Studies on La based intermetallic hydrides to determine their suitability in metal hydride based cooling systems

• Suitability of La based intermetallics in metal hydride cooling system was studied.
• Effect of composition change on transferable amount hydrogen was studied.
• Fine tuning of the La based intermetallics for MHCS was discussed.

The La0.9Ce0.1Ni5, La0.8Ce0.2Ni5, LaNi4.7Al0.3 and LaNi4.6Al0.4 intermetallic hydrides were characterised to determine their suitability in metal hydride based cooling system (MHCS). The performance of the MHCS depends on the driving potential, and rate and amount of hydrogen transfer between coupled metal hydride (MH) beds. Therefore, the effect of compositional changes on the variation of these parameters due to the variation in pressure – concentration isotherm (PCI) properties (storage capacity, plateau slope, hysteresis effect, etc.) of metal hydrides employed was studied. Compared to other possible MH pairs, La0.9Ce0.1Ni5 – LaNi4.7Al0.3 hydride pair exhibited high driving potential and transferrable amount of hydrogen, during cooling and regeneration processes, thereby better MHCS performance. In addition, the effect of change in hydrogen concentration (due to hydrogen transfer between coupled MH beds) on reaction enthalpy (ΔH) consequently on MHCS performance was found significant.