Experimental Sorption Dynamic in Packed Bed of Silica Gel

The Design and Test for Degradation of Energy Density of a Silica Gel-Based Energy Storage System Using Low Grade Heat for Desorption Phase

“…adsorbent. This difference increases with time, and reaches about 5 g per kg of adsorbent at the end of the 165 min duration, and it is expected to gradually increase for longer periods [19]. Results shown in Figure 4 illustrate the maximum amount of water vapor that can be adsorbed by the silica gel in the given time of operation.…”

“…They showed that the curve bends as the adsorption approaches saturation. Furthermore, results from Amorim et al [19] showed that for 650 g of silica gel with particle diameter of 4 mm, inlet temperature of 26 • C, flow speed of 0.5 m/s and relative humidity of 70%, the phase amount of water adsorbed approaches 0 kg of water vapor/kg of silica gel after 20 h. However, there was about 27% more water adsorbed in 2 h and 45 min for this work than was reported by Amorim et al, and this may be due to higher flow velocity used (1.4 m/s). Therefore, it is expected to see the leveling of the curve sooner than 20 h.…”

“…Works from Jahnig and Ng et al [14,27] show that silica gel is usually regenerated with temperatures between 90 to 160 • C over a period of 5 h. The difference in the mass adsorbed between the first and fifth cycles in the first 20 min during adsorption is about 3 g of water vapor per kg of adsorbent. This difference increases with time, and reaches about 5 g per kg of adsorbent at the end of the 165 min duration, and it is expected to gradually increase for longer periods [19]. adsorbent.…”

“…Thus, saturation is not reached for all cycles. Several researches on silica gel have shown adsorption of moisture for over 7 h duration [19,26]. Hence, it will require an additional 4 h for saturation to be reached in this work.…”

“…The efficiency of the proposed system is highly dependent on the operating parameters to enable the determination of the measuring cycle repeatability and degradation [18,19]. Specific air flow rates are selected to allow effective heat adsorption and delivery from the selected storage material.…”