EKS-HUM-032 / Dehumidification technology and performance

Desiccant Regeneration

吸附剂再生

Desiccant regeneration is the process of releasing collected water from a desiccant so that its moisture-removal capacity is restored.

Aliases: desiccant reactivation, rotor reactivation

QUANTITY, SYMBOL AND UNIT

Quantity / objectDesiccant regeneration process

UnitNot applicable

Definition

Desiccant regeneration is the process of releasing collected water from a desiccant so that its moisture-removal capacity is restored.

In heat-regenerated atmospheric systems, heating raises the desiccant's water-vapour pressure and a regeneration airstream carries the released moisture away. Other dryer types can use different pressure, purge or cycle arrangements.

Relations and distinctions

Regeneration and dehumidification

Dehumidification loads the desiccant with water from process air; regeneration removes that water from the desiccant for reuse.

Regeneration and regeneration air

Regeneration is the desorption process; regeneration air is one stream used to supply heat and carry moisture away.

Engineering meaning

Include heater duty, airflow, exhaust path, seals, control range and heat recovery when reviewing regeneration.
Evaluate process performance and regeneration energy together because under-regeneration and excess heat both have consequences.

Common misconceptions

MisconceptionMore regeneration heat always produces proportionally more useful dehumidification.

Accurate explanationPerformance also depends on desiccant, air states, airflow, velocity, leakage and the equipment's operating limits.

Application boundaries

The applicable regeneration mechanism depends on whether the system uses a rotor, fixed bed or liquid desiccant.
A regeneration temperature without its measurement location and airflow does not define regeneration performance.

Supporting sources

ASHRAE / SRC-ASHRAE-S20-CH24

ASHRAE Handbook - HVAC Systems and Equipment, Chapter 24: Desiccant Dehumidification and Pressure-Drying Equipment ↗

2020 IP edition / Chapter 24, solid sorption and regeneration/reactivation sections
Supports: Regeneration reverses the water-removal mechanism and restores desiccant capacity; Heating can raise desiccant vapour pressure so moisture transfers to reactivation air; Regeneration conditions affect capacity and energy performance

Maintenance record