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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.

Interest in the hydrogen economy is growing rapidly on the world stage and the market for hydrogen fueling has the potential to become significant. Hydrogen storage onboard the vehicle is one of the challenges facing station and vehicle designers. The current leading candidate for onboard storage of hydrogen fuel is high pressure gaseous storage. At present, hydrogen is typically stored at a fueling system pressure of 35 MPa in high pressure storage tanks in the vehicles. There is currently some movement to go from 35 MPa to 70 MPa. Fueling of hydrogen vehicles must be accomplished in an acceptably safe and economically viable manner. This paper explores the benefits and costs of various pressure levels, 25 MPa, 35 MPa, 50 MPa and 70 MPa, and identifies which system pressure levels are most advantageous to station providers, OEMs, and ultimately to the consumers in both the development scenario, and the eventual mass production of vehicles.

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.