Prediction of metal-hydride refrigerator performance based on reactor heat and mass transfer

The performance of a metal-hydride refrigerator working with a ZrMnFe MmNi4.5Al0.5 pair is predicted by solving the coupled heat- and mass-transfer equations of the two reactors. Effects of bed parameters such as bed thickness and effective thermal conductivity, and operating parameters such as heat-source temperature and refrigeration temperature are studied. Results show that the specific output, and hence the cost of the system, depend significantly on these parameters. Of the four processes which constitute the cycle, desorption at the low-temperature reactor is the slowest. For a given bed thickness, there is an optimum effective thermal conductivity above which its effect on cycle time and specific output is negligible. This optimum value increases with increasing bed thickness, thereby emphasizing the advantages of thin beds. © 1995.