The objective of this work is to investigate the parameters
affecting the time for complete solidification and fusion in
spherical capsules and develop correlations between this time
and the investigated parameters. These correlations will be used
in the numerical simulations of latent heat storage systems of
the fixed bed type having the phase change material, PCM
encapsulated in spherical containers. Four spherical shells of
35, 76, 106 and 131 mm diameter were used at temperatures
ranging from -20°C to -5°C for solidification process and
temperature of 10°C, 18°C, 25°C for the melting process.
Water and mixtures of water and polyethylene glycol in
percentages ranging from 7.5% to 50% were used as PCM.
Based on the experimental results correlations of the time for
complete solidification and complete fusion were developed
and compared with the experimental measurements showing
good agreement and confirming the suitability of using these
correlations to predict the complete phase change times. These
correlations are applicable in the ranges: 0.076 m Diameter of
spherical capsule 0.131m, 0.1% concentration of
polyethylene glycol 0.5%, -20°C Initial temperature of
PCM -5°C, 10°C Thermal bath temperature 25°C. The
differences between the values predicted by the correlation and
the experimental measurements are below 10%.
Papers presented to the 12th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Costa de Sol, Spain on 11-13 July 2016.