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Technical Paper

Application of MC Method-Based H2 Fueling

To address challenges related to refueling with compressed hydrogen, a simple, analytical method has been developed that allows a hydrogen station to directly and accurately calculate an end-of-fill temperature in a hydrogen tank and thereby maximize the fill quantity and minimize the refueling time. This is referred to as the MC Fueling Method, where MC represents total heat capacity. The MC Method incorporates a set of thermodynamic parameters for the tank system that are used by the station in a simple analytical equation along with measured values of dispensed hydrogen temperature and pressure at the station. These parameters can be communicated to the hydrogen station either directly from the vehicle or from a database that is accessible by the station. Because the MC Method is based on direct measurements of actual thermodynamic conditions at the station, and quantified thermodynamic behavior of the tank system, highly accurate tank filling results can be achieved.
Technical Paper

Gaseous Hydrogen Station Test Apparatus: Verification of Hydrogen Dispenser Performance Utilizing Vehicle Representative Test Cylinders

The paper includes the development steps used in creating a station test apparatus (STA) and a description of the apparatus design. The purpose of this device is to simulate hydrogen vehicle conditions for the verification of gaseous hydrogen refueling station dispenser performance targets and hydrogen quality. This is done at the refueling station/vehicle interface (i.e. the refueling nozzle.) In addition, the device is to serve as a means for testing and developing future advanced fueling algorithms and protocols. The device is to be outfitted with vehicle representative container cylinders and sensors located inside and outside the apparatus to monitor refueling rate, ambient and internal gas temperature, pressure and weight of fuel transferred. Data is to be recorded during refueling and graphed automatically.
Technical Paper

Investigating the Optimum Practical Hydrogen Working Pressure for Gaseous Hydrogen Fueled Vehicles

Today's fuel cell powered vehicles typically utilize compressed hydrogen storage systems with a nominal working pressure of either 35MPa or 70Mpa. This coexistence of working pressures has, in a large part, developed in isolation, in that automakers have primarily considered vehicle side issues when choosing the storage system pressure. This study looks at hydrogen fueling from a holistic perspective by considering both vehicle side and station side issues with the goal to determine an optimum hydrogen working pressure. The approach utilized is to first conduct a data driven study of vehicle fueling at different working pressures and ambient temperatures to determine the vehicle and thermodynamic considerations of hydrogen fueling. This data is then contrasted with the hydrogen station hardware required to perform fueling at these temperatures and pressures.
Technical Paper

Thermodynamic Analysis of Fuel Processing

Thermodynamic analysis of equilibrium products and heat requirements is conducted for C8H18 (octane), CH4O (methanol), C2H6O (ethanol) and C3H8 (propane) at specified temperature and pressure. The equilibrium calculation utilizes the NASA equilibrium code by Gordon and MacBride. The temperature range is from 600 to 1700 K, and the pressure is set at 1 bar. The equilibrium calculation shows that the adiabatic temperatures are generally below 1300 K, except for C2H6O and C3H8 at their respective partial oxidation conditions considered in this paper. Calculation also shows that the presence of H2O in the reactant mixture yields high conversion of H2 at temperature above 1200 K, and above which the H2 mole fraction is relatively independent of the mixture temperature. Negligible C(graphite) is predicted for conditions with temperature above 1200 K.