NL1040829C2

NL1040829C2 - Wind and wave energy conversion.

Info

Publication number: NL1040829C2
Application number: NL1040829A
Authority: NL
Inventors: Soemar Emid
Original assignee: Soemar Emid
Priority date: 2014-06-02
Filing date: 2014-06-02
Publication date: 2015-06-26
Also published as: WO2015187006A1

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 C/kWh in wave power of 20 kW/m crest; for comparison: hydro 0.04 C/kWh and OscillatingWaveColumn-WEC 0.85 C/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 C/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.

Description 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 HxQ of the BWEC [2], where H is the head and Qthe 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.

Best mode of carrying out the invention

The invention is further illustrated with some applications: 1) Enhanced hydro capacity. 2) Recycled tail water hydro. B) 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.

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.

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.5 line 33. 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.

Claims

1. Wind energy installation combined with a breakwater - wave energy converter, with a breakwater, a funnel-shaped wind collection arranged on the breakwater, a wind speed-dependent collection control that also acts as a wind brake and stop, a funnel shaft, a Savonius placed in a suitable housing type horizontal-axis wind turbine supported at both ends, characterized by adjusting the collection control such that the wind is guided through the funnel shaft at a speed adapted to the wind speed for optimum transfer of the wind power to the power load connected to the wind turbine, which blows wind on the wind turbine blades rotating with the wind and turns with the rotating blades, and does not blow frontally on the blades rotating against the wind direction, blows the outflowing wind through the funnel shaft in the vertical direction and through the wind blowing outside is blown away, which promotes draft , whether the wind in the funnel shaft is heated, resulting in thermal action.

Installation according to claim 1, characterized by injecting concentrated wind rays through the wind turbine housing along the path of the tips of the blades in the direction of rotation of the blades in order to turn the blades on with this technique called Wind Booster Turbo Turbine (WATT) to hunt.

Installation according to claims 1 and 2, wherein the wind power absorbed by the wind turbine is delivered: 1) to a pump in the water conductor tube of the wave energy converter to pump out the water in said tube that impedes the influx of the following waves to the collecting tank, or 2) to an electricity generator which in turn operates the pump in 1), without the need for a friction-based braking system for the wind turbine or the generator against excessive wind speeds.

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 level.

Water turbine according to claim 4, the weight of which is equal to the buoyancy of the turbine, so that there is minimal friction at the points of support of the ends of the turbine axis and little power is required to rotate the water turbine.

Wind or water turbine according to claims 1, 2, 4 and 5, which is reversible in such a way that when changing the direction of flow of the wind or water by 180 degrees nothing has to be changed on the turbine.

Wind or water turbine according to claims 1, 2, 4 and 5, the blades of which are mounted on a hollow cylinder and closed at the ends, concentric with the axis of the turbine, whereby the fluid is concentrated in the space between the housing and the cylinder, thereby achieving a higher power.

A wind or water turbine according to claim 7, wherein an electric generator, in an inverse rotor-stator configuration, is included in the hollow cylinder and is coupled to the cylinder.

9. Turbine according to claim 8, wherein the generator is cooled by the driving fluid used and the fluid thus heated is also removed from the outlet shaft by thermal means.