Enhancing CNG Cascade Refueling Efficiency for Heavy-Duty Transport Using Thermodynamic Management Techniques: Modeling and Optimization
Keywords:
CNG; Cascade Refueling; Heavy-Duty Transport; Thermodynamic Management; Fast-Fill; Energy EfficiencyAbstract
Compressed Natural Gas refueling for heavy-duty transport suffers from severe under-filling due to temperature rise during fast-fill, which elevates cylinder pressure and triggers premature dispenser cut-off. This study enhances cascade refueling efficiency through thermodynamic management and optimization of reservoir volume distribution. A thermodynamic model was developed for a three-bank cascade system supplying a 350 L heavy-duty cylinder rated at 200 bar. The model integrated real gas behavior with compressibility factor, mass and energy conservation principles, and convective heat transfer between gas and cylinder wall. Reservoir volume ratio was optimized, and a temperature-compensated target pressure strategy was introduced to account for heat-induced pressure elevation and prevent early termination. The coupled differential equations were solved numerically using fourth-order Runge-Kutta method with 0.1 second time step. Results demonstrated that the optimal volume distribution of 0.20:0.30:0.50 for Low, Medium and High banks achieved superior performance. Final charged mass increased from 36.8 kg to 42.5 kg, fill ratio improved from 82.3% to 96.2%, representing 13.9% enhancement and 15.5% mass increase. Peak gas temperature reduced from 67 to 55.2 degrees Celsius, refueling time decreased from 340 to 300 seconds, and energy consumption reduced by 18.5% from 8.20 to 6.68 megajoules. Residual gas decreased to 12.5 kg, yielding an additional 43 km driving range. The framework improves filling completeness, maintains safety below ISO 11439 limit, and offers practical design guidelines for CNG stations in hot climates like Nigeria.
References
Ali, Y., Younus, A., Khan, A. U., & Alrefai, A. H. (2024). Compressed natural gas (CNG) as a fuel and the associated risks: A quantitative analysis in the scenario of a developing country. Journal of Safety Science and Resilience, 5, 306–316. https://doi.org/10.1016/j.jnlssr.2024.04.001
Bhutani, S., Prabakaran, D., & Gupta, N. (2025). Electrification of light commercial vehicles in urban areas. Transportation Research Procedia, 82, 2425–2443. https://doi.org/10.1016/j.trpro.2025.02.150
Biswas, S., & Banerjee, R. (2023). In-cylinder pressure profiling for CNG/ethanol enriched biodiesel combustion. Fuel, 349, 127970. https://doi.org/10.1016/j.fuel.2023.127970
Carbone, C., Micari, S., & Lanzafame, R. (2025). An economic and environmental assessment of different bus powertrain technologies in public transportation. Cleaner Environmental Systems, 16, 100250. https://doi.org/10.1016/j.cesys.2025.100250
Evstifeev, A. A., & Zaeva, M. A. (2018). Analysis of compressor control structures and algorithms for compressor drives for automobile gas filling compressor stations. Procedia Computer Science, 136, 372–378. https://doi.org/10.1016/j.procs.2018.08.263
Farzaneh-Gord, M., & Deymi-Dashtebayaz, M. (2013). Optimizing natural gas fueling station reservoirs pressure based on ideal gas model. Polish Journal of Chemical Technology, 15(1), 88–96. https://doi.org/10.2478/pjct-2013-0014
Farzaneh-Gord, M., Eftekhari, H., Hashemi, S., Magrebi, M., & Dorafshan, M. (2007). The effect of initial conditions on filling process of CNG cylinders. Proceedings of the 2nd International Conference on Modeling, Simulation and Applied Optimization, Abu Dhabi, UAE.
Farzaneh-Gord, M., Saadat-Targhi, M., & Khadem, J. (2016). Selecting optimal volume ratio of reservoir tanks in CNG refueling station with multi-line storage system. International Journal of Hydrogen Energy, 41, 22438–22447. https://doi.org/10.1016/j.ijhydene.2016.08.178
Garud, K. S., & Lee, M. (2023). Grey relational based Taguchi analysis on heat transfer performances of direct oil spray cooling system for electric vehicle driving motor. International Journal of Heat and Mass Transfer, 201, 123596. https://doi.org/10.1016/j.ijheatmasstransfer.2022.123596
Khan, M. I., Yasmin, T., & Shakoor, A. (2015). Technical overview of compressed natural gas (CNG) as a transportation fuel. Renewable and Sustainable Energy Reviews, 51, 785–797. https://doi.org/10.1016/j.rser.2015.06.053
Kountz, K. J., & Blazek, C. F. (1997). NGV fueling station and dispenser control systems (Report GRI-97/0398). Gas Research Institute.
Kountz, K. J., Liss, W., & Blazek, C. F. (1998). A new natural gas dispenser control system. Proceedings of the 1998 International Gas Research Conference, San Diego, CA, USA.
Kountz, K. J., Liss, W., & Blazek, C. F. (1998). Method and apparatus for dispensing compressed natural gas. U.S. Patent No. 5,752,552.
Kountz, K. J., Liss, W., & Blazek, C. F. (1998). Automated process and system for dispensing compressed natural gas. U.S. Patent No. 5,810,058.
Liang, F.-Y., Ryvak, M., Sayeed, S., & Zhao, N. (2012). The role of natural gas as a primary fuel in the near future, including comparisons of acquisition, transmission and waste handling costs of NG with competitive alternatives. Chemistry Central Journal, 6(Suppl 1), S4. https://doi.org/10.1186/1752-153X-6-S1-S4
Liss, W. E., Richards, M. E., Kountz, K., & Kriha, K. (2003). Modeling and testing of fast-fill control algorithms for hydrogen fueling. Proceedings of the National Hydrogen Association Meeting.
Lv, Z., Wu, L., Yang, Z., Yang, L., Fang, T., & Mao, H. (2023). Comparison on real-world driving emission characteristics of CNG, LNG and hybrid-CNG buses. Energy, 263, 125571. https://doi.org/10.1016/j.energy.2022.125571
Martins, A. A., Silva, R. A., de Souza, A. F., & de Andrade, J. C. (2014). Cold start and full cycle emissions from a flexible fuel vehicle operating with natural gas, ethanol and gasoline. Journal of Natural Gas Science and Engineering, 17, 94–98. https://doi.org/10.1016/j.jngse.2014.01.013
Thomas, G., Goulding, J., & Munteam, C. (n.d.). Measurement, approval and verification of CNG dispensers (NWML KT11 Report). National Weights and Measures Laboratory.
Xu, Y., Wang, M., Chen, L., & Zhang, Y. (2024). Accident scenarios screening for integrated energy supply stations. International Journal of Hydrogen Energy, 51, 1038–1054. https://doi.org/10.1016/j.ijhydene.2023.11.086
