Study on Effective Thermal Conductivity of Hydrogen Absorbing Alloys Bed for Passive Type Hydrogen Absorption and Desorption Systems

Abstract

  This paper indicates the effective thermal conductivity of the hydrogen absorbing alloys bed of the passive type hydrogen storing systems for residential energy systems or stand-alone power supplies by experimental measurement.
  The effective thermal conductivity of the alloys bed depended on the cylinder pressure and the H/M composition of the alloys. Moreover, the conductivity was linear to the H/M composition at Plateau area.
  The introduction of 15 mass% Cu wires to the bed for improving the heat transfer was effective to raise the effective thermal conductivity of the bed. 50% of void fraction of the bed was also useful. The use of MmNi₅ resulted in raising the effective thermal conductivity compared to the use of MmNi_4.50Co_0.10Al_0.15Mn_0.25 at the same H/M composition and the void fraction.