Abstract The Federal Institute of Metrology METAS developed a Hydrogen Field Test Standard (HFTS) that can be used for field verification and calibration of hydrogen refuelling stations. The testing method is based on the gravimetric principle. The experimental design of the HFTS as well as the description of the method are presented here. The HFTS has been tested at METAS with nitrogen gas at −40 °C to mimic a refuelling process in the field. Laboratory tests have shown that icing on the pipes of the HFTS have a non-negligible impact on the results. Field-testing with the HFTS has also been performed at the Empa hydrogen refuelling station with hydrogen at up to 70 MPa. The major uncertainty components have been identified and assigned values. The required expanded uncertainty of 0.3% could be achieved. A detailed uncertainty budget has been presented and shows that the scale is the largest contributor; buoyancy corrections only play a minor role. For the lowest uncertainty measurements, appropriate waiting times or cleaning methods to get rid of icing are required.

中文翻译：

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加氢站现场测试重力一级标准设计

摘要 联邦计量研究所 METAS 制定了氢气现场测试标准 (HFTS)，可用于加氢站的现场验证和校准。测试方法基于重量原理。这里介绍了 HFTS 的实验设计以及该方法的描述。HFTS 已在 METAS 使用 -40 °C 的氮气进行测试，以模拟现场加油过程。实验室测试表明，HFTS 管道上的结冰对结果的影响不可忽视。Empa 加氢站也使用 HFTS 进行了现场测试，氢气压力高达 70 MPa。主要的不确定性成分已经确定并指定了值。可以实现所需的 0.3% 的扩展不确定度。已提供详细的不确定性预算，表明规模是最大的贡献者；浮力修正只起次要作用。对于最低不确定性测量，需要适当的等待时间或清洁方法以去除结冰。