WO2015187006A1

WO2015187006A1 - Wind and wave energy conversion

Info

Publication number: WO2015187006A1
Application number: PCT/NL2015/000013
Authority: WO
Inventors: Soemar Emid
Original assignee: Soemar Emid
Priority date: 2014-06-02
Filing date: 2015-03-24
Publication date: 2015-12-10
Also published as: NL1040829C2

Abstract

Wind energy conversion is combined with a wave energy converter, which is a breakwater against tsunami and storms, suitable to harness the energy of powerful winds and waves, while protecting coastal regions. The added value of the wind turbine-generator according to Fig. 2, a: side view, b: front view, is suggested by its name as WATT (Wind Accelerated Turbo Turbine) engine, to run a water pump for the wave converter or an electricity generator. The engine is self starting, has low wind cut-in, wind speed regulation with wind brake and shut down. The engine runs on other fluids as well, like water, suitable for low currents, free running on buoyancy adjusted turbines, including built-in generators.

Description

Wind and wave energy conversion

The technical field

The invention is in the field of wind energy conversion on a breakwater - wave energy converter. Wave implies water wave, turbine implies only the rotor and turbine-generator rotor with the electricity generator. Hydro means hydro power station with a lake.

Background art

Breakwaters against tsunami and storms were developed in [1] as better alternatives for the traditional ones. Subsequently, the annihilation type breakwater was modified as wave energy converter, called BWEC [2], for electricity generation in normal weather. It can produce electricity at 0.004€/kWh in wave power of 20 kW/m crest; for comparison: hydro 0.04€/kWh and OscillatingWaveColumn-WEC 0.85€/kWh [2]. However, BWEC does not teach how to combine wind energy with wave energy conversion.

The Floating Power Plant A/S (FPP) is the only company in the world, as stated in [3], which combines wind energy and wave energy. It is therefore instructive to learn how that is done. FPP launches the Poseidon37, a 37 m wide by 25 m long floating power plant, with the Front Pivot Hinged Absorber device for the wave energy conversion, with its turbine-generator of 140 kW. The embodiment serves as a floating platform for 1 to 3 wind turbine-generators, type Gaia Wind 133, blade diameter 13 m, 133 m² swept area, rated output 11 kW at the governing wind speed of 11 m/s, 12 m tower height, 18 m including blade radius. The governing wind speed is the lowest wind speed for which the turbine delivers maximum output without overturning the wind turbine. Usually a brake system is therefore necessary to limit the speed. The total rated power is 177 kW for the 37 m wide and 18 m high wind and wave energy converter [4]; it can generate electricity estimated at 0.10 - 0.15€/kWh [5]. This combination of wind and wave power consists of positioning 4 turbine-generators close to each other. Wind turbines do not use the wind over the area (width x height). In [3] the used area is 3 x 133 = 399 m², 60% of the area (37x18 m²). Wind energy conversion is limited to 59.3% (Betz's Limit), for open flow. At a typical wind velocity of 5 m/s Gaia 133 produces 2.2 kW power, i.e. 22% efficiency, it costs 50.000€ each [6]. Wind energy is converted into electricity at an efficiency of , 0.6x22 = 13.2%. The Poseidon37 is not a breakwater, has a cut out for wave of 1.5 m and doesn't teach what to do with more powerful waves. The BWEC is a breakwater against tsunami or storms; it can be at location with powerful waves and water turbine- generators having efficiencies > 90% cost between 400 and 800€/kW.

To improve performance of wind turbine, compared to horizontal axis wind turbines (HAWTs) used in [3], compact wind acceleration turbines (CWATs) have been tried for many decades, as reviewed in [7]. However, as therein concluded, the increase in power is "not significant enough to offset the associated costs". Moreover, this background art does not teach how to combine CWAT with wave energy conversion, on a breakwater. Disclosure of the invention

The subject matter is electricity generation from wind and wave energies on a breakwater developed in [1]. The breakwater-wave energy conversion was considered in [2]. Here wind energy conversion on such embodiment is described.

The capacity H x Q of the BWEC [2], where H is the head and Q the discharge quantity of water per second, will now be enhanced using the kinetic energy of the wind. The method is illustrated with the help of Fig. 1, depicting the vertical cross section through the middle of the breakwater with incoming wave from the right. The numbers 1 - 11 denote an embodiment of the BWEC: 1 semi-cylinder, 2 small cylinder, 3 and 4 fixing and floating provisions, 5 upper and lower covers of the breakwater wave dissipation openings, 6 one-way inlet valve, 7 conductor, 8 collector, 9 penstock, 10 turbine- generator, 11 tail water returned to the ocean.

Enhanced capacity of the BWEC is achieved by the modifications 12 - 20, Fig. 2 a: side view, b: front view, where 12 is a wind funnel with wind fane and opening as high as the BWEC above water level and of the same width as the BWEC, collecting the wind of given speed over the area (height x width), with speed-adjustment 13, concentrating it into the funnel shaft 14. The speed adjustment adjusts the catch area such that for a given wind speed the resulting wind in 14 has the governing speed of the wind turbine 15, of the Savonius type [8], for optimum efficiency of its load, instead of 13.2% in [3], a gain of factor 7.6, and to prevent overturning of 15, including wind brake and shut off, without the need for a frictional brake system. The housing 16 of the turbine bends the incoming wind to follow the rotation of the turbine and to exit the outlet 17 in the vertical direction to be blown away by the surrounding winds causing chimney draft. Heating the wind in 17 causes the thermal effect of hot air. The arrangement accelerates the wind to blow only on the blade rotating in the wind direction and not frontally on the counter rotating part, the hatched area shades the blade from the side and directs the wind to the tips of the blades for more torque, a gain of factor a = 1/C, C is the power coefficient, 0.1 < C < 0.5 [8]. For semicircular blades C = 0.11, a = 9. In the housing 16 the wind bends and follows the blade rotation, Fig. 2, for more work compared to straight winds as in normal CWAT. The gain is a factor 1.8 and less drag due to larger Venturi effect by two times wind concentration than CWAT. Drag can also be reduced by one-way valves in the blades [9]. The stability of the turbine is secured by sustaining the axis at both ends. This wind accelerated turbine has a gain factor > 3.6 (16 for semicircular blades) compared to CWAT. It can be improved by using side lobs in 14 to create wind jets, Fig. 2 18 conducted around outside the shaft 17 and injected along the path of the blade tips into the rotating direction of the turbine as turbocharger; the result is called Wind Accelerated Turbo Turbine (WATT).

The power on the wind turbine can now be connected to:

Case 1: 19, water pump (without electromotor, rotatable), in the conductor 7, or:

Case 2: electricity generator, as in normal wind turbine-generator.

Case 1. In this case the WATT 15 drives the water pump 19 which speeds the water flow through the conductor 7 enhancing the capacity of the BWEC. After 15 the wind exits the outlet 17, which is bended upward to be blown away by the upper winds. The casing for the modifications is of the same material as the BWEC, i.e. HDPE (high density polyethylene). The shafts of the WATT 15 and water pump 19 are along a common rotatable axis, connected with a differential 20, including idle to disconnect them, e.g. in case of storm or tsunami when the BWEC is shut down. The water pump 19 is a centrifugal pump, efficiency 90%, with the shaft to be connected to that of the wind turbine and disconnected when necessary. The efficiency of the WATT without the generator is estimated to be 90%. The resulting gain of the WATT is > 22 (99 for semicircular blades), compared to [3], while saving 3 wind turbine-generators.

Case 2. In this case the WATT 15 is connected to a generator as WATT-Generator, that generates electricity with 1 electricity generator (instead of 3), using the full area of 12 (instead of 60%), adjusted by 13 to give the wind the governing speed for maximum efficiency (instead of 22%) against overturning of 15, a gain of factor 7.6. The gain of the WATT is > 27 (123 for semicircular blades), while saving 2 turbine-generators, compared to the method of [3]. In case 2 the pump 19 is with the electromotor, with more motional flexibility between the two embodiments compared to case 1.

Further improvement can be obtained by different configuration of the runner blades. For example see Fig. 3, side view of the turbine as in Fig. 2, inlet shaft 14, turbine 15 depicting a runner with 3 semicircular blades, casing 16, outlet shaft 17, turbojets as dashed arrows 18. By introducing cylinder 21, hollow, concentric with the turbine axis, with ends closed and mounting the (smaller) runner blades on it, the wind is forced to move in a toroidal space between 16 and 21 and the torque on the runner is enhanced. To reduce drag the convex sides of the runners are reshaped as indicated in Fig. 3. For cylinder diameter half the original blade diameter the wind is concentrated twice on the runner compared to the case without the cylinder. Twice the power would increase the (average) wind speed by factor 1.26. The speeded rotation (tangential arrow) results in a greater centrifugal force (radial arrow) for better wind exit through 17, which can be regulated by the speed adjustment 13 and wind jets 18.

An electricity generator 22 can be incorporated inside the hollow cylinder as built-in. The rotor of the generator is attached, with electric insulation, either directly or with a differential to the cylinder, which rotates on bearings around the fixed axis of the stator. This axis is suspended on the casing 16 and can be hollow to pass electricity cables to the outside world and cooling system, without interfering with the turbine. Cooling the rotor can by thermal contact with the cylinder and by one-way inlet from the convex side of the runners to reduce drag and one-way outlet of hot air injected into the concave part of the runner. The resulting heated wind benefits the thermal effect as earlier mentioned, p. 3 line 1.

The detail in joining the modification on the BWEC to maintain the breakwater capabilities [1, 2] is according to normal construction skill. The modification serves as windbreaker for the lee side of the wind [10], protecting the coast side against storm winds; the breakwater protects the coast against sea surge. The combination of the WATT Energy (WE), with or without the generator, with the BWEC will be called WEBWEC.

In situations without tsunami hazards or heavy storms, the breakwater functionality of the BWEC is not necessary. A modification of the BWEC, that still serves to mitigate the power of the waves against coastal erosion, is good enough, done as follows. Beneath the WATT engine, a water version in exactly the same way as the WATT is made, powered by water waves instead of wind waves. The turbine axis can be chosen vertical with straight transmission, or horizontal with right angle transmission to a generator above water, or the built-in version can be used. Short shaft 17 with opening above water level and enough kinetic energy left should facilitate the exit of tail water. The embodiment thus obtained is a water accelerated Turbo Wave Energy Converter (TWEC) and with WE denoted by WETWEC, a combined wind and wave energy converter. TWEC can be used for low flow waters, like tidal currents periodically changing directions, for which a reversible version is suitable, obtained by bending the exit shaft to the back after the first 90° turn, Fig. 2, also suitable for oscillating wave column. A reversible wind version is possible. It is also suitable for oscillating wave column. The weight of the turbine 15 can be made equal to the buoyancy in the fluid, e.g. sea water 1025 kg/m³, HDPE 950 kg/m³ leaving room for adjustment or using hollow blades, hollow cylinder as described. In the latter example the turbine 15 includes the blades, the cylinder 21 and part of the built-in, like the rotor of a generator 22, attached to the cylinder. All such examples fall under buoyancy adapted turbine weight.

WATT engines can run on other gasses and liquids, at different pressures and temperatures, suitable for many applications, without movable part on the outside, in particular the WATT with generator inside is compact, for wind as well as for wave energy conversion.

Brief description of drawings

Fig. 1 depicts the installation of the wind energy modification 12 - 20 on a breakwater - wave energy converter 1 - 11, where the wind energy is used to empty the conductor tube 7 so that the next incoming waves are not blocked by a filled conductor tube.

Fig. 2 depicts the parts of the wind energy modification, Fig. 2a side view in cross section and Fig. 2b in front view. 12 is a funnel and 13 is a wind speed regulator, adjusting the wind speed in the funnel shaft 14 such that the wind turbine 15 gets the governing speed for optimal power load on the wind turbine.

Fig. 3 depicts modifications creating an inner space in the wind turbine for further developments, like incorporating an electric generator, in inverted rotor-stator mode. Best mode of carrying out the invention

The invention is further illustrated with some applications: 1) Enhanced hydro capacity. 2) Recycled tail water hydro. 3) Wind powered hydro. 4) Governed speed wind energy.

1) Enhanced hydro capacity is a solution for the Afobaka hydro in Suriname (beloved country of birth). Built during 1960-64, designed at 200 MW power, it is running at 100 MW, because of lack of water for the lake of 1560 km². Sometimes some of the turbine- generators are shut down, a waste of capacity. A plan from 1990 to conduct water from the Tapanahony river and Jai creek is recently abandoned. There is no tsunami or storm hazard so WETWEC is appropriate. Close to the dam WEBWEC can be used without 10, with available turbine-generators of the hydro otherwise idle. Floating on the lake WETWEC collects wind (velocity v = 5-7 m/s). The wind power P = 0.6 v³ Watt/m². For v = 5.5 m/s, P = 100 Watt/m², so 100 m wide WETWEC with wind collector of 20 m high collects a wind power of 200 kW, so 1 MW power per 1 - 2 km² lake is possible. The wind driven waves will also contribute, but this is not relevant for the discussion. Wind and wave farming with WETWECs floating on the lake, in various HDPE colors like "windflowers" turning their faces to the wind, has a capacity of 750 - 1500 MW, a considerable potential, without touching existing structures or changing the environment. Generated electricity can be distributed through the grid of the hydro.

2) Recycled tail water hydro. This is necessary where water is limited and wind speeds are low. Recycling the tail water according to case 1 sustains operation.

3) Wind powered hydro. In regions with low winds and no water, wind can be concentrated to pump up water from an initial reservoir to a collector to run a hydro, with the tail water connected to the initial reservoir, thus maintaining operation.

4) Governed speed wind energy. As in example 3, governed speed wind energy with the WATT-Generator can be applied.

The wind turbines are out of sight. Embodiments are typically 5 - 20 m high, but they can be mounted at elevation for strong winds. Transparent materials can be used when desired. In fluid pathways curves must be smooth (not detailed in the figures) for smooth flow according to Fluid Dynamics. A safety rack in the inlet shaft prevents living beings and trash to be sucked into the turbine, in accidental cases acting like a revolving door, while the centrifugal force helps to push them out. Note in view of the literature search and written opinion of the patent office. Apart from this note no change is made to the text, figures and abstract of the application.

With respect to Dl, when a water wave enters the breakwater-wave energy converter (BWEC) the conductor tube 7 in Fig. 1 is filled with water (having the potential energy of that column of water) and remains so, thus blocking (to that extent of energy) the next incoming waves, a drawback of the BWEC which it cannot solve on its own. Therefore the wind energy addition as described in the application, by driving a centrifugal pump to empty the said conductor, solves that problem for the BWEC. So the application is an essential step beyond prior art Dl.

With regard to D2, which is an invention dealing with induced wind power by barometric and temperature differences between top and bottom of the chimney and/or by wind passing over the top of the chimney, it should be noted that in the present application the chimney draught is simply used as a long known effect, used in solar updraft towers of up to 1 km high and tens of meters in diameter.

In D2 p. 2 lines 85-92 it is mentioned that for a chimney of 24 m high there is no effect measured from barometric and temperature differences, so the invention does not work for such dimensions of chimneys, which is to be expected from meteorological data as well as from the above dimensions of updraft towers, but D2 does not mention at what height the effect will occur. It mentions, p. 2 lines 94-100, that when there is a wind speed of at least 1 m/s, a rising current is produced in the chimney which, on average, is 2.5 m/s, but fails to mention the induced wind speed at the rotor 10, as this is the speed that matters for the power consideration, see e.g. this application p. 6 line 12. It is concluded that D2 is of no help at all, i.e. not a prior art for this application.

The practical, but important aspect of this invention is described on p. 2. lines 25-30, in particular the wind speed regulator 13, which allows that for any location, with a certain variability of wind speeds known from meteorological data, a dedicated wind energy turbine can be constructed suitable for a chosen generator capacity to run at the governing speed, particularly important for places with low winds. The same holds for the application in water, like in low tidal streams, where its reversible version is handy as no change needs be made when the tidal stream changes direction.

Dl: NL 1040 193 C (EMID SOEMAR) 20 January 2014, ref. [2] in the application.

D2: GB 2 055 980 A (PRETINI GISBERTO) 11 March 1981. References

[1] S. Emid, Breakwaters against tsunami and storms, NL patent 1039528, 31.01.2013.

[2] S. Emid, Breakwater as wave energy converter, NL patent 1040193, 20.01.2014.

[3] Floating Power Plant A/S, www.floatingpowerplant.com

[4] Lorc.dk, When floating structures combine wind and wave, 08.07.2011 www.lorc.dk

[5] M. Kanellos, Power plant for wind and waves, 26.04.2010 www.greentechmedia.com

[6] Gaia Wind 133 - 11 kW - Better Generation, www.bettergeneration.co.uk

[7] www.en.wikipedia.org/wiki/compact wind acceleration turbine

[8] B. Deb et al., Journal of Urban and Environmental Engineering 7 (2013) 126 -133.

[9] M. J. Rajkumar and U. K. Saha, Wind Engineering 30 (2006) 243 - 254.

[10] S. Emid, Stormbreakers on habitable spaces, NL patent 1040026, 14.01.2014.

Claims

1. Installation of wind energy combined with breakwater - wave energy converter, with a breakwater, a funnel-shaped wind collector placed on the breakwater, a wind speed regulator, serving also as wind-brake and shut down of the installation, a funnel shaft, a Savonius type wind turbine placed in appropriate housing, with the horizontal axis supported at both ends, characterized by setting the wind speed regulator such that the wind is guided through the funnel shaft at the governing speed for optimum power capacity of the power load connected to the wind turbine, the wind thereby blows on the blades rotating with the wind direction and does not frontally blows on the blades rotating against the wind direction, the out flowing wind through the funnel shaft blows up vertically, carried away by the outside blowing wind stimulating chimney draught, or the wind in the funnel shaft is heated, causing thermal draft.

2. Installation according to claim 1, characterized by injecting through the wind turbine housing concentrated wind-jets along the path of the tips of the blades in the direction of rotation of the blades, to accelerate the rotation of the blades with this technique, named Wind Accelerated Turbo Turbine (WATT).

3. Installation according to claims 1 and 2, in which the energy of the wind turbine is used: 1) to pump away the water, that fills the conduction tube of the wave energy converter and so hinders the inflow of the next incoming waves, up to the collector tank, or 2) to a power generator which in turn operates the pump as in 1), without the need for a friction based braking system for the wind turbine or the generator against too high wind speeds.

4. Water Turbine as the wind turbine according to claims 1 and 2, driven by water waves instead of wind waves, with water outlet just above the water surface.

5. Water turbine according to claim 4, with weight equal to the buoyancy of the turbine, in order that there is minimal friction at the points of support of the ends of the turbine shaft, and that there is little power needed to rotate the water turbine.

6. A wind or water turbine as in claims 1, 2, 4 and 5, which is reversible in such a way, that when the flow direction of the wind or water changes by 180-degrees, nothing needs to be changed to the turbine.

7. A wind or water turbine as in claims 1, 2, 4 and 5, of which the blades are mounted on a hollow cylinder, closed at both ends, concentric with the axis of the turbine, thus concentrating the fluid in the space between the housing and the cylinder near the tips of the turbine blades, thereby generating a higher power output.

8. A wind or water turbine according to claim 7, wherein an electricity generator is incorporated in the hollow cylinder and coupled to it.

9. Turbine according to claim 8, wherein the generator is cooled by the driving fluid, so that the heated fluid is discharged by thermal draft through the exhaust shaft.