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Hydrogen Field Test Standard: Laboratory Performance

Published

Author(s)

Jodie G. Pope, John D. Wright

Abstract

NIST developed a prototype field test standard (FTS) that incorporates three test methods that could be used by state weights and measures inspectors to periodically test retail hydrogen dispensers, much as gasoline dispensers are tested today. The three field test methods are: 1) gravimetric, 2) Pressure, Volume, Temperature (PVT), and 3) master meter. The FTS was tested in NIST’s Transient Flow Facility with helium gas. All three methods agree within the expected uncertainty of 0.57 % for all collections of helium gas in the laboratory setting. The time required to perform six test drafts is similar for all three methods, ranging from 5.8 h for the gravimetric method to 7.5 h for the PVT method. The estimated cost of equipment to perform each method ranges from $18K (PVT method) to $29K (master meter method). The laboratory tests show that 1) it is critical to wait for thermal equilibrium to achieve density measurements in the FTS that meet the uncertainty requirements for the PVT and master meter methods and 2) buoyancy corrections are important for the lowest uncertainty gravimetric measurements. The wait time for thermal equilibrium following a fill or blow-down of the FTS tank will depend on the temperature difference between the atmosphere and the gas collected in the FTS. In general, we found a wait time of 20 min introduces errors
Conference Dates
April 14-17, 2015
Conference Location
Washington DC, DC
Conference Title
9th International Symposium on Fluid Flow Measurement

Keywords

hydrogen dispenser, field test
Created April 14, 2014, Updated February 19, 2017