The Second Law (Exergy) Analysis of Hydrogen

As the carrier of the accepted future clean energy, hydrogen is endowed by many energy missions. If the hydrogen economy is realized, the hydrogen will certainly be the mina fuel, so it is very important to analyze the hydrogen explosion capacity, i.e. the fuel exergy of hydrogen. Based on the systematical analysis of fuel exergy, the fuel exergy of hydrogen is analyzed and discussed in this article, combining with the physical properties and the utilization trends. Through the comparison of the fuel exergy of hydrogen and other ideal gases, if the hydrogen is used for power generation, it will be scientific utilization only when the efficiency of the second law of thermodynamics exceeds 6.7 (the efficiency of natural gas) in the energy utilization, which will challenge the reasonable utilization of hydrogen. The result of analysis and computation indicates that the fuel exergy of hydrogen exceeded the lower heat value (LHV), and was less than the higher heat value (HHV).