Wind turbine and wind farm dehumidification

High relative humidity is a major contributor to corrosion of metal parts within both the tower and the nacelle of a wind turbine. At relative humidity levels above 55% up to 95% there can be a 6 fold increase in the corrosion rate of metal parts. Offshore installations have the added problem of a salt laden atmosphere, which significantly increases the rate of corrosion.

High internal relative humidity within the wind turbine increases the likelihood of condensation from the natural cycle of daytime warming and night-time cooling. Even small reductions in temperature can cause condensation on internal surfaces. If the daytime internal condition is 20°C and 75%RH, the temperature only has to reduce by 4.5°C to reach a point at which condensation forms.

However if the relative humidity is reduced to 40% there has to be a 14°C reduction to form condensation.

Condensation can damage electronic components, leading to downtime on the generator and higher associated maintenance cost. In winter it can lead to ice formation internally to the turbine. Long term condensation can lead to a reduction in the expected operational life of a turbine of 20+ years.

Towers and nacelles are not airtight, small openings can allow comparatively large air ingress bringing in considerable moisture loads. The rate of ingress will be increased by the wind pressure on the structure. With a medium wind speed of around 30mph, a 1cm opening will allow about 5m³ of air per hour to enter the structure. Multiplied by the potential number of openings across the whole structure a total airchange of between 0.25 and 0.5 per hour would not be uncommon. In humid environments this can result in a moisture addition of approximately 2-3kg/hr.

  • Around the 45-50%RH. However, it could be lower if there is a larget temperature range between day and night conditions.

  • Desiccant dehumidifier systems offer the best solution for wind turbines, as they are very flexible in operation. They offer a wide range of operational temperatures, typically -30 to +40°C, together with ambient humidity from 0-100%RH.

    The overall drying capacity needed in a wind turbine may not be that large in terms of moisture removal, consequently even on large towers small compact desiccant dehumidifiers can be employed.

  • Whilst heating will certainly reduce the relative humidity level it does not reduce the absolute humidity. Absolute humidity is the mass of water per unit volume of air (quantity of moisture in the air). Neither does it reduce the dewpoint temperature, so if the surface temperature reduces, condensation will still form.

    Heating will not be a successful humidity control strategy.

Benefits of Condair dehumidification in wind turbines

  • Avoid higher maintenance costs and turbine downtime.
  • Maximise the operational lifetime of the turbine.
  • Extensive experience in projects around the world.
  • Comprehensive product range with specialised units for offshore environments
  • Local engineering support for reliable operation in critical environments

Bunkermuseum Hanstholm

Erik Ansø

Museumsforvalter

“Støjniveauet er nu så lavt at man kan tale normalt sammen i ventilationsrummet selvom både ventilationen og en affugter kører, hvilket jo var et af kriterierne. Det kunne man bestemt ikke tidligere, og det er altså godt gået i en betonbunker”

Prime Ocean

Jan Bork Nordmann

Produktion

““Affugtningsløsningen fra Condair er en af de bedste investeringer, som vi har lavet hernede.”
- Jan Bork Nordmann - Produktion, Prime Ocean

Prime Ocean er en af Europas største importører af fersk torsk fra FAO27 og importerer samtidig store volumener af laks hovedsageligt fra Norge og Færøerne. Der produceres både ferske fiskeprodukter og frosne produkter af høj kvalitet.
Affugtningsløsningen har hjulpet med at fjerne kondensproblemer, de daglige driftstop på maskinerne så godt som elimineret og arbejdet med vedligehold af både maskiner og bygninger er væsentligt minimeret.”

Vyra Suites Hotel in Qatar

Kiran Nair

Sales Engineer at Mentor Trading

“The ceiling mounted dehumidifiers are compact in size and were fixed above the pool and spa areas. We were very satisfied with Condair’s service and their prompt response to the project.

The quality of the Condair DP-C dehumidifiers is of a high standard and they were easy to install and simple for the customer to operate. We look forward to a working with the Condair team in the future.”

T Clarke

Doug Lumb

Project Engineer

“The Condair DC 50W dehumidifier was actually chosen by our designers, as it fitted the bill perfectly for the environment. The unit size was based on the quantities of kit hung in the room to dry when the firefighters return to the Centre at the end of their training exercises.

It’s a reliable product and currently operating at the station just as expected, plus installation was really simple and didn’t take long at all, so all very good.

I would definitely specify Condair dehumidifiers for future projects.”

The Savanna

Lisa Gardshol

Founder and CEO

“We have been very happy with the performance of the Condair dehumidifiers JTR installed to comply with our drying approach. It has not only allowed us to increase production efficiency but also produce our award-winning biltong.

We have full control over the entire process and can make decisions based on the data that we recieve. This is something which we couldn’t do as well before.”

John Todd Refrigeration (JTR)

Matt Gough

Refrigeration Engineer

“The rooms need very tight environmental control but the previous strategy introduced outside air to help lower temperatures when needed. JTR redesigned the drying rooms and installed Condair DC-N dehumidifiers.

The dehumidifiers, located in the rooms, both dry and heat the air to the required condition, resulting in a fully sealed area and a consistently controlled drying process.”

Talk to an expert in wind turbine dehumidification

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Learn the important things to consider when approaching a commercial dehumidifier project.

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