Two flows
of air

State-of-the-art adsorption dehumidification
gives you full control

Brief intro to
Cotes technology

Cotes A/S in Denmark is the world’s leading expert in adsorption dehumidification technology, providing high-quality, low-maintenance humidity management solutions that are remarkably energy efficient.

A Cotes adsorption dehumidifier is a sleekly designed, fully enclosed unit that includes a rotor, geared motor, ventilator fan(s), heater, air filters and an integrated electrical control system.

We can also add other equipment and special heating/cooling capabilities to tackle your specific requirements. The best technology and the best know-how about how to apply it effectively are a potent combination.

For more information please contact us
T +45 5819 6322
[email protected]

How it works

A brief introduction to adsorption dehumidification.

Adsorption dehumidification

How it works

The effect of Cotes adsorption dehumidifiers basically stems from the action of two flows of air. The process is self-sustaining and requires little maintenance.

Process air — drying the air flow

  1. The incoming moisture-laden flow of air (process air) enters one side of the cabinet and gets filtered by a process air filter.
  2. The air then passes through a slowly turning rotor  whose inner surfaces are coated with desiccant silica crystals that attract the water molecules passing through. When the moist air passes through the rotor, water molecules are adsorbed and lodge in the pores on the surface of the silica gel.
  3. This means the air leaves the rotor containing less moisture (humidity) than when it entered. And because the adsorption process releases energy to the air, the temperature increases.
  4. The process air is controlled by a process air fan.

Regeneration air — drying the rotor with warmer air

  1. The second air flow (the regeneration air) is filtered by a regeneration air filter, and heated by heating elements.
  2. On its way through the rotor, this heat evaporates the moisture previously adsorbed by the silica crystals in the rotor.
  3. The resulting water vapour now leaves the dehumidifier in the outgoing regeneration air.
  4. The regeneration air is controlled by a regeneration air fan.


Rotor and silica gel

Moisture in the air flow – humidity – is captured in the slowly turning rotor. The rotor features a honeycomb structure made of fibreglass, with a very large surface area.

This surface is coated with silica gel. This is full of millions of tiny holes, which give the rotor an even larger surface area. 1 gram of silica gel has a hygroscopic surface area of approx. 800 square metres.

The rotors used in Cotes adsorption dehumidifiers normally have a hygroscopic surface area corresponding to the size of a football pitch. The silica gel is perfect for attracting water molecules, thus capturing the airborne moisture within the rotor.

Relative humidity
and the dew point

This film explains the relation between the relative humidity and dew point, and how you can manage this to get the results that suit you best.



+45 5819 6322
[email protected]

If you want to establish full control over humidity conditions in important structures, equipment and processes, Cotes are the people to get in touch with.

We’re experts on what happens when there’s moisture in the air – and how to apply advanced adsorption dehumidification technology to control and manage such humidity effectively.


+45 5819 6322
[email protected]