Silica gel is packed between aluminum fins in individual fin-tube heat exchangers. The silica gel is only exposed to gaseous refrigerant (water) vapor. It never contacts liquid water. The hot water and cooling water flow through tubes in the heat exchanger to heat and cool the heat exchanger, which then heats and cools the silica gel. The hot water never directly contacts the silica gel.
The silica gel operates in a vacuum between 30 and 95 C. It does not disintegrate or become damaged in any way, and it does not move. Each heat exchanger is less than 30 mm tall so the bed height of silica gel is less than 30 mm. Therefore, there is almost no weight on each individual silica gel bed.
No changeout is ever required over the life of the machine.
Each adsorbent chamber has multiple, individual heat exchangers with their own bed of silica gel.
In this application, the silica gel operates between 5% and 15% loading by weight of water vapor. That varies based on operating temperatures. The gel never becomes saturated with water vapor.
The silica gel operates in a closed system in a vacuum inside the chiller. It never comes into contact with contaminants such as oils that could foul the surface. It never contacts the hot water or cooling water in any way. The silica gel does not lose performance over time, as verified in the field by hundreds of installations since the 1980’s.