ABSTRACT
Storage of energy in the packed beds is experimentally investigated. Experiments
are carried out to measure the time dependent temperature distributions inside two
vertically oriented packed beds constructed from PVC cylinders with 0.15 and 0.25 m
inside diameters, respectively. Rock grains of two irregular sizes ranging between 15 to
20 mm and between 30 to 35 mm, respectively, are packed inside the beds at different
aspect ratios ranging from 1.0 to 4.5. For each bed, temperatures at different axial and
radial positions as well as the axial pressure distribution are measured at different
operating parameters. The stored energy, exergy and the bed efficiencies based on both
the 1st and the 2nd laws of thermodynamics are calculated utilizing the present
measurements.
The influence of bed diameter, bed aspect ratio, packing grains size, air flow rate,
and the inlet air temperature on the system storage characteristics are investigated. The
present results for the stored energy, exergy per unit storage volume, system efficiencies
and the charging duration are correlated as functions of the different operating and
design parameters. |
