Packed bed-pcm material latent heat thermal energy storage system

Abstract EN

Packed bed-PCM latent heat thermal energy storage system is presented in this study.

The packed bed cylindrical column is filled with spherical capsules of PCM (paraffin wax) that used for solar water heating application.

In this study, the physical model is developed to use for analyzing the thermal performance of packed bed-PCM latent heat thermal energy storage.

The model depends on energy balance equation that can be applicable only to the sensible heat storage materials and can be converted to enthalpy equation that can be applicable to the PCM storage bed.

The governing equations are numerically solved using simple explicit and first order finite difference technique.

The results obtained are used for the thermal behavior of both charging and discharging modes.

The effects of mass flow rate and inlet heat transfer fluid temperature (Stefan number) on the thermal performance of the PCM capsules of different radii are investigated.

The melt / solid fraction distribution of the bed as function of time and axial position during charging and discharging modes is investigated.

The results show that higher inlet heat fluid temperature and higher mass flow rate of heat transfer fluid indicates shorter time for complete charging processes.

The complete solidification time is too longer compared to the melting time.

This is due to the very low heat transfer coefficient during solidification.

The charging and discharging rate are significantly higher for the PCM capsule of smaller radius compared those of lager radius.

The phase transition temperature range reduces the complete melting time ; a difference of 31.7 % is observed for the case when the PCM has melting in the temperature range as compared to that for a PCM with at fixed temperature.