This document discusses icing and icing mitigation systems for wind turbines. It begins with an introduction about wind turbines and the issues of icing in cold climates. Then it describes how icing forms and the different types of icing including in-cloud, precipitation and frost. The effects of icing such as reduced aerodynamics and power losses are also outlined. The document concludes by explaining both passive and active systems for anti-icing and de-icing turbines, such as special coatings, heating elements, and warm air methods.

1. ICING AND ICING MITIGATION OF
WIND TURBINE
PRESENTED BY: GUIDED BY:
ABOOBACKER MT NISAR O
CEANEME003 ASSISTANT PROFESSOR
S8 ME1 MECHANICAL DEPT.
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2. CONTENTS
• Introduction
• Icing of wind turbine
• Ice formation
• Type of icing
• Effect of icing
• Icing mitigation system
• Conclusion
• References
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3. INTRODUCTION
• Wind energy, mainly applied for electricity generation
using wind turbine
• There are two important issues related to wind turbine
performance in offshore site
• That located in cold region and presence of
atmospheric icing
• Atmospheric icing due to water condensed in
atmosphere
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4. ICING OF WIND TURBINE
• The phenomena of icing means climates exposed to
freezing temperature
• As the wind energy project continue to be developed
in these region
• Surface of wind turbine blade are inevitably exposed
to icing
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5. 5

6. ICING FORMATION DEPENDS ON
• Air temperature
• Relative humidity
• Wind speed
• Air density
• Altitude
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7. TYPE OF ICING
1. In-cloud icing
2. Precipitation
3. Frost
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8. 1.IN-CLOUD ICING
• It happens when super cooled water droplets hit a
surface below 0 °C and freeze upon impact.
• The droplets temperature can be as low as −30 °C and
they do not freeze in the air, because of their size.
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9. TYPE OF IN-CLOUD ICING
• Soft rime
• Hard rime
• Glaze
• Wet snow
• Freezing rain
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10. RIME ICE GLAZE ICE
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11. 2. PRECIPITATION
• It can be snow or rain.
• The accretion rate can be much higher than in-cloud,
which causes more damage.
3. FROST
• It also called hoarfrost
• It forms when the temperature of the surface is lower
than the dew point of the air.
• This causes water vapour to deposit on the surface
forming small ice crystals
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12. EFFECT OF ICING
• Aerodynamic effects
• Mass imbalance
• Power losses
• Safety risk
• Effects on instrumentation and controls.
• Measurement errors
• Mechanical failures
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13. AERODYNAMIC EFFECT
• The build-up of ice on the wind turbine blades
disturbs the aerodynamics which decreases the power
production
• For severe icing, it may not be possible to start the
turbine with subsequent loss of all possible power
production.
• Even for slight icing, the roughness due to ice
adhesion may also alter the aerodynamics and
therefore leads to power loss.
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14. MASS IMBALANCE
• The added ice mass increases the loads on all turbine
components.
• Asymmetric masses cause a mass imbalance between
blades, which might reduce the turbine lifetime
significantly.
• Blade mass imbalance induces rotor mass imbalance
and leads to vibrations of rotating shaft
• Resonance may occur due to change of natural
frequencies of the blades.
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15. POWER LOSSES
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16. ICING MITIGATION SYSTEM
• Icing mitigation system have two process
1. ANTI-ICING: To prevent ice to accrete on object
2. DE-ICING: It is the process of removing the ice
layer from the surface
• The both strategies can divided into two method:
passive and active
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17. PASSIVE ANTI-ICING SYSTEM
1. SPECIAL COATING:
• Ice-phobic coatings prevent ice from sticking to the
surface because of their anti-adherent property.
• While super-hydrophobic coatings do not allow water
to remain on the surface because of repulsive features
2. BLACK PAINT:
• Black paint allows blade heating during daylight and
is used with an ice-phobic coating.
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18. 3.CHEMICALS:
• When applied on blade surface, chemicals lower the
water's freezing.
DISADVANTAGES:
• It is a pollutant
• It needs special maintenance.
• It cannot remain on the surface of the blade for a long
period.
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19. PASSIVE DE-ICING SYSTEM
1. FLEXIBLE BLADES:
• Flexible blades are flexible enough to crack the ice
loose.
• Blade flexing is known to help shed the ice.
2. ACTIVE PITCHING:
• Semi-active methods use start/stop cycles to
orient iced blades into the sun.
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20. ACTIVE ANTI-ICING SYSTEM
1. THERMAL:
• Heating resistance and warm air can be used in anti-
icing mode to prevent icing..
ADVANTAGES:
• No ice accumulates on blades.
• Blade can be kept at−5 °C, instead of 0 °C, in good
condition.
DISADVANTAGES:
• It needs a lot of energy
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21. 2. AIR LAYER
• Air layer consist in an air flow
• It originating inside the blade
• The air is pushed through rows of small holes near
the blades
• To prevent the ice formation
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22. 3. MICROWAVE
• It consists of heating the blade's material with
microwaves to prevent ice formation.
• The objective is to maintain the blade surface
at a temperature slightly above 0 °C, it save
some energy
• It is recommended to cover the surface of the
blade with a material that reflects microwaves
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23. ACTIVE DE-ICING SYSTEM
1. HEATING RESISTANCE:
• It consists of electrical heating element embedded
inside the membrane or laminated on the surface.
• The idea is to create a water film between the ice and
the surface.
• Electrically heated foils can be heating wires or
carbon fibres.Heating elements cover the leading
edge area of the blade.
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24. 2. WARM AIR AND RADIATOR:
• It consists of blowing warm air into the rotor blade
at standstill with special tubes.
• Blowers located in the root of each blade or inside the
hub produce the hot air.
• The heat is transferred through the blade shell in
order to keep the blade free of ice.
DISADVANTAGES:
• This method consumes lot of power
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25. CONCLUSION
• Icing of wind turbines is by no means trivial.
• It is necessary to understand how icing occurs, and
the effects of icing.
• There are two reasons.
• One is based on the model for icing and other is that
the blade tips can experience icing due to low clouds.
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26. REFERENCES
• 1) Jasinski, W.J., Noe, S.C., Selig, M.S. and Bragg,
M.B, “Wind Turbine Performance under Icing
Conditions, Aerospace Sciences Meeting & Exhibit”.
AIAA, 1997, pp. 8.
• 2) Makkonen, L. and Autti, M, “The Effects of Icing
on Wind Turbines”, EWEC, 1991, pp. 575-580
• 3) Battisti, L., Baggio, P. and Fedrizzi, R, “Warm-Air
Intermittent De-Icing System for Wind Turbines”,
Wind Engineering, 2006, pp. 361-374
• 4) Tammelin, B, “Wind Energy Production in Cold
Climate” (WECO),2000
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27. THANK YOU
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