How a Dehumidifier Compressor Works

A dehumidifier compressor is the quiet motor that serves as the engine of a dehumidifier. The compressor is responsible for circulating the refrigerant through the dehumidifier, directing it toward the cooling coils. This triggers the actions of the condensing and evaporating coils in the appliance, which work to remove excess moisture from the air and expel drier air back into the environment.

Dehumidification Process

In order to understand how a dehumidifier compressor works, it is necessary to have a sense of the dehumidification process as a whole. In short, the circulating fan in a dehumidifier draws in humid air, and then passes it over cooling (or evaporating) coils where the water molecules in the air appear as condensation. This condensation is then released into the dehumidifier’s reservoir and disposed of manually or through a drain hose. The remaining air is then warmed and dried over the condensing (or heating) coils and expelled back into the room.

Refrigerant in the Evaporator Coil

A dehumidifier compressor is the heart of a refrigerant dehumidifier, which functions much like an air conditioning unit. The compressor pressurizes a refrigerant liquid like Freon, which works to heat the liquid. The compressor then pumps this through a tube where it is condensed and cooled slightly to room temperature, and then it is pumped over the evaporator coil, which makes the liquid quite cold. This manipulation of refrigeration prepares the coils for the dehumidification of the air.

Refrigerant in the Condenser Coil

The condenser coil (or heating coil) not only functions as a reheater for the air circulated by the internal fan – it also serves to turn the refrigerant back into liquid after a cycle of dehumidification. In other words, after the compressor rapidly heats the refrigerant, which is then cooled by the evaporator coil, the refrigerant then expands as a natural reaction to its compression. It then gives off heat, which helps warm the leftover air, and is returned to its liquid form. From there, the compression cycle begins again.

Relationship to Airflow

In essence, the heating and cooling of the refrigerant which triggered by the compressor, exists in an inverse relationship with the airflow. This airflow is cooled first in the dehumidifier, and then heated before being expelled back into the environment. This is because the refrigerant must be pressurized and then cooled significantly as a first step in the dehumidifying process, so that when the humid air is circulated through the appliance, it will immediately meet with the evaporator coils already cooled by the compressor. The meeting of warm air with the cold coil causes the necessary condensation.

As long as a dehumidifier is switched on, the dehumidifier compressor will repeat its pressurizing task over and over in a continuous cycle. This can be taxing on an appliance, particularly in a very humid area. In these situations, it is not uncommon for compressors to have a relatively short lifespan. Luckily, compressors typically carry short-term warranties for replacement.