Application of silica gel fluidised bed for air-conditioning systems

• We theoretically/experimentally investigates a fluidised bed for dehumidification.
• Fluidised bed, compared with packed bed, increases adsorption/desorption by 20%.
• Fluidised bed, compared with packed bed, reduces pressure drop by 36%.
• Fluidised bed, compared with packed bed, reduces outlet temperature by 30%.
• Adsorption of fluidised bed increases with higher filling height and faster velocity.

This paper theoretically and experimentally investigates a periodic operating silica gel fluidised bed system to adsorb/desorb moisture in air-conditioning systems. First, the theoretical model of a fluidised bed system is utilised to predict the minimum fluidisation velocity, pressure drop, and adsorption/desorption performance of a silica gel fluidised bed. Subsequently, the paper experimentally compares the adsorption/desorption performance of the silica gel fluidised bed with a packed bed at the regeneration temperature of 40 °C, inlet temperature of 30 °C, inlet relative humidity of 60%, and wind velocity of 2 m/s periodically operating for 40 min. Then it applies two kinds of average diameter (3 mm and 5 mm) silica gel particles to the fluidised bed dehumidification system with various filling heights and differing wind velocities. The results show that the fluidised bed system, compared with the packed bed, increases the total amount of adsorption and desorption by 20.8% and 19.8%. It also reduces the pressure drop and outlet temperature by 30% and 36%. Moreover, the adsorption/desorption performance of fluidised bed systems increases with higher filling height and faster wind velocity. The availability of the theoretical modal is verified by 8% relative error between the theoretical and experimental values of the adsorption/desorption performance.