The absorption kinetics of hydrogen into a LaNi 4.75 Al 0.25 /n-octane slurry was investigated in a stirred reactor. The rate-determining step was hydrogen absorption into the liquid n-octane phase in agreement with the model proposed by Reilly and Johnson (J. Less-Common Met. 1984, 104, 175). The activation energy was found to be approximately 8.4 kJ/mol of H 2 . Although the activation energies for hydrogen absorption into various slurry combinations are quite scattered, the data reported here indicate that the overall kinetics is sufficient for many practical applications.

An integral method is used to analyze the performance of a complete system model of a compressor-driven metal hydride heat pump. CFD studies incorporating the transient non-isothermal fully compressible nature of such systems have confirmed that high specific powers and COPs comparable to vapour compression cycles are achievable. Finite-time thermodynamic studies focusing on specific aspects of external heat exchanger design have identified the need for less computationally intensive models which include in a detailed manner all parasitic thermal losses as well the capability of capturing the thermal phase lags which occur between the reactors and the heat exchangers during steady-state operation. This paper develops a rigorous intermediate model which captures these effects. Parametric studies are presented as well as comparision with data from a prototype device.