The desiccant should also be strong. It should be able to withstand system vibrations and surges. The beads of desiccant often brush against each other they are violently shaken or vibrated, breaking down to granular particles.
Zeolite is choice for an ideal desiccant. It is s activated alumina, silica gel, calcium chloride, and calcium oxide. They are available in nature as well as can be manufactured artificially. They are able to soak, and hold moisture through capillary action.
HVAC technicians often recommend adding alcohol-based additives in refrigeration systems. This is because alcohol does not let moisture to freeze and thereby affect the metering device. However, adding alcoholic additives is not recommended. As modern desiccants, such as zeolite are prone to absorb these additives to an even greater degree than moisture. They will release certain amount of moisture into the system that they had absorbed to soak in these additives.