Overview
ASTM D7265-23 defines the standard specification for hydrogen thermophysical property tables, providing critical data for calculating pressure-volume-temperature (PVT), thermodynamic, and transport properties of normal hydrogen. These extensive tables, developed by the National Institute of Standards and Technology (NIST) based on their REFPROP software database, cover gaseous hydrogen at temperatures from 50 K to 500 K and pressures up to 500 MPa. The standard is intended for use in process design and operations, with a strong focus on hydrogen fuel cell applications.
Key Topics
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Hydrogen Thermophysical Data: The standard offers detailed values for key properties, including:
- Molar density
- Molar volume
- Molar enthalpy
- Molar entropy
- Constant volume molar heat capacity (Cv)
- Constant pressure molar heat capacity (Cp)
- Speed of sound
- Viscosity
- Thermal conductivity
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Reference States: The property tables use standard reference states for enthalpy and entropy at 298.15 K and 0.101325 MPa, ensuring consistency and accuracy in calculations.
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Comprehensive Coverage: Tables are provided for a wide range of pressures and temperatures, including newly added tables for 35 MPa (350 bar) and 70 MPa (700 bar) - typical hydrogen fuel cell vehicle pressures.
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Intended Use: While the data is strictly for pure gaseous hydrogen, the tables can be valuable in developing mathematical models for hydrogen-containing mixtures.
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Standardized Approach: The document adheres to internationally recognized principles of standardization in line with World Trade Organization (WTO) guidelines on technical barriers to trade.
Applications
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Hydrogen Fuel Cell Systems: Essential for the design and operational analysis of hydrogen storage and dispensing systems in fuel cell vehicles and stationary applications.
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Process Design in Industry: Provides a reliable foundation for engineering calculations involving hydrogen, such as pipeline transport, storage facilities, and energy systems.
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Research and Development: Enables consistent thermodynamic and transport property data for simulation and modeling in academic and industrial research settings.
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Safety and Compliance: Facilitates adherence to safety standards by providing accurate hydrogen property data for risk assessment and engineering controls.
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Software Integration: The property tables are compatible with engineering software applications, particularly those utilizing the NIST REFPROP database, supporting automated calculations and system optimization.
Related Standards
To support and complement the use of ASTM D7265-23, consider the following related standards:
- ASTM D4150: Terminology Relating to Gaseous Fuels
- REFPROP (NIST Reference Fluid Thermodynamic and Transport Properties Database): The foundational data source for creating the property tables in D7265-23
- Additional hydrogen-related standards issued by ASTM Committee D03 on Gaseous Fuels
Practical Value
Engineers, researchers, and designers in the hydrogen energy sector rely on accurate, standardized data to achieve efficient, safe, and innovative solutions. ASTM D7265-23 fulfills this need by providing trusted property tables that underpin wide-ranging hydrogen applications, particularly in the rapidly growing sector of hydrogen fuel cell technology.
Keywords: ASTM D7265-23, hydrogen thermophysical properties, hydrogen property tables, hydrogen fuel cells, hydrogen gas data, thermodynamic properties of hydrogen, transport properties, NIST REFPROP, hydrogen process design.