Hydrogen compression characteristics of a dual stage thermal compressor system utilizing LaNi5 and Ca0.6Mm0.4Ni5 as the working metal hydrides

The research performed herein consisted of the design, construction, and testing of a dual stage metal hydride hydrogen compression system intended to be used with lower grade geothermal or waste energy sources. The metal hydrides used in this study were LaNi5 and Ca(0.6)Mm(0.4)Ni(5). A Finite Time Thermodynamics (FTT) model was also developed and the model proved useful in determining how the compression results and energy requirements for the system change with variations in the system parameters. Dual stage system results showed a final compression ratio of approximately 12 when using cooling and heating temperatures of 10 degrees C and 90 degrees C, respectively. The final output pressures and compression ratios were found to follow an upward trend when increasing the heating bath temperatures. It can be concluded from the experimental results, that though the dual stage hydrogen compression system has room for improvement, it is an effective way of compressing the hydrogen from low initial pressures while using low grade energy sources. (C) 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.