EKS-HUM-029 / Dehumidification technology and performance

Refrigerant Dehumidification

制冷式除湿

Refrigerant dehumidification uses a refrigeration cycle to cool air below its dew point, condense water on an evaporator and drain the condensate.

Aliases: refrigeration dehumidification, condensing dehumidification

QUANTITY, SYMBOL AND UNIT

Quantity / objectRefrigerant dehumidification process

UnitNot applicable

Definition

Refrigerant dehumidification uses a refrigeration cycle to cool air below its dew point, condense water on an evaporator and drain the condensate.

The cooled air is commonly reheated with recovered condenser heat before it returns to the space or process. Moisture removal depends strongly on entering temperature and humidity, airflow, coil condition and refrigeration control.

Relations and distinctions

Refrigerant and desiccant dehumidification

Refrigerant equipment removes water by cooling and condensation; desiccant equipment transfers vapour to a sorbent that must be regenerated.

Dehumidification and sensible cooling

Air must reach a coil condition below its dew point for condensation. Sensible cooling above dew point lowers temperature without removing water.

Engineering meaning

Compare capacity at the actual entering-air state, not only at a catalogue rating point.
Check condensate drainage, heat rejection, reheat needs, low-temperature operation and defrost behaviour.

Common misconceptions

MisconceptionA fixed refrigerant dehumidifier removes the same amount of water at every room condition.

Accurate explanationMoisture removal falls as entering dew point and temperature change, and frosting or controls can further change time-averaged performance.

Application boundaries

The technology name does not specify refrigerant, compressor arrangement, heat-rejection method or control sequence.
Very low dew-point duties may require a different or staged process after operating conditions are reviewed.

Supporting sources

ASHRAE / SRC-ASHRAE-S20-CH25

ASHRAE Handbook - HVAC Systems and Equipment, Chapter 25: Mechanical Dehumidifiers and Related Components ↗

2020 SI edition / Chapter 25, operating principles, especially moisture removal below dew point and reheat
Supports: Mechanical dehumidification cools air below its dew point so water condenses; A refrigeration circuit can recover heat to reheat leaving air; Low entering temperatures can create frosting and require operating controls

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