Entropy Production and Filling Time in Hydrogen Refueling Stations: An Economic Assessment.

Area of Science:

• Thermodynamics
• Chemical Engineering
• Sustainable Energy

Background:

• The standard protocol for hydrogen fueling, SAE J2601, is widely adopted but may not be optimal for efficiency.
• Hydrogen fueling stations aim to balance fast fill times with energy efficiency.

Purpose of the Study:

• To conduct a multi-objective optimization of hydrogen fueling conditions.
• To identify fueling parameters that improve filling times and thermodynamic efficiency (reduce entropy production).
• To compare optimized conditions against the SAE J2601 standard.

Main Methods:

• Multi-objective optimization was employed to analyze the trade-offs between filling time and total entropy production.
• The Pareto frontier was determined for these two process variables.
• Simulations were conducted across a range of ambient temperatures (10-40 °C).

Main Results:

• The study found that SAE J2601 is suboptimal for both filling time and entropy production.
• Reductions in filling time of 47-77% are achievable, with greater potential in hotter weather.
• Maximizing entropy savings (up to 7%) requires longer fill times (up to 350%) depending on ambient temperature.

Conclusions:

• Optimized fueling strategies can outperform SAE J2601, offering significant time and energy savings.
• Economic analysis in California suggests potential operating cost reductions of 8-28% without increasing fill times.
• Further research into optimized protocols can enhance the efficiency and cost-effectiveness of hydrogen refueling infrastructure.