A NACELLE FOR A WIND TURBINE

Abstract

The invention relates to a wind turbine nacelle (2, 40) configured for mounting on a wind turbine tower (3), the nacelle comprising a top cover comprising multiple cover elements (41, 42, 43, 44), of which at least one is a dome cover element (44) comprising a dome-shaped part (45); wherein said nacelle has a second configuration in which said dome-shaped part (45) protrudes upwards and a first configuration in which said dome-shaped part (45) protrudes downwards.

Claims

1. A wind turbine nacelle configured for mounting on a wind turbine tower, the nacelle comprising; a top cover comprising multiple cover elements, of which at least one is a dome cover element comprising a dome-shaped part; wherein said nacelle has a first configuration in which said dome-shaped part protrudes downwards and a second configuration in which said dome-shaped part protrudes upwards.

2. The nacelle according to claim 1, wherein said first configuration is a transportation configuration with a first height of said wind turbine nacelle, and said second configuration is an assembled configuration with a second height of said wind turbine nacelle, the second height being higher than the first height.

3. The nacelle according to claim 1, wherein said dome cover element comprises at least three linear edges.

4. The nacelle according to claim 1, wherein said dome cover element comprises at least one drain hole.

5. The nacelle according to claim 1, wherein said nacelle comprises sealing means adapted for sealing said dome cover element in both first and second configurations.

6. The nacelle according to claim 1, wherein said dome cover element comprises fiberglass or steel.

7. The nacelle according to claim 1, wherein said wind turbine nacelle further comprises a lower cover part having a bottom cover and two opposite side covers defining a space and a width of the bottom cover part.

8. The nacelle according to claim 1, wherein each of said multiple cover elements comprises at least one flange for connecting to another of said multiple cover elements.

9. The nacelle according to claim 1, wherein the height (H.sub.n) of said wind turbine nacelle in said first configuration is equal to or lower than 4 m.

10. The nacelle according to claim 1, wherein the height (H.sub.d) of said dome cover element is at least 10 cm.

11. The nacelle according to claim 1, wherein said wind turbine nacelle comprises: arranged to be connected to the wind turbine tower and adapted for housing the rotor-supporting assembly, and at least one auxiliary unit for example housing an operative component forming part of the power conversion assembly, wherein the main unit and the auxiliary unit are separate units configured to be connected by a unit fixation structure at an interface, and wherein said main unit comprises said top cover comprising multiple cover elements, of which at least one is a dome cover element comprising a dome-shaped part.

12. The nacelle according to claim 1, wherein said nacelle comprises a main unit and at least two auxiliary units. .

13. The nacelle according to claim 11, wherein the main unit and the at least one auxiliary unit are arranged side by side in a direction away from a rotational axis defined by the rotor-supporting assembly.

14. The nacelle according to claim 1, wherein said wind turbine nacelle houses a rotor-supporting assembly for supporting a hub.

15. The nacelle according to claim 1, wherein said wind turbine nacelle houses a power conversion assembly.

16. A reconfiguration method for the wind turbine nacelle according to claim 1, the method comprising the steps of: providing a nacelle in a first configuration in which said dome-shaped part protrudes downwards or a second configuration in which said dome-shaped part protrudes upwards; and shifting the configuration to the other of said first configuration and said second configuration.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In the following, embodiments of the disclosure will be described in further details with reference to the accompanying schematic drawings which, for the purpose of illustration, show some non-limiting embodiments and in which:

[0028] FIG. 1 shows a wind turbine;

[0029] FIG. 2 shows a nacelle of a wind turbine;

[0030] FIG. 3 shows a perspective view of the nacelle of FIG. 2;

[0031] FIG. 4 shows a nacelle of a wind turbine in a second configuration;

[0032] FIG. 5 shows a nacelle of a wind turbine in a first configuration; and

[0033] FIGS. 6a-6d schematically show the method of changing from one configuration to the other.

DETAILED DESCRIPTION OF INVENTION

[0034] The detailed description and specific examples, while indicating embodiments, are given by way of illustration only, since various changes and modifications will become apparent to those skilled in the art from this detailed description.

[0035] FIG. 1 illustrates a wind turbine 1 with a nacelle 2 mounted on a tower 3. A hub 4 (hereafter, hub is used to refer to hub in itself or hub and spinner for those wind turbines, where there is a spinner surrounding the hub) carrying three rotor blades 5 forms a rotor and is carried by a rotor-supporting assembly in the nacelle 2. The hub with rotor blades is always turned to face the wind and the turning movement is performed in a yaw of the bottom of the nacelle in the connection with the tower. Typically, the rotor-supporting assembly comprises a rotor shaft connecting a gear arrangement and a generator to the hub.

[0036] FIG. 2 illustrates that the nacelle in a second embodiment comprises a main unit 20 and two auxiliary units 21, 22. A cooling area 23 is arranged on top of the nacelle. The cooling area is formed by a heat exchanger which may form part of the main unit, and/or any of the auxiliary units. The main unit 20 is mounted on the tower 3 via a yawing arrangement (not shown), allowing the nacelle 2 to rotate in order to direct the rotor into the wind.

[0037] FIG. 3 illustrates a perspective view of the nacelle 2 of FIG. 2. In FIG. 3 the outer walls of the nacelle 2 are (for the sake of explanation) transparent, thereby revealing the interior parts of the nacelle 2 and the wind turbine components accommodated therein. The main unit 20 accommodates a main bearing unit 31 supporting a main shaft for rotation therein, a gear arrangement 32 and a generator 33, arranged sequentially behind the hub 4, along a direction defined by the rotational axis of the hub 4. The components in the main unit primarily form part of the drivetrain.

[0038] It can be seen from the position of the main bearing unit 31 that the rotational axis of the hub 4 is slightly inclined relative to horizontal. This in combination with the hub having a large diameter compared to front side of the main unit 20 results in a dome shape 24 being required on the upper side of the main unit.

[0039] The auxiliary unit 22 accommodates a transformer unit 34, and a converter unit 35 which herein constitute two different operative components being accommodated in the auxiliary unit but carried by the main unit. In alternative embodiments, the operative component could be a power conversion assembly such as an electrolysis cell stack, a battery.

[0040] Each auxiliary unit 21, 22 is mounted along a side of the main unit 20 by a unit fixation structure. In the disclosed embodiment, they are mounted in such a manner that one auxiliary unit 21 is mounted along a right side of the main unit 20 and the other auxiliary unit 22 is mounted along a left side of the main unit 20, as seen in a direction along a rotational axis of the hub 4 from the hub 4 towards a rear wall of the main unit 20.

[0041] FIG. 4 shows a schematic view of a nacelle 20,40 of a more traditional type of wind turbine, where a single nacelle contains all elements needed without additional auxiliary units. The invention will now be further described with reference to a nacelle of this type.

[0042] The nacelle 40 usually has a cover in order to protect the interior parts of the nacelle. The cover may comprise elements attached to an internal frame or be a self-supporting construction carrying its own weight.

[0043] In an embodiment of the present invention, the nacelle 40 has a top cover comprising of multiple cover elements. Cover elements 41, 42, and 43 may or may not be identical, but most importantly dome cover element 44 comprises a dome-shaped part 45 with the dome-shaped part protruding upwards.

[0044] Further, the nacelle has a lower cover part having a bottom cover 50 and two opposite side covers 51 defining a space 52 and a width W of the bottom cover part.

[0045] FIG. 5 shows a schematic view of the nacelle of FIG. 4, in which the dome cover element 44 is in a first configuration in which said dome-shaped part 45 protrudes downwards, i.e. a transportation configuration. This is opposed to the assembled configuration as in FIG. 4. In this transportation configuration, the dome-shaped part 45 is within the space 52 of the lower cover part so that the overall height of the nacelle is reduced to comply with the transport restrictions in e.g. Europe and USA. As shown, the height of the nacelle in the assembled configuration is H.sub.n and in the transportation configuration, the height is H.sub.n+H.sub.d.

[0046] In prior art solutions where a higher part is removed and transported separately or placed inside the nacelle during transportation, the removal of the higher part creates an opening in the nacelle roof. This opening will be subject to rain and dirt whirled around during transport entering the interior of the nacelle unless covered somehow. For this reason, typically a tarpaulin is used to cover the opening.

[0047] In some prior art, such tarpaulin can only be used once as it will suffer too much damage during transport, and has to be discarded. In other cases, such tarpaulin is strengthened markedly but then has to be shipped back from site after the dome roof is installed to be reused.

[0048] Consequently, as the dome cover element 44 will cover the opening in the nacelle during transport, thus closing off the interior of the nacelle and further making a tarpaulin expendable, the present invention is advantageous both in relation to saving costs and being environmentally friendly.

[0049] FIGS. 6a-6d schematically show the method of changing from one configuration to the other of the wind turbine nacelle. FIG. 6a shows the nacelle in a first configuration (transport configuration), FIG. 6b shows the dome cover element 44 comprising the dome-shaped part 45 being lifted. Between FIGS. 6b and 6c, the dome cover element 44 is rotated 180, and FIG. 6c then shows the dome cover element 44 comprising the dome-shaped part 45 being lowered. Finally, in FIG. 6d the nacelle is in a second configuration (assembled configuration).

[0050] With small arrows in FIGS. 6a and 6d are indicated very roughly approximate force vectors of how gravity will influence the dome-shaped part 45. Clearly the forces acting on it will be different between the two configurations. Therefore, it is required to design the dome cover element 44 including the dome-shaped part 45 such that it can handle the forces acting on it both in the upwards and downwards configurations. This can be done through additional stiffening in the right places of the dome cover element 44.

[0051] As mentioned, in some prior art a higher part may be transported inside of the nacelle to avoid double transport costs. However, if so the higher part will take up space inside the nacelle. With the present invention, the main part of the space inside the nacelle is available for other purposes.

[0052] When herein the term dome-shaped is used, it is to be understood as the dome cover element having a part protruding from a generally flat upper surface to establish a generally smooth transition between the upper surface of the nacelle and the rotor as seen for example in FIG. 2. This protruding part may typically be in the shape of a dome (rounded), but it may also be protruding in other shapes, such as a wedge-shaped element having the higher end towards the rotor.

[0053] Although the invention has been described above in connection with preferred embodiments of the invention, it will be evident for a person skilled in the art that several modifications are conceivable without departing from the invention as defined by the following claims.