🔍 Key Concepts

• Adsorption vs absorption in air dryers and what happens when desiccant (silica gel) is saturated • How twin-tower desiccant dryers alternate between an "on-service" (drying) tower and an "off-service" (regenerating) tower • Typical regeneration methods for silica gel desiccant: use of heat and/or purge air rather than cooling

💭 Think About

• Think about whether you want to keep moist air flowing through the same tower while you are trying to dry (rejuvenate) its silica gel, or whether you should first switch towers. • Consider what heat does to saturated silica gel and whether it is normally applied to the tower that is handling the main air stream or to the tower that has been taken out of service. • Ask yourself if refrigeration would drive off moisture from silica gel or if a different temperature change is usually used to regenerate desiccant.

✅ Before You Answer

• Verify whether desiccant regeneration typically happens while the tower is in service or out of service for the main air flow. • Check whether silica gel gives up its absorbed/adsorbed water more effectively when heated or when cooled. • Confirm that in a twin-tower system, the normal sequence is to shift towers first, then apply the regeneration method to the one that was just taken offline.