Wind energy

High flying

Wind farms are expanding around the world. This is good for climate change. Wind turbines are being installed on the high seas with nacelle heights of more than 100 meters and rotor diameters of nearly 170 meters. This increases both the electricity yield and economic efficiency. Freudenberg is aiding wind power’s conquest with high performance components and materials.

The name has a military overtone, but it is the future of wind power: In the middle of the Baltic Sea between Germany, Denmark and Sweden, the “Kriegers Flak” wind farm is rising from the sea to over an area of 132 square kilometers. At dizzying heights of more than 100 meters, massive towers bear nacelles and 80-meter blades, giving the wind turbines a total height of almost 200 meters - by comparison the Cologne Cathedral is only 157 meters high. The latest generation of turbines to be built in Kriegers Flak are among the most powerful in the world; each individual turbine can generate up to eight megawatts of electricity. And with good reason. The more powerful turbines require smaller foundations, fewer towers and fewer cables relative to the energy yield – and can thus be run more efficiently. More and more turbines can now operate without any government support. Wind power is thus being established as an independent, climate friendly energy form.

Freudenberg is aiding wind power’s conquest with high performance components and materials.

Seals must withstand high winds

Multi-megawatt wind farms on the high seas bring more than higher yields. Even though the power generated by each turbine increases with the blade surface, the harvested winds place greater strain on components such as the primary bearings or the rotor blades. The same applies to seals that Freudenberg Sealing Technologies develops for wind turbines. The seals help keep sand or salty water from penetrating machine elements through important interfaces such as where yaw bearings between the tower and nacelle meet, the rotor blade bearings as well as the primary bearings. They also help make sure that lubricants remain securely in the interior. Increased winds make this all much more difficult. Freudenberg Sealing Technologies has thus developed a special Seventomatic seal for extremely large shaft diameters. Instead of the old radial springs, Seventomatic seals use a meander spring, which makes the seal less susceptible to big movements and dislocation of the main bearing. The greater flexibility enables better compensation exceeding several millimeters and prevents unwanted leaks.

Seals must withstand high winds

Multi-megawatt wind farms on the high seas bring more than higher yields. Even though the power generated by each turbine increases with the blade surface, the harvested winds place greater strain on components such as the primary bearings or the rotor blades. The same applies to seals that Freudenberg Sealing Technologies develops for wind turbines. The seals help keep sand or salty water from penetrating machine elements through important interfaces such as where yaw bearings between the tower and nacelle meet, the rotor blade bearings as well as the primary bearings. They also help make sure that lubricants remain securely in the interior. Increased winds make this all much more difficult.

Freudenberg Sealing Technologies has thus developed a special Seventomatic seal for extremely large shaft diameters. Instead of the old radial springs, Seventomatic seals use a meander spring, which makes the seal less susceptible to big movements and dislocation of the main bearing. The greater flexibility enables better compensation exceeding several millimeters and prevents unwanted leaks.

Three different specialty lubricants reduce friction

Wind turbines have an entire series of friction points where the use of specialty lubricants can help eliminate or alleviate wear and tear. The lubricants increase the wind turbine’s efficiency and component operating life - helping improve operating efficiency. Also, the less lubricant used, the lower the logistic expenses needed to organize lubricant replenishment, making maintenance more efficient, which can be very costly in offshore farms on the high seas.

Special oils are normally used in transmissions, while the lubrication points such as the main bearings, the rotary bearings and bearings in the generator use grease. The yaw gear drives used to shift the rotary blades and the nacelle to track the wind also need to be efficiently lubricated. Klüber Lubrication has developed a family of three special lubricants and precisely tailored them to the various applications and made them suitable for all the lubrication points in a wind turbine. The lubricants are also biodegradable - whenever necessary for the application. The uppermost goal is always to significantly improve the efficiency of electricity generation.

ChemTrend manufactures mold release agents needed in the manufacture of rotor blades - a very complex, extremely sophisticated manufacturing process. The blades are “baked” in forms and the mold release agent helps remove the component from the tool safely and without any damage to the surface. OKS supplies biodegradable cleaning agents, used to clean turbine blades during operations. SurTec manufactures chemical surface treatment products, such as those used to protect against corrosion and attachment elements, which can help guarantee a long life for the components.

Nonwovens with super-absorbent powder protect underwater cables

All the components in a wind turbine are designed to have rotation movement driven by the wind transformed into electrical current and transported to the end customer with as little loss as possible. At sea, special submarine cables are used to transmit electricity. Technical nonwovens from Freudenberg help protect these cables. Even though the submarine cables are placed in a trench dug for them on the seabed, they can still be damaged by sharp edges on the sea floor. The submarine cable cannot always be protected from anchors and other mechanical forces. Should there be any damage, a super-absorbent polymer powder in the Freudenberg nonwoven material causes it to swell, blocking off the complex hollow space in the submarine cable and quickly preventing water penetration. The nonwoven material thus plays an important role in limiting damage. Consequently, power companies replace much shorter lengths of defective cable which reduces the risk and cost. In addition to the swelling, other properties such as excellent conductivity and very high tensile strength are vital to making the Freudenberg Performance Materials nonwovens a functional part of the cable. This example also illustrates: Freudenberg solutions in many places help wind turbines around the world generate more environmentally friendly electricity and operate more efficiently than ever before.


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