Cotes Wind Overpressure CWO35
CWO35
Wind Overpressure dehumidifier for offshore wind turbines
The CWO35 is part of the Cotes Wind Overpressure (CWO) product family — adsorption-based climate control systems developed specifically for offshore wind turbines and offshore energy infrastructure.
The unit operates using the Cotes Wind Overpressure principle, combining controlled overpressure, filtration, adsorption drying and desalting.
Unlike conventional dehumidification systems that continuously attempt to dry incoming air, the CWO concept focuses first on limiting how much humid and salt-laden marine air can enter the structure.
By maintaining a controlled internal overpressure, the CWO35 reduces the amount of external air entering the turbine tower. This means the system primarily stabilises and improves the internal air column, rather than continuously drying new incoming air.
As a result, the drying demand is reduced while humidity levels and salt contamination inside the structure are stabilised.
At the same time, the system continuously dries and desalts the internal air, reducing corrosion risk and improving the reliability of electrical and structural components.
Explanation of Naming
The product designation follows Cotes naming logic:
- C – Cotes adsorption-based climate solution platform
- W – Wind industry application
- O – Overpressure operating principle
- 35 – Capacity class within the CWO product family
The CWO designation identifies systems designed to combine pressure control, filtration, adsorption drying and desalting.
Position within the Cotes Wind Overpressure family
The CWO35 represents the mid-capacity system within the Wind Overpressure range.
The CWO family consists of:
- CWO26 – compact offshore tower climate control system
- CWO35 – mid-capacity offshore tower system
- CWO65 – higher-capacity system for larger tower volumes and higher air exchange environments
All units apply the same Cotes Wind Overpressure strategy, combining:
- controlled internal overpressure
- filtration of incoming air
- adsorption drying
- desalting of the internal air column
Unlike onshore retrofit solutions such as the Cotes Mobile Wind family, CWO systems are typically integrated into offshore turbine or offshore infrastructure design.
TECHNICAL DATA
PATENTED OVERPRESSURE PRINCIPLE
Maintains controlled internal pressure to reduce uncontrolled ingress of humid and salt-laden marine air.
APPLICATION KNOW-HOW
Developed specifically for wind turbines operating in offshore environments exposed to humidity, salt aerosol and pressure fluctuations.
ADSORPTION DRYING PRINCIPLE
Rotor-based adsorption technology removes moisture from the internal air column and helps prevent condensation.
DESALTING FUNCTION
By filtering incoming air and continuously drying the internal air column, the system progressively reduces salt contamination inside the structure.
Frequently Asked Questions
For our full FAQ section you can go to www.cotes.com/FAQ
On this page we highlight some of the more frequently asked questions from customers.
Traditional dehumidification systems must continuously treat incoming humid air. In offshore environments this results in a large and constant drying load.
The Wind Overpressure strategy instead limits how much external air enters the structure. By maintaining a slight internal overpressure, the ingress of humid and salt-laden air is reduced.
Because less external air enters the tower, the system primarily stabilises and dries the internal air column rather than continuously treating new air.
Salt particles enter turbines through ventilation, pressure differences and service access. Combined with humidity, salt accelerates corrosion and electrical failures.
The CWO system progressively removes salt from the internal air column while limiting additional salt ingress.
CWO systems were originally developed for offshore wind turbines, where humidity and salt exposure are constant and environmental conditions are particularly aggressive.
However, similar conditions can also occur in coastal or nearshore onshore turbines, where waves and strong coastal winds inject salt aerosol into the air. In these environments, salt-laden humidity can enter the turbine through ventilation openings, service access and pressure differences.
In such cases, the desalting and humidity stabilisation capabilities of the CWO concept can also be relevant.
For inland onshore turbines without significant salt exposure, other solutions such as Cotes Mobile Wind systems are typically sufficient.