Cotes dehumidifiers enable you to control
humidity inside wind turbines

Combating moisture
and salts

Airborne moisture is one of the biggest sources of operating disruption, damage to equipment and structures, and costly practical problems inside the nacelles and towers of wind turbines — especially those offshore.

Such airborne moisture combines with acidic salts in the air to cause corrosion, as well as giving rise to condensation and bacterial growth. Together, these result in a big range of different problems with structures, coatings, mechanicals and electronics, as well as causing electrical glitches and expensive unscheduled downtime.

Related products
Cotes Wind
Cotes Overpressure System

Two approaches

Specialised Cotes Wind dehumidifiers — and the patented Cotes Overpressure System — provide the easiest and most effective way to limit the combined effects of moisture and salts inside wind turbines, by automatically managing the levels of humidity present.


Cotes Overpressure System
A complete, patented dehumidification system designed to help prevent the ingress of moist, salt-laden air into wind turbine nacelles and towers. The Cotes Overpressure System helps you prevent humidity problems from even arising.

Cotes Overpressure System


Cotes Wind
Conventional stand-alone dehumidifiers specially designed and configured for installation inside wind turbine nacelles and towers. Cotes Wind dehumidifiers help you deal with humidity once it is present.

Cotes Wind Dehumidifiers

Cotes Wind
Overpressure System

This patented dehumidification set-up creates a dry, salt-free environment inside nacelles and towers, reducing downtime, rolling back service costs and extending service life — providing better ROI on offshore wind turbine installations.

As the name implies, the system works by helping ensure that the air pressure inside wind turbines is greater than the surrounding air, thus preventing moist, salt-laden air from entering through the many openings.

This special Cotes dehumidifier set-up mixes the wet, salty air entering the structure with a flow of dry air. This makes the moisture evaporate, and the salt crystallises, making it easy to filter out. The drier, de-salted air can then be used to help protect delicate electronics and other equipment.

Combining the Cotes Overpressure System with an add-on heat exchanger unit also provides a straightforward, reliable way to keep the air around sensitive equipment under temperature-controlled conditions.

Download the brochure
Dealing wit corrosion and salt in offshore wind turbines

Learn more
Cotes Overpressure System

CWO - How it works

A visual explanation of Cotes Wind Overpressure system.

Cotes Wind dehumidifiers

These compact, lightweight dehumidifiers are specially configured for installation inside the nacelles and towers of wind turbines. Their small size and limited weight make it easy to mount these units within even small spaces.

They are also remarkably reliable, providing operators with full control of humidity conditions in order to maximise uptime and revenue. The dehumidifier is automatically turned on and off in order to maintain any designated relative humidity set point, as required to meet the desired conditions.

The general design is based on the fact that any salt present in air will crystallise if the relative humidity is low enough, and that such crystals can then be captured in appropriate types of filter.

The special design of these units prevents the air filters from becoming blocked by wet, salt-laden air. The filter cassette, which has a particularly large filter area, has an exceptionally long service life

The special design of these units features a filter cassette with a particularly large filter area to prevent blockages, and ensure long service life.

Download the brochure
Cotes Wind brochure

Read more
Cotes Wind product page


The Cotes Overpressure System has been nominated as one of 5 major Danish technical innovations for Danish Industry’s 2014 Product Prize.


More on this

Combating corrosion

Cotes adsorption dehumidifiers enable you to control the levels of humidity and salt inside wind turbines, and the patented Cotes overpressure solution can help you keep moist, salt-laden air from getting in.

Getting control of corrosion means you can work with lower ISO 9223 classification requirements — which means lower costs for wind turbine materials, coatings and components.

Helps with cooling, too
Attached to heat exchangers or cooling coils, the Cotes overpressure system can also be included to boost the effectiveness of the cooling set-up inside wind turbines.

Download the booklet
Managing humidity in Offshore Wind Turbines


Prevention is better than repair

Cotes dehumidifiers also help you keep nacelles and towers — and the expensive fixtures inside them — in ready-for-service condition while in storage and en route to the erection site. This gives you big savings on commissioning as well as rolling back maintenance and service costs — and keeps up the revenue stream.


Dehumidification is a vastly more effective way to deal with moisture problems than old-fashioned, energy-burning heating units. Furthermore, all Cotes adsorption dehumidifiers are designed to be exceptionally energy-efficient, with energy consumption as much as 60% less than any other comparable systems. This makes these compact, reliable units particularly easy to install in wind turbines, whether onshore or offshore.


Relative humidity
and the dewpoint

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

who to contact

Nailing the dehumidification set-up best suited for your company’s exact set-up usually takes more than a simple off-the-shelf purchase.

Talk to one of the Cotes dehumidification experts about how you can get the best possible results from a Cotes Overpressure System.

Nailing the dehumidification set-up best suited for your company’s exact set-up usually takes more than a simple off-the-shelf purchase.

Talk to one of the Cotes dehumidification experts about how you can get the best possible results from a Cotes Overpressure System.