Standardized equation for hydrogen gas compressibility factor for fuel consumption applications

The hydrogen gas compressibility factor is a key parameter when the pressure-temperature method is used to measure hydrogen fuel consumption. Based on the data from the National Institute of Standards and Technology (NIST) Chemistry WebBooks, a standardized equation for hydrogen gas compressibility factor based on pressure and temperature dependent terms is developed by means of polynomial fitting. The equation agrees with the NIST density data to within 0.01% from 220 K to 500 K with pressures from 0.1 MPa to 100 MPa, and to within 0.003% from 270 K to 500 K with pressures from 10 MPa to 100 MPa, which has higher accuracy compared with the Lemmon equation. Experimental research shows that the hydrogen consumptions calculated by using the proposed equation are in good consistency with the results measured by the flowmeter. The proposed equation can be easily used in the calculation of hydrogen fuel consumption.