METHOD FOR HARVESTING OVERHEAD WIND ENERGY

Abstract

The invention relates to a method of harvesting overhead wind energy with greater efficiency and being better in terms of manufacturing technology and equipment installation. In particular, the invention relates to a method of harvesting overhead wind energy with an equipment system for indirectly catching wind, the method comprises: catching overhead wind; guiding the caught overhead wind downwards; converting the energy of the caught wind into mechanical work to rotate one or more generators on the ground.

The cost of the equipment system for indirectly catching wind is much cheaper than those of the traditional wind electricity pylon.

Claims

1. A method of harvesting overhead wind energy with an equipment system for indirectly catching wind, the method comprises: catching overhead wind; guiding the caught overhead wind downwards; converting the energy of the caught wind into mechanical work to rotate one or more generators, wherein the equipment system for indirectly catching wind comprises: an overhead wind catcher (1) with a flare inlet and a narrow outlet (3) to increase the velocity of the wind caught and guided downwards; a tail vane (2) attached to the overhead wind catcher (1) to orientate the latter towards the wind direction; a windbreak cover (4); a wind duct (10) to guide the caught wind downwards; a high efficiency air turbine; optionally an air exit chamber (12); and an operation station (13) on the ground to encompass all parts of the wind engine and other auxiliary structures.

2. The method according to claim 1, wherein the high efficient air turbine is an air turbine (11) arranged in the vertical direction, and the air exit chamber (12) is present.

3. The method according to claim 1, wherein the air turbine is an air turbine (11) arranged in the horizontal direction, the equipment system further comprises a wind deflector elbow (14) and the air exit chamber (12) is removed so that the wind can self-exit in a specified direction, the equipment system also further comprises a vertical axis wind engine (15) with a high efficiency 80% arranged right behind the air turbine (11) to take advantage of the energy of low velocity wind.

4. The method according to claim 3, wherein the equipment system further comprises an additional wind engine of the vertical axis principle (17) but being arranged in the horizontal direction on an axis (18), just above the wind deflector elbow (14).

5. The method according to claim 1, wherein the air exit chamber (12) is absent, and the high efficient air turbine is a flat blade air turbine (20) having a shaft (21) working in a manner similar to the principle of hydraulic turbines used in hydroelectricity to prolong the time for exchanging the energy with the turbine blades.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The purposes, advantages and other aspects of the present invention will become obvious in the following detailed description with the reference to the accompanying drawings, where:

[0035] FIG. 1 shows a typical overhead horizontal axis wind engine with 3 blades attached to a nacelle at their back side.

[0036] FIG. 2 depicts a wind duct with a cross section that varies according to Betz's conditions.

[0037] FIGS. 3a-3d show the movement of the airflow through the blades of the wind engine in two different states and the diagrams for analyzing wind pressures applied on the blades.

[0038] FIGS. 4a-4c are 3D images showing a specific example of a wind catcher 1 with a tail vane 2 and a windbreak cover 4.

[0039] FIG. 5a depicts a cross-section of a proposed air turbine and FIG. 5b is a picture of a steam turbine model that can be modified to be that air turbine.

[0040] FIG. 6a depicts an overall arrangement diagram of an equipment system for indirectly catching wind used in the overhead wind energy harvesting method, wherein an air turbine 11 is arranged in the vertical direction, while FIGS. 6b and 6c are the front view and the lateral view, respectively, of the equipment system having the arrangement shown in FIG. 6a.

[0041] FIG. 7a depicts the overall arrangement diagram of another equipment system for indirectly catching wind used in the overhead wind energy harvesting method, wherein the air turbine 11 is arranged in the horizontal direction and the equipment system further comprise a vertical axis wind engine 15, while FIGS. 7b and 7c are the front view and the lateral view, respectively, of the equipment system having the arrangement shown in FIG. 7a.

[0042] FIG. 8a and FIG. 8b are the front view and the lateral view, respectively, of the equipment system substantially same as those in FIG. 7, but further provided with a vertical axis wind engine 17 arranged in horizontal direction in front of the wind deflector elbow 14.

[0043] FIG. 9a and FIG. 9b are the front view and the lateral view, respectively, of the equipment system substantially same as those in FIG. 6, but the air turbine 11 that arranged in the vertical direction is replaced with an air turbine 20 within which the air flows in a circular direction in a manner similar to the principle of hydraulic turbines used in hydroelectricity.

DETAILED DESCRIPTION OF THE INVENTION

[0044] Next will be a detailed description of the method of harvesting overhead wind energy based on the accompanying FIGS. 1-9.

[0045] As mentioned above, the blades of the overhead wind engine have been designed to be longer and longer to increase the wind-catch power. The longer the blades are, the higher the wind engine must be arranged, this makes the structure increasingly cumbersome and heavier, while the blade's wind-catch efficiency .sub.CQ is just under 5%. Therefore, to overcome the disadvantages of the prior art, the present invention provides a method of harvesting overhead wind energy with an equipment system for indirectly catching wind, that is, the wind is caught and guided downwards along the wind duct, then the energy of the caught wind is converted by the wind engine to mechanical work to rotate one or more generators. In an embodiment, the equipment system for indirectly catching wind used in the overhead wind energy harvesting method is schematically presented in FIG. 6a, and detailedly presented in FIG. 4, FIG. 6b and FIG. 6c, the equipment system includes: [0046] an overhead wind catcher 1 with a flare inlet and a narrow outlet 3 to increase the velocity of the wind caught and guided downwards; [0047] a tail vane 2 attached to the overhead wind catcher 1 to orientate the latter towards the wind direction; [0048] a windbreak cover 4; [0049] a wind duct 10 to guide the caught wind downwards; [0050] a high efficiency air turbine 11 arranged in vertical direction; an air exit chamber 12; and [0051] an operation station 13 on the ground to encompass all parts of the wind engine and other auxiliary structures.

[0052] Here, the wind catcher with the cross section S.sub.Ch which is only equivalent to the total dynamic wind-catch cross section ns.sub. imparts a rotating torque of being exactly equal to .sub.CQS to the blades, i.e. its power is just equivalent to only to 1/2.5 of the power value announced by wind engine manufacturers. However, the commercial electrical production remains unchanged because the commercial electricity generation time, which is correctly assessed according to the actual windy time in the year, is greater than 2.5 to 3 times. This assures that the project is still profitable in practice.

[0053] To reduce the size of the components to be assembled with the wind catcher 1, it is possible to structurally calculate the wind catcher 1 so that its outlet wind velocity is N times greater than the inlet wind velocity. Through the wind duct 10 with the cross section S.sub.OD S.sub.Ch/N, the wind energy is now guided downwards to the ground to run the air turbine 11 located there. Because the wind has been concentrated into a flow within the wind duct, the wind engine can be of any type provided that it could have the highest efficiency (i.e. over 80%) and not necessarily be the horizontal axis wind engine (of which the efficiency is only <5%) to withstand the windstorm. The air exit chamber 12 is calculated so as to have the minimal aerodynamic resistance and the minimal loss, and to be suitable with the installation site.

[0054] In this embodiment, because the air turbine 11 is arranged in the vertical direction, the structure is relatively compact, taking up less space, but in return, it is more difficult for manufacturing and maintenance.

[0055] In another aspect, to overcome the above disadvantages, it is possible to arrange the air turbine 11 in the horizontal direction as shown in FIGS. 7b and 7c. At this point, a wind deflector elbow 14 is required, and the air exit chamber 12 is no longer needed as the wind has already self-exited in a specified direction. Therefore, a vertical axis wind engine 15 with a high efficiency 80% can be further provided right behind the air turbine 11 having the oriented wind to take advantage of the energy of low velocity wind after passing through the said air turbine to run the generator II according to the diagram in FIG. 7a.

[0056] At this time, the presence of the wind deflector elbow 14 causes an energy loss of the wind entering the air turbine 11.

[0057] In another aspect, to overcome this situation, it is possible to have an additional wind engine of the vertical axis principle 17 but being arranged in the horizontal direction on an axis 18, just above the wind deflector elbow 14 as shown in FIGS. 8a and 8b. At that time, it will be necessary to connect up to three generators, making the structure complicated.

[0058] In another aspect, to overcome this shortcoming, it is possible to simply use an air turbine 20 having a shaft 21, within which the air flows in a circular direction in a manner similar to the principle of hydraulic turbines used in hydroelectricity as shown in FIGS. 9a and 9b. Here, since the air flows along a circular arc path, the time for the energy exchange with the turbine blades is prolonged.

Effect of the Invention

[0059] The method of harvesting overhead wind energy according to the present invention comes from a more accurate determination of the wind engine efficiency which is very low and therefore allows the implementation of an equipment system for indirectly catching wind, rather than directly installing overhead equipments. This helps to greatly reduce the costs of overhead wind engine including the transportation, installation and maintenance costs.

[0060] Although the invention has been described in detail for several implementations, it is important for a person skilled in the art to understand that various modifications can be made that are not outside the scope of the invention's protection.