Heat Transfer Enhancement by Forming Bridges among Reactive Particles in a Packed Bed Reactor of a Solid-gas Chemical Heat Storage System

In this study, the enhancement of the thermal output of solid-gas chemical heat storage systems was investigated. Bridges made of high-thermal conductivity materials were formed among reactive particles by drying a slurry which contained graphite powder as a thermal additive and dispersant in a packed-bed reactor. First, the effect of the volume ratio of the dispersant on effective thermal conductivity was investigated. The optimum volume ratio of dispersant to graphite powder was determined. Furthermore, repetitive bridge formation increased the effective thermal conductivity. Based on these results, we investigated the thermal response of the energy-discharge process. Consequently, the temperature distribution in the radial direction of the reactor decreased owing to the formation of bridges. In addition, the thermal energy generated by the adsorption of water vapor onto the adsorbent was effectively transferred to the reactor wall. The thermal output was estimated based on the experimental results. The thermal output was increased by the formation of bridges.