METHOD OF MANUFACTURING A PANEL OF A WIND TURBINE NACELLE
1. A method of manufacturing a panel of a wind turbine nacelle, which method comprises the steps ofproviding a mold for the panel;
- arranging at least one divider in the mold to spatially divide the mold into at least a first mold region and a second mold region;
arranging composite material in the mold;
curing the composite material; and
separating the cured panel into at least a first panel portion and a second panel portion along a line defined by a divider.
Provided is a method of manufacturing a panel of a wind turbine nacelle, which method includes the steps of providing a mold for the panel; arranging at least one divider in the mold to spatially divide the mold into at least a first mold region and a second mold region; arranging composite material in the mold; curing the composite material; and separating the cured panel into at least a first panel portion and a second panel portion along a line defined by a divider. Also provided is a method of constructing a wind turbine nacelle, and a wind turbine including such a nacelle.
- 1. A method of manufacturing a panel of a wind turbine nacelle, which method comprises the steps of
providing a mold for the panel; arranging at least one divider in the mold to spatially divide the mold into at least a first mold region and a second mold region; arranging composite material in the mold; curing the composite material; and separating the cured panel into at least a first panel portion and a second panel portion along a line defined by a divider.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
This application claims priority to ES Application No. P201800245, having a filing date of Oct. 29, 2018, the entire contents of which are hereby incorporated by reference.
The following describes a method of manufacturing a panel of a wind turbine nacelle; a method of constructing a wind turbine nacelle; and a wind turbine.
The shipping container most commonly used for transport in Europe and China has the ISO 668 1AA designation, i.e. a length of 40′, a width of 8′, and a height of 8′6″. Such a container is usually simply referred to as a “40-foot standard container”. This container size can be used to transport a variety of different payloads. However, any object whose length exceeds 40′ (12.19 m) cannot be transported using such a shipping container.
For a large wind turbine with a generator comprising a gearbox, the enclosing nacelle may need to have a length in excess of 40′, so that transport of nacelle parts to the installation site may pose significant logistical problems that are costly to resolve. One approach is to manufacture the nacelle using only panels that comply with the 40′ constraint, and to assemble the panels on site. For a long nacelle in excess of 40′, each panel section is molded using a dedicated mold, which adds significantly to the overall manufacturing costs.
An aspect relates to an alternative way of constructing a nacelle from parts that can be transported using a standard shipping container.
According to embodiments of the invention, the method of manufacturing a panel of a wind turbine nacelle comprises the steps of providing a mold for the panel; arranging at least one divider in the mold to spatially divide the mold interior into at least a first mold region and a second mold region; arranging composite material of the mold; curing the composite material; and separating the panel into at least a first panel portion and a second panel portion along a line defined by a divider. The panel can later be assembled from the panel portions.
It shall be understood that the shape and dimensions of the mold correspond to the shape and dimensions of a complete panel, i.e. the mold is a negative of the complete panel. Such a panel may be assumed to comprise a number of sides or faces, for example a panel may comprise part of the nacelle floor and also part of a nacelle side wall. It shall be assumed that the panel dimensions exceed the size constraints of a 40-foot shipping container. One or more dividers are arranged in the mold so that the dimensions of each resulting mold region (and corresponding panel portion) lie within payload size constraints of a 40-foot shipping container.
A single divider can be used to define two panel portions for any panel that can be constructed from two portions, each of which fits into a 40-foot shipping container. Of course, any number of dividers can be used to obtain three or more panel portions of a multi-part panel. Since a divider is arranged in the mold to spatially divide the mold interior into adjacent mold regions, it may be assumed to protrude into the mold interior, i.e. to occupy space which would otherwise (in the absence of the divider) be filled by composite material.
Since a divider is used to divide the mold into regions, i.e. to divide a panel into portions, it may be referred to in the following as a mold divider, a panel divider, or a panel separator. The step of arranging composite material in the mold may be understood as the usual layup technique in which layers of composite material such as fiber glass mats, carbon-fiber reinforced plastic, rovings etc., are arranged in the mold. Generally, this is preceded by applying a release agent to all mold surfaces and also to all relevant surfaces of a panel divider. It is also usual to apply a suitable gelcoat layer that will form the outer surface of the cured part. After curing, the panel is demolded, and the divider is removed from between the adjacent panel portions.
An advantage of the inventive method is that it is not necessary to design individual smaller panels that fit into a 40-foot shipping container, and it is not necessary to provide dedicated molds for such panels. Instead, it is possible to use the mold of a large panel (i.e. any panel whose length exceeds the length of a 40-foot shipping container) as a basis, from which smaller panel portions are formed by judicious placement of one or more dividers in the mold. Costs can be kept to a favorable minimum by using an already existing mold for such a large panel, for example a mold used to manufacture a 13 m side, floor or roof panel of a nacelle.
According to embodiments of the invention, the method of constructing a wind turbine nacelle comprises the steps of providing a set of nacelle panels at an installation site, whereby at least one panel is a multi-part panel manufactured using the inventive panel manufacturing method as described above; connecting panel portions of a multi-part panel; and assembling all panels of the set to obtain the complete nacelle. Since the panel portions of any panel of the nacelle can be manufactured with relatively little effort to fit inside a 40-foot shipping container, the nacelle manufacturing and transport costs can be kept to an advantageously low level.
According to embodiments of the invention, the wind turbine comprises a nacelle constructed in the manner described above. The costs associated with construction of the nacelle can be reduced as described above, so that the cost of installing the wind turbine is also correspondingly low.
Particularly advantageous embodiments and features of the invention are given by the dependent claims, as revealed in the following description. Features of different claim categories may be combined as appropriate to give further embodiments not described herein.
A 40-foot shipping container is sometimes also referred to as a “maritime container” or “standard container”, so that these terms may be used interchangeably.
In the following, without restricting embodiments of the invention in any way, it may be assumed that the nacelle is for a wind turbine comprising a drivetrain with a gearbox, power converter modules etc., since this type of wind turbine requires a relatively long nacelle to accommodate the various components.
After curing the panel, it is separated into two or more panel portions. As explained above, a divider occupies space which would otherwise be filled by composite material. In a very simple approach, a divider can comprise a band of suitable material such as metal, plastic etc. that is at least as thick as the composite material, i.e. at least as thick as the panel wall thickness. In such an approach, composite material can be laid up in the mold on either side of the divider. After curing, the panel portions can simply be lifted out of the mold. However, such an approach may involve more effort in the lay-up process, since the edges of each portion must terminate cleanly along the divider. Therefore, in preferred embodiments of the invention, the composite material is arranged in the mold to completely cover the divider. After curing, adjacent panel portions are separated by cutting along a line defined by the corresponding divider.
Adjacent panel portions must be joined together when the nacelle is being assembled. A joint between adjacent panel portions must be structurally strong as well as water-tight. Therefore, the divider is not simply used to delineate adjacent panel portions, and is instead shaped to also define a connection interface between the panel portions. In preferred embodiments of the invention, a divider comprises a T-shaped profile, for example a T-bar having dimensions of a standard EN-10055 profile, or two back-to-back standard EN-10056 angle profiles. While these standards apply to steel parts, the divider used in the inventive method can be made of any suitable material and is shaped according to such a standard. With one or more such T-shaped dividers arranged in the mold, the resulting cast panel will exhibit one or more corresponding raised ridges. The individual panel portions can be separated easily by cutting through the raised ridge formed by a divider. The height of the cutting line can be chosen to leave a flange along the edge of each panel portion, and the corresponding flanges can be connected together in a suitable manner when the nacelle is being assembled.
A nacelle panel does not always comprise a simple flat or planar shape. Instead, a nacelle panel (and its corresponding mold) may include a step or other contour. Therefore, in preferred embodiments of the invention, a panel divider is shaped to follow such a step or a contour in the mold.
During layup, it is necessary to ensure that the divider does not move from its original position, so that the panel portions will have the intended dimensions. Therefore, in preferred embodiments of the invention, the step of providing the mold comprises a step of forming inserts to receive fasteners for securing a panel divider to a surface of the mold. A row of holes can be formed in the mold, for example along a line corresponding to the center line of a divider, so that the divider can be screwed to the mold (using screws inserted from the outside of the mold).
Once the panel portions of a nacelle have been manufactured as described above, these can be loaded into a standard container and transported to an installation site.
The panels of a nacelle are generally manufactured to a high degree of accuracy, so that when the panels are assembled, the nacelle specifications are met. Using the inventive method, panel portions of a panel are manufactured using a mold whose dimensions correspond to the complete panel. However, because one or more dividers are used to define the panel portions, the combined length of the panel portions will be less than the specified length of a panel. The difference will correspond essentially to the total width of the dividers used in manufacturing the panel portions. Therefore, in preferred embodiments of the invention, the step of connecting adjacent panel portions comprises arranging a spacer between the panel portions, wherein the thickness of the spacer corresponds to the thickness of the divider that was used to delineate those panel portions. Such a spacer can be an injection-molded or 3D-printed part, for example a 3D-printed part made from a suitable thermoplastic such as acrylonitrile styrene acrylate (ASA). Such a spacer comprises a spacer body and a sealant layer such as a strip of sealing tape applied to the spacer body and arranged to lie against a corresponding surface of a panel portion. The thickness of a spacer does not exceed the thickness of the corresponding divider. The spacer body exhibits a high degree of stiffness.
As mentioned above, two adjacent panel portions can have a low flange along their edges, and these can be joined together when the nacelle is being assembled. Such a joint or “seam” can be relatively long. Therefore, instead of providing a single spacer with the same length as the joint or seam, a spacer comprises a plurality of shorter spacer elements. In preferred embodiments of the invention, the spacer elements are formed so that each spacer element is shaped to engage with an adjacent spacer element. A connection between adjacent spacer elements can be achieved by a suitable form-fit shape of the corresponding edges of adjacent spacer elements. Such an approach allows a favorably quick assembly of adjacent panel portions.
To ensure a robust connection between panel portions, these are bolted or screwed together. To this end, a spacer comprises a number of bushings, wherein a bushing is arranged to accommodate a fastener used to connect two panel portions. The spacer can be formed so that the outer end of a bushing extends beyond the level of the spacer body by an amount corresponding to the thickness of a sealant layer.
A spacer and/or spacer elements can be made of any suitable material and can be made using any suitable technique. For example, spacer elements can be made as injection-molded parts. Equally, spacer elements can be 3D-printed parts made from a suitable thermoplastic such as acrylonitrile styrene acrylate (ASA).
Some of the embodiments will be described in detail, with reference to the following figures, wherein like designations denote like members, wherein:
In the manufacturing method according to embodiments of the invention, a different approach is taken. Here, a mold 3 which been constructed for the manufacture of a one-piece panel 1 as shown in
Although the present invention has been disclosed in the form of preferred embodiments and variations thereon, it will be understood that numerous additional modifications and variations could be made thereto without departing from the scope of the invention. For example, a divider can be bolted onto the mold by fasteners extending through the body of the divider and into the body of the mold. Alternatively, a divider can be secured to the mold using any suitable adhesive. Instead of the spacer described above, two panel portions can be joined or connected using any suitable parts, whereby the dimensions of the parts and the materials from which they are made may be chosen under consideration of factors such as material hardness, compressibility, durability etc.
For the sake of clarity, it is to be understood that the use of “a” or “an” throughout this application does not exclude a plurality, and “comprising” does not exclude other steps or elements.