimental results, confirming its high precision and reliability.
These findings indicate that the proposed predictive model can serve as a powerful tool for accurately forecasting system performance and determining optimal parameters when deploying drizzling-based evaporative cooling systems across various FCEV platforms. The study provides a practical and scalable approach to enhancing stack thermal management and accelerating the commercial deployment of hydrogen-powered commercial vehicles.