The invention relates to a vertical axis wind turbine, an energy generation assembly and a method for generating energy using a vertical axis wind turbine.

Vertical axis wind turbines (VAWTs) are known from practice and are applied in various types and sizes. In practice, vertical axis wind turbines are especially known to be used in smaller sizes, the so-called small vertical axis wind turbines (or SVAWTs). The common feature of such wind turbines is that the main rotor shaft extends in vertical direction, which means that it generally is transverse to the (mainly horizontal) wind direction. An advantage thereof is that many components of the turbine, including the generator and gearbox, can be located close to the ground. As a result, the component are easier to access to perform maintenance.

A disadvantage is that the unit cost of the produced electricity for vertical axis wind turbines, and especially for small vertical axis wind turbines, is relatively high. Therefore, there is a need for a more efficient vertical axis wind turbine.

The present invention is aimed at providing a more efficient vertical axis wind turbine, and thereto provides a vertical axis wind turbine comprising: a shaft that extends along a longitudinal axis; a rotor that is rotatably attached to the shaft and comprises a number of rotor blades; at least two wind guides that, when viewed along the longitudinal axis, are positioned on opposite sides of the rotor, wherein each wind guide has a wind guide surface that faces the rotor such that the wind guide surfaces form a wind duct; and the wind guide surfaces are tiltable with respect to the longitudinal axis to adapt a height of the wind duct.

The height of the wind duct of the vertical axis wind turbine according to the invention is, as described above, adaptable by using the tiltable wind guide surfaces. In other words, the wind guide surfaces are tiltable with respect to the longitudinal axis to narrow the wind duct down or widen the wind duct up compared to a rest position in which the wind guide surfaces, and/or the wind guides, are not tilted. The narrowing or widening depends on the direction of tilting of the tiltable wind guide surfaces.

It is noted that in this application the words tilt/tilted, slant/slanted, rotatable/rotated and/or pitch/pitched are used interchangeably and in general have a similar meaning. This is to indicate an angle or change in angle between the wind guide surface and the longitudinal axis. The wind guide surfaces, and preferably the wind guides, are movable between an primary, untilted position to a tilted position in which the wind guide surfaces are closer together at the side of the wind direction.

It is noted that the tilted position can be one of many possible tilted positions. In other words, the tilt angle can be varied over a large range to create a desired tilted position.

An advantage of the vertical axis wind turbine according to the invention is that, due to the tiltable wind guides, the height of the wind duct is adaptable to the specific circumstances. More specifically, the wind speed towards the rotor can be advantageously be increased by tilting the wind guide surfaces towards each other on side of the dominant wind direction. This increases the efficiency of the turbine.

It is noted that when the phrase ‘dominant wind direction’ is used, it refers to the wind direction that provides the wind for rotation of the rotor at that particular time and which generally is the wind direction having the highest wind intensity.

Another advantage is that the wind guides are tiltable in 360 degree arc, thus in any direction that at that time is the dominant wind direction.

A further advantage is that the use of wind guides having a tiltable wind guide surface provides a simple and effective construction that obviates the need for large construction to guide the wind (and increase the wind speed) towards the rotor.

In an embodiment according to the invention, the wind guides have a central point that coincides with the longitudinal axis, wherein the wind guides and their associated wind guide surface are tiltable with respect to this central point.

An advantage is that the wind guide surfaces can be tilted relatively easy and substantially at any point along a 360 degree arc. This provides an improved flexibility with regard to the wind direction.

Another advantage is that this relatively simple construction obviates the need for complex structures, and therewith reduces manufacturing and/or operating costs.

Yet another advantage is that the application of the wind guides results in an increased energy production from the wind turbine with a smaller rotor. This is achieved by the fact that the turbine can produce more efficiently. In addition, a reduction in size of the rotor (and thus the turbine) also reduces costs of the turbine and results in less space being occupied.

In an embodiment according to the invention, the wind guides are tiltable with an angle a in the range of 0° to 60°, preferably in the range of 0° to 45°, and more preferably in the range of 0° to 30°

The increase in wind speed in the wind duct is depends on the height and the length of the wind duct, which are positively influenced using the tiltable wind guide surfaces. It has been found that the tilt angle most preferably is in in the range 0° to 30° in order to achieve a good balance between the increases in wind speed on the one hand and the efficiency of the rotor on the other hand. However, an increase in the effect is already noticeable in the broadest range mentioned above. Furthermore, the tilt angle of 0° must be understood as the primary position, whereas angle above or about 0° is understood to provide a tilt to the wind guide surfaces and/or the wind guides.

In other words, the wind speed in the wind duct can be regulated using the tilt angle of the wind guide surfaces.

In an embodiment according to the invention at least one, preferably all, of the wind guides is a hemisphere and the associated wind guide surface is the spherical surface of the hemisphere.

An advantage of a spherical wind guide surface is that it is provided with an equal shape at any point along its perimeter. As a result, the wind guide surfaces can be tilted in any direction along the perimeter to achieve the beneficial effect of the invention.

Another advantage is that the spherical surface, even without being tilted, provides excellent guidance of the wind flow towards the rotor.

A further advantage is that, due to the shape of the wind guide, the starting torque required by the wind turbine is reduced, which enables energy production even at low wind speeds. This increases the efficiency of the turbine in terms of output.

It is preferred that, especially in this embodiment, the wind guide surface is tilted by tilting the wind guides. It is however noted that it is also possible to tilt the wind guide surface by merely tilting a part of the wind guide.

In an embodiment according to the invention at least one of the wind guides is a hollow hemisphere with an at least partially open base surface.

An advantage of providing a hollow, open hemisphere, especially as an upper wind guide, is that the concave inner surface of the wind guide can be provided with solar cells or solar panels and/or can be used as a water collection reservoir to collect rain for (re)use.

Another advantage of providing the wind guides as hollow, open hemispheres is that it reduces the amount of material required for the turbine and therewith reduces costs.

A further advantage of a hollow, open hemisphere is that it has a relatively high strength.

In an embodiment according to the invention, the hemispherical wind guides have a central point that is positioned on the longitudinal axis, wherein the central point is a tilting point for the tiltable wind guides.

An advantage of the abovementioned construction is that the wind guides, and therewith the wind guide surfaces, can be tilted in any direction along the 360 degree perimeter or circumference of the hemisphere. This provides increased flexibility, because it can be used with any particular dominant wind direction. In an embodiment according to the invention, the wind turbine may further comprise and/or be communicatively coupled to at least one wind sensor that is configured to determine, preferably real-time, a dominant wind direction.

An advantage of providing at least one wind sensor is that sensor data can be collected. The dominant wind direction can be established using the collected sensor data, after which the wind turbine can be positioned to maximize the wind speed to the rotor. Alternatively, the sensor data can directly encompass the dominant wind direction.

Another advantage is that the at least one wind sensor may additionally be used to monitor the wind speed, preferably the wind speed from the dominant wind direction. This information can subsequently be used to determine, for example using a processor and/or software, the optimal position of the wind guide surfaces to maximize the energy output and/or to minimize wear on the components while providing an energy output that is as high as possible.

In an embodiment according to the invention, the vertical axis wind turbine further comprises a processor that is configured to perform one or more of: determining, based on sensor data received from the at least one wind sensor, a dominant wind direction; calculating, based on sensor data received from the at least one wind sensor and/or based on the dominant wind direction, an optimal tilt angle of the wind guide surfaces and/or the wind guides; predicting, based on weather data and sensor input received from the at least one wind sensor, an optimal positioning and/or tilt angle of the wind guide surfaces and/or the wind guides for at least one future time point and/or time period; and operatively controlling the wind guides and/or the wind guide surfaces to position the wind guide surfaces in the optimal tilt angle.

An advantage of the abovementioned embodiment is that the operation of the vertical axis wind turbine according to the invention can be optimized in terms of energy yield. This is especially true with regard to the positioning of the wind guides and, in particular, the tilt angle of the wind guide surfaces and/or the wind guides. This can be performed real-time or may be performed based on combination of real-time and historical data.

In an embodiment according to the invention, the vertical axis wind turbine comprises at least one tilting mechanism that is operatively coupled to the wind guides for tilting the wind guides, and preferably wherein each wind guides is provided with an associated tilting mechanism.

In order to tilt the wind guide surfaces, it is preferred that the wind guides are provided with a tilting mechanism. Tilting the wind guide will than automatically result in a tilt of the wind guide surfaces to the desired angle. This construction is reliable and relatively simple, which is advantageous in respect of durability and life time.

It may also be possible to provide an embodiment in which the wind guide surfaces are constructed to be moveable, that is tiltable, with respect to the wind guides and the rotor. This may for example entail a number of movable panels that together are part of the wind guide and form the wind guide surface.

In an embodiment according to the invention, the tilting mechanism is a mechanical tilting mechanism that is connected to the wind guide and the shaft to enable the wind guide to be tilted with respect to the shaft.

An advantage of coupling the wind guide and the shaft using the tilting mechanism is that the wind guide, and thus the wind guide surface, can be tilted in a precise and reliable manner.

In an embodiment according to the invention, the vertical axis wind turbine may further comprise one or more solar cells, wherein at least one of the one or more solar cells is positioned on the wind guide surface of the at least two wind guides.

An advantage of providing solar cells on the vertical axis wind turbine according to the invention is that a hybrid vertical axis wind turbine is achieved with which energy can be generated by both wind power and solar power. This increases the efficiency of the vertical axis wind turbine even further.

It also provides that energy can be generated even in case one of the energy sources is not available (due to lack of wind or lack of sun).

In an embodiment according to the invention, the vertical axis wind turbine comprises and/or is communicatively coupled with at least one light sensor that is configured to determine, preferably real-time or periodically, a (solar) light influx.

An advantage of providing one or more light sensors is that the influx of sunlight can be determined. The sensor data comprising the magnitude of the influx of (sun)light can subsequently be used to position the solar cells of the vertical axis wind turbine to capture a maximum amount of sunlight. The positioning of the solar cells is performed by adjusting the tilt angle of the wind guides and/or the wind guide surfaces. This is especially relevant in periods in which the wind strength is relatively low.

In an embodiment according to the invention at least one of the wind guides comprises a drain hole for draining water from the wind guide.

An advantage of providing a drain hole is that any water accumulated on or in the wind guide can be removed. This is especially relevant if the wind guide, in particular an upper wind guide, is a hollow wind guide having an opening. In this opening, which would be directed in an upward direction, water can accumulate, for example by condensated water or rain. In order to prevent damage, such water can be easily drained via a drain hole. Another advantage is that such accumulated water may in some cases also be used for other purposes, including for example a car wash, an outdoor tap point or other suitable uses.

In an embodiment according to the invention the at least two wind guides comprise an upper and a lower wind guide that, in use of the vertical axis wind turbine, are respectively positioned above and below the rotor.

In a preferred embodiment, two wind guides are used, which are positioned above and below the rotor. In case the wind guides would be provided with a hemispherical wind guide surface, these surface would be facing each other and the rotor.

The wind guides may be positioned directly adjacent or at a short distance of the rotor.

In an embodiment according to the invention the drain hole is provided in the upper wind guide.

An advantage of at least providing the drain hole in the upper wind guide is that water, for example condensated water or rain, that accumulates in or on the wind guide, can be easily drained away via the drain hole.

Another advantage is that such accumulated water may in some cases also be used for other purposes, including for example a car wash, an outdoor tap point or other suitable uses.

In an embodiment according to the invention at least one solar cell is provided on the wind guide surface of the lower wind guide, and/or wherein the upper wind guide is a hollow hemisphere with an at least partially open base surface, and wherein at least one solar cell is provided on an inner surface of the upper wind guide.

An advantage of providing solar cells on the vertical axis wind turbine according to the invention is that a hybrid vertical axis wind turbine is achieved with which energy can be generated by both wind power and solar power. This increases the efficiency of the vertical axis wind turbine even further.

It also provides that energy can be generated even in case one of the energy sources is not available (due to lack of wind or lack of sun).

The positioning of the solar cells on the lower wind guide surface is beneficial, because the solar cells will then be directed upwards towards the sun. Similarly, it is beneficial if the solar cells are positioned on the (concave) surface of the upper wind guide, because it also provides upwardly directed solar cells. In both cases, optimal use can be made of the solar influx.

In an embodiment according to the invention in which the wind guides are provided with solar cells and at least one light sensor, the vertical axis wind turbine further comprises a processor that is configured to perform one or more of: determining, based on sensor data received from the at least light sensor and/or based on actual and/or future weather data, a position of the sun; calculating, based on sensor data received from the at least one light sensor and/or based on actual and/or future weather data, an optimal tilt angle of the wind guide surfaces and/or the wind guides to capture the maximum solar influx for at least one future time point and/or time period; and/or operatively controlling the wind guides and/or the wind guide surfaces to position the wind guides in the optimal tilt angle.

An advantage is the operation of the vertical axis wind turbine according to the invention can be optimized with respect to the energy yield from the solar panels due to an optimal positioning of the wind guide surfaces. The optimal positioning may be provided based on (actual) light sensor data, yet also may be calculated form actual and/or future weather data or a combination thereof.

In an embodiment according to the invention, the device may comprise a processor that is configured to: determine, based on sensor data received from the at least light sensor, a present position of the sun; determine, based on sensor data received from the at least one wind sensor, a dominant wind direction; calculating, based on the sensor data received from the at least one light sensor and the at least one wind sensor, an optimal tilt angle of the wind guide surfaces to maximize the combined energy yield from wind and sun; and adapting the position of the wind guides to the optimal tilt angle.

An advantage of the abovementioned embodiment is that the maximum energy yield can be calculated by calculating both the energy yield from the solar cells as well as the energy yield from the wind turbine and subsequently calculating the optimal tilt angle to provide the maximum combined energy yield from both sources. The efficiency of the device is therewith increased relative to existing wind turbines.

Additionally or alternatively, the optimal tilt angle for the combined energy yield from both wind and sun can be based on actual and/or future weather data.

An advantage of the using actual and/or future weather data is that the processor is capable of calculating the optimal tilt angle for the wind guides to optimize the combined energy production from both solar cells and wind turbine.

In an embodiment according to the invention, the rotor blades may be helically shaped and extend substantially in the longitudinal direction.

It has been found that helically extending blades have an improved lifetime compared to non-helical blades. Another advantage is that helical blades are more efficiently capturing the wind and therewith produce more energy than conventional non-helical blades under the same circumstances.

A further advantage is that, due to the shape of the wind guide, the starting torque required by the wind turbine is reduced, which enables energy production even at low wind speeds. This increases the efficiency of the turbine in terms of output.

In an embodiment according to the invention, the number of rotor blades may be in the range of two to five, and preferably is three.

The invention further relates to an energy generation assembly comprising: at least one vertical axis wind turbine according to the invention; and at least one energy storage means.

The energy generation assembly has similar advantages and effects as the vertical axis wind turbine according to the invention. It is noted that the embodiments described for the vertical axis wind turbine according to the invention may, alone or in combination, also be used in or applied with the energy generation assembly according to the invention.

An advantage of the energy generation assembly according to the invention is that it allows the generated energy to be stored for later use. This improves the operational time and further increases reliability.

In an embodiment of the energy generation assembly according to the invention, the assembly may further comprise at least one charging station configured for charging electric vehicles and/or a grid connector configured to connect the energy generation assembly to an electricity grid.

An advantage of the abovementioned embodiment is that it provides local and sustainable energy for charging electric vehicles and/or off-grid solutions. This is especially relevant to reduce the carbon footprint of electric vehicles (EV) by obviating or at least significantly reducing the amount of fossil-based (or ‘grey’) electricity for EVs.

It is advantageous to also provide a connection to the electricity grid if possible to allow generated electricity to be fed into the grid if demand of the electric charging stations is low.

In an embodiment of the energy generation assembly according to the invention, the energy storage means is may be battery, or the energy storage means may comprise a hydrogen generator and a hydrogen tank.

An advantage of an energy storage system using batteries and/or hydrogen storage means is that the generated energy can be stored for later use. This allows the sustainable energy to be used for charging EVs even if the amount of generated energy is lower than the demand at a specific time. In addition, the storage system serves to balance demand and supply at any given time. It is noted that such energy storage is also interesting in remote or off-grid locations, in which the generated energy is used for other means than (only) charging EVs. In an embodiment of the energy generation assembly according to the invention, the energy generation assembly may further comprise a water storage means that is operatively connected to the drain hole and a water supply means that is configured for supplying water from the storage means to a user.

An advantage of the abovementioned embodiment is that it provides an even more sustainable assembly, because it generates sustainable energy while simultaneously allowing water capture.

The captured water may be used for various purposes at an energy supply station (i.e. gas station) or, in case of off-grid or remote use of the assembly, as a source of useable water. This may for example include purposes as gardening or flushing water for toilets.

The invention further relates to a method for increasing the energy yield from a vertical axis wind turbine, the method comprising the steps of: providing a vertical axis wind turbine according to the invention; and increasing or decreasing a height of the wind duct by adjusting an angle of the wind guides surfaces with respect to the longitudinal axis.

The method according to the invention has similar advantages and effects as the vertical axis wind turbine and the energy generation assembly according to the invention. It is noted that the embodiments described for the vertical axis wind turbine and/or the energy generation assembly according to the invention may, alone or in combination, also be used in or applied with the method according to the invention.

In an embodiment of the method according to the invention, the step of increasing or decreasing a height of the wind duct comprises: determining, preferably using one or more wind sensors, a dominant wind direction; adjusting the angle of the wind guides surfaces to decrease the height of the wind duct facing the dominant wind direction.

An advantage of the abovementioned embodiment is that the height of the wind duct is adapted real-time, or at least periodically, to the dominant wind direction. As a result, the wind speed, and therewith the efficiency of the turbine, is continually optimized.

A further advantage is that the sensor data, which may include wind speed data, is usable to, periodically or even real-time, control the height of the wind duct to optimize the energy production from the vertical axis wind turbine.

It is preferred that the vertical axis wind turbine comprises a processor and that the steps of the method according to the abovementioned embodiment comprise computer- implemented steps. In other words, the processor is configured to process information for the step of determining and/or to control a tilting or movement mechanism of the vertical axis wind turbine to adjust the angle of the wind guides and/or wind guide surfaces. It is noted that a real-time adaptation may be construed as a continuous process of adaptation, yet in this application also includes a periodic adaptation based on the wind sensor data. This may for example be after a predetermined period of time and/or based on a predetermined threshold of change in the wind sensor data.

In an embodiment of the method according to the invention, the method further comprises the steps of: retrieving, preferably by a software program, weather data from a weather data source; calculating, based on the dominant wind direction determined by the one or more wind sensors and/or the weather data, a predicted optimal tilt angle of the wind guide surfaces and/or the wind guides for a present and/or future time point; adjusting, based on the calculation, the tilt angle of the wind guide surfaces to match the predicted optimal tilt angle.

It is noted that this particular embodiment may also be performed without the step of retrieving the weather data from the weather data source such that the calculating is only based on the dominant wind direction.

It is preferred that the method further comprises computer-implemented steps that allow the positioning (i.e. the tilt angle) of the wind guides and the associated wind guide surfaces to be adapted based on a present and/or future time point. In this respect, a predictive yield is calculated to which the angle or tilt of the wind guide surfaces is adapted. An advantage is that the vertical axis wind turbine is capable of optimizing the tilt angle, and thus reliability and energy yield, without external instructions.

Another advantage is that the supply and demand can be balanced more accurately based on historical and actual data, especially when the vertical axis wind turbine is used an energy generation assembly according to the invention.

In an embodiment according to the invention, the steps of retrieving, calculating and/or adjusting may be performed real-time and/or periodically, wherein periodically preferably comprises a time range of between 1 and 120 minutes, preferably between 1 and 60 minutes and more preferably between 1 and 30 minutes.

In an embodiment according to the invention, the method may comprise the steps of: measuring one or more parameters at a predetermined time T to obtain at least one parameter measurement; comparing the at least one parameter measurement at time T with at least one associated parameter measurement at time T-1 to obtain at least one deviation parameter; setting, for each of the one or more parameters, a deviation parameter threshold; comparing the at least one deviation parameter with the at least one deviation parameter threshold; - when the at least one deviation parameter exceeds the threshold value, at least perform the steps of calculating and adjusting.

The parameters may for example be the wind direction, solar influx and/or an angle of the wind guide surfaces with respect to the dominant wind direction.

An advantage of this embodiment is that the orientation of the wind guide surfaces will automatically and periodically be realigned to the optimal tilt angle to maximize the energy yield from the vertical axis wind turbine. The alignment may be performed for wind energy, solar energy or, preferably, the combination thereof.

Another advantage is that, by only periodically checking whether an adjustment of the tilting angle is required, the energy use of the vertical axis wind turbine is reduced (compared to a real-time, continuous adaptation). This results in a good balance between maximizing the energy yield and reducing the amount of energy required to control the wind guides and/or wind guide surfaces.

It is noted that the time T-1 is a time point that precedes time T, such that the present measurement (at time T) is compared to the last measurement (at time T-1). In other words, present time T becomes time T-1 at the next measurement of the parameter.

The invention also relates to a computer implemented method for optimization the energy production from a vertical axis wind turbine, the method comprising: receiving weather data for the location of the vertical axis wind turbine from a weather data source; determining a dominant wind direction from the weather data; receiving rotor orientation data from the vertical axis wind turbine; comparing the determined dominant wind direction with the rotor orientation; and sending instructions to the vertical axis wind turbine, preferably to a control unit thereof, for rotating the rotor towards the dominant wind direction.

The computer-implemented method according to the invention has similar advantages and effects as the abovementioned vertical axis wind turbine, energy generation assembly and method according to the invention. It is noted that the embodiments described for the vertical axis wind turbine and/or the energy generation assembly and/or the method according to the invention may, alone or in combination, also be used in or applied with the computer- implemented method according to the invention.

It will be apparent to the skilled person that the abovementioned method steps may be performed in the order as given or may be performed in a different order.

An advantage of the computer-implemented method according to the invention is that the rotor is continually provided in the optimal position to maximize the energy yield from the wind turbine. In an embodiment of the computer implemented method in which the vertical axis wind turbine comprises a vertical axis wind turbine according to the invention, the method further comprises the steps of: receiving wind data from the at least one wind sensor of the vertical axis wind turbine; determining a dominant wind direction from the wind data; calculating, based on the wind data received from the at least one wind sensor, an optimal tilt angle of the wind guide surfaces and/or the wind guides.

An advantage of the abovementioned embodiment is that the energy yield is optimized due to the fact that the wind guide surfaces and/or wind guides are continually (re)positioned to the optimal tilt angle.

In a further embodiment of the computer implemented method, the method may further comprise the additional steps of: predicting, based on the weather data and the wind data, an optimal positioning and/or tilt angle of the wind guide surfaces and/or the wind guides for at least one future time point and/or time period; and sending instructions to the vertical axis wind turbine, preferably to a control unit thereof, to operatively control the wind guides and/or the wind guide surfaces to position the wind guide surfaces in the optimal tilt angle for the at least one future time point and/or time period.

An advantage of the abovementioned embodiment is that the optimal tilt angle is calculated in advance, which allows the wind guide surfaces and/or wind guides to be realtime adapted. This optimizes the energy yield from the wind turbine at any given point in time.

In an embodiment of the computer implemented method in which the vertical axis wind turbine comprises a vertical axis wind turbine according to the invention that is provided with solar panels, the method further comprises the steps of: receiving solar influx data from a light sensor of the vertical axis wind turbine; determining, based on the solar influx data and/or the weather data, a present position of the sun; calculating an optimal tilt angle of the wind guide surfaces and/or the wind guides to capture the maximum solar influx sending instructions to the vertical axis wind turbine, preferably to a control unit thereof, to operatively control the wind guides and/or the wind guide surfaces to position the wind guides in the optimal tilt angle.

An advantage of the abovementioned embodiment is that the energy yield from the solar panels is optimized. This is especially relevant during periods in which there is little or no wind, because it allows energy production to continue. In an embodiment of the computer implemented method, the method comprises the steps of: calculating an optimal tilt angle of the wind guide surfaces and/or the wind guides to maximize the combined energy production from the vertical axis wind turbine and the solar panels; and sending instructions to the vertical axis wind turbine, preferably to a control unit thereof, to operatively control the wind guides and/or the wind guide surfaces to position the wind guides in the optimal tilt angle.

An advantage of the abovementioned embodiment is that the energy yield is optimized by providing the optimal mix between solar and wind energy. The method according to the invention advantageously calculates which tilt angle would provide the maximum energy yield from both sources together.

In an embodiment of the method for optimization according to the invention, the method further comprises the steps of: receiving energy consumption data at least comprising present energy consumption for a location; receiving battery capacity data from at least one battery; receiving grid availability data; determining, based on the consumption data and the battery capacity data, a first amount of generated energy that can be delivered to the location and/or the battery; sending instructions to the vertical axis wind turbine, preferably to a control unit thereof, to deliver the energy to the location and/or the battery; and optionally determining a second amount of energy that is defined as the generated energy minus the first amount of energy; and further optionally determining, based on the grid availability data, a percentage of the generated energy that can be provided to the grid.

An advantage of this embodiment is that the energy delivered to the grid is based on the grid availability. In known sustainable energy systems, the production is often automatically stopped if the energy yield exceeds the available grid capacity. The abovementioned embodiment may be used to adapt the energy production to the grid availability, thus obviating the need for an (automatic) shut down of the wind turbine. In addition or alternatively, the method allows that the maximum amount of energy is delivered to the grid (based on the grid availability), whereas the remaining amount of energy (if any) is for example delivered to a storage facility, such as a battery.

The invention further relates to a computer program which comprises instructions which, when the program is executed by a computer, cause the computer to carry out the steps of the method for optimization according to the invention. The computer program according to the invention has similar advantages and effects as the abovementioned vertical axis wind turbine, energy generation assembly, method and computer-implemented method according to the invention. It is noted that the embodiments described for the vertical axis wind turbine and/or the energy generation assembly and/or the method and/or the computer-implemented method according to the invention may, alone or in combination, also be used in or applied with the computer program according to the invention.

The invention further relates to a computer readable medium having stored thereon the computer program according to the invention.

The computer-readable medium according to the invention has similar advantages and effects as the abovementioned vertical axis wind turbine, energy generation assembly, method and computer-implemented method according to the invention. It is noted that the embodiments described for the vertical axis wind turbine and/or the energy generation assembly and/or the method and/or the computer-implemented method according to the invention may, alone or in combination, also be used in or applied with the computer-readable medium according to the invention.

In an embodiment of the vertical axis wind turbine according to the invention, the vertical axis wind turbine is provided with means adapted to execute the step of the method for optimization of the energy production.

Further advantages, features and details of the invention are elucidated on the basis of preferred embodiments thereof, wherein reference is made to the accompanying drawings, in which:

Figure 1 shows a perspective view of a first example of a vertical axis wind turbine according to the invention;

Figures 2a and 2b show a schematic cross-sectional view of the example of figure 1 , in which the wind guides are not tilted in figure 2a and are tilted in figure 2b;

Figure 3 shows a perspective view of a second example of a vertical axis wind turbine according to the invention;

Figure 4 shows a perspective view of a third example of a vertical axis wind turbine according to the invention;

Figure 5 shows a schematic overview of an example of a computer-implemented control system for a vertical axis wind turbine according to the invention;

Figure 6 shows a perspective view of a first example of an energy generation assembly according to the invention including a vertical axis wind turbine according to figure 1 ; and

Figure 7 shows a schematic overview of a first example of the method according to the invention.

In a first example (see figures 1 , 2a, 2b), vertical axis wind turbine 2 includes main shaft 4 and rotor 6. Main shaft 4 extends along longitudinal axis A in longitudinal direction z, which in this case is vertical direction z. Rotor 6 in this example is provided with helically shaped rotor blades 8 that substantially extend in longitudinal direction z.

Vertical axis wind turbine 2 further includes first (in this example upper) wind guide 10 having wind guide surface 12 and second (in this example lower) wind guide 14 having wind guide surface 16. Both wind guides 10, 14 have a hemispherical shape of which the spherical surface forms wind guide surfaces 12, 16. Wind guide surfaces 12, 16 together define wind duct 18 that extends between them. Wind duct 18 in this example has height H (see figure 2a), which height H is variable by tilting wind guides 10, 14, therewith bringing wind guide surfaces 12, 16 closer to each other (see figure 2b). This reduces height H and, in use, increases wind speed in wind duct 18 using a venturi effect. This is also clearly visible in figure 2a and figure 2b. In figure 2a, the angle of tilting a or tilting angle a is zero. In figure 2b, the wind guides 10, 14 and particularly the wind guide surfaces 12, 16 are tilted with respect to longitudinal axis A with tilting angle a, which in this example is about 8°

Vertical axis wind turbine 2 further comprises wind sensor 20, which in this example is schematically shown on top of base surface 10a of wind guide 10. Drain hole 22 is schematically shown to be present in upper wind guide 10 to drain water from the hollow inside area of hemispherical wind guide 10.

In a second example (see figure 3), vertical axis wind turbine 102 includes main shaft 104 and rotor 106. Main shaft 104 extends along longitudinal axis A in longitudinal direction z, which in this case is vertical direction z. Rotor 106 in this example is provided with helically shaped rotor blades 108 that substantially extend in longitudinal direction z.

Vertical axis wind turbine 102 further includes first (in this example upper) wind guide 110 having wind guide surface 112 and second (in this example lower) wind guide 114 having wind guide surface 116. Both wind guides 110, 114 have a hemispherical shape of which the spherical surface forms wind guide surfaces 112, 116. Wind guide surfaces 112, 116 together define wind duct 118 that extends between them. Wind duct 118 in this example has height H, which height H is variable by tilting wind guides 110, 114, therewith bringing wind guide surfaces 112, 116 closer to each other. This reduces height H and, in use, increases wind speed in wind duct 118 using a venturi effect.

Vertical axis wind turbine 102 further comprises wind sensor 120, which in this example is schematically shown on top of the spherical wind guide surface 116 of wind guide 114. In this example, upper and lower wind guides 110, 114 are closed hemispheres 110, 114. Lower wind guide 110 is provided, at its base surface 110, with solar cells 124 that provide additional power generation capabilities to vertical axis wind turbine 102.

In a third example (see figure 4), vertical axis wind turbine 202 includes main shaft 204 and rotor 206. Main shaft 204 extends along longitudinal axis A in longitudinal direction z, which in this case is vertical direction z. Rotor 206 in this example is provided with curved rotor blades 208 that substantially extend in longitudinal direction z.

Vertical axis wind turbine 202 further includes first (in this example upper) wind guide 210 having wind guide surface 212 and second (in this example lower) wind guide 214 having wind guide surface 216. Both wind guides 210, 214 have a hemispherical shape of which the spherical surface forms wind guide surfaces 212, 216. Wind guide surfaces 212, 216 together define wind duct 218 that extends between them. Wind duct 218 in this example has height Hs, which height Hs is made smaller by tilting wind guides 210, 214, therewith bringing wind guide surfaces 212, 216 closer to each other (indicated by the white arrows). This reduces height H to height Hs and, in use, increases wind speed in wind duct 218 using a venturi effect.

Vertical axis wind turbine 202 further comprises wind sensor 220, which in this example is schematically shown on the lower central point of spherical wind guide surface 212 of wind guide 210. In this example, lower wind guide 214 is a closed hemisphere 214, whereas upper wind guide 210 is a hollow hemisphere having an open base surface. Upper wind guide 210 is (though not visible in figure 4) provided with solar cells on the concave inner surface of the hemisphere. Lower wind guide 216 is provided with solar cells 224 on wind guide surface 216 that provide additional power generation capabilities to vertical axis wind turbine 202.

In an example (see figure 5), computer-implemented control system 700 for a vertical axis wind turbine according to the invention, such as vertical axis wind turbine 2, 102, 202, 502 contains processor 750 and software program 752. Control system 700 in this example further contains sensors 720, weather data input 754 and, optionally, additional data input 756. Software program 752 is configured to be executed by processor 750 to determine, based on sensor data input from one or more sensors 720, a dominant wind direction. Software program 752 and/or processor 750 is further configured to calculate, based on sensor data input from one or more sensors 720 and preferably additionally based on the dominant wind direction, an optimal tilt angle of the wind guide surfaces and/or the wind guides. Optionally, software program 752 is also configured to predict, based on weather data from weather data input 754 and sensor input from one or more sensors 720, an optimal positioning and/or tilt angle of the wind guide surfaces and/or the wind guides.

In an example (see figure 6), energy assembly 500 comprises vertical wind axis turbine 502, which in this example is similar to vertical axis wind turbine 2. It may however also be one of vertical axis wind turbines 102, 202 or another vertical axis wind turbine according to the invention.

Vertical axis wind turbine 502 is positioned on carrier platform 530, which is supported by support beam 532. Energy assembly 500 further comprises two charging station 534 and energy storage means 536. In an example of method 1000 for increasing the energy yield from a vertical axis wind turbine according to the invention (see figure 7), the method comprises may comprise the step providing 1002 a vertical axis wind turbine according to the invention and increasing 1004 or decreasing 1006 a height H of the wind duct by adjusting an angle of the wind guides surfaces with respect to the longitudinal axis A.

Optionally, step of increasing 1004 or decreasing 1006 a height H of the wind duct may comprises the step of determining 1008, preferably using one or more wind sensors, a dominant wind direction and adjusting 1010 the angle of the wind guides surfaces to decrease the height of the wind duct facing the dominant wind direction.

Further or alternatively, the method may optionally also include the step of providing 1002 a vertical axis wind turbine with a processor and, optionally, a software program that is configured to be executed by the processor. The method further comprises the optional steps of retrieving 1012, preferably by the software program, weather data from a weather data source and calculating 1014, based on the dominant wind direction determined by the one or more wind sensors and/or the weather data, a predicted optimal tilt angle of the wind guide surfaces and/or the wind guides for a present and/or future time point. The method may further comprise the (optional) steps of adjusting 1016, based on the sensor data input, the wind guide surfaces to match the predicted optimal tilt angle.

The present invention is by no means limited to the above described preferred embodiments and/or experiments thereof. The rights sought are defined by the following claims within the scope of which many modifications can be envisaged.