Solar augmented wind turbine for stable and dispatchable utility scale power generation
View Patent ↗The present invention describes a novel integration between wind and solar thermal renewable energy technologies. An existing wind turbine consisting of a hub and blades is operated by the power generated from a waterless solar thermal system (using high pressure, high temperature air) during periods of low wind availability. The solar thermal system consist of a heliostat field, solar air receiver panels, a thermal energy storage tank and a Pelton wheel assembly system for converting thermal energy of air into kinetic energy of the power shaft of the wind turbine. The thermal energy converting system consists of a plurality of supersonic air nozzles acting as stator, producing supersonic air jets to interact with a rotating Pelton wheel. A thermal storage system provides means for energy dispatchability. The proposed integrated system is capable of generating a stable renewable energy with minimum intermittency.
1. A system for electric power generation from solar and wind energy sources, comprising:
a wind turbine including:
a tower ( 25 ) having a tower top and a tower base mounted on a surface,
a nacelle cover ( 22 ) mounted on the tower top and comprising an electrical generator ( 27 ) and a main shaft ( 21 ) configured to drive the electrical generator ( 27 ),
a hub ( 28 ) arranged at one end of the nacelle cover and mechanically coupled to the electrical generator through the main shaft ( 21 ), and
a plurality of rotor blades ( 29 ) attached to the hub ( 28 ) for rotating thereof, thereby driving the electrical generator ( 27 );
a driving wheel ( 9 ) mechanically coupled to the electrical generator and to the hub ( 28 );
a wheel manifold ( 43 or 30 ) surrounding the driving wheel ( 9 , or 23 );
at least one solar air-receiver panel ( 5 or 6 ) mounted on the tower ( 25 ) and comprising at least one header ( 32 ) and serpentine flow tubes ( 33 ) connected to the header ( 32 ), said at least one header ( 32 ) and said serpentine flow tubes ( 33 ) containing a gas capable to flow therethrough in operation of the system;
a hot air pipe ( 7 ) being in a gas communication with said at least one solar air-receiver panel at one end, and to the wheel manifold ( 43 ) at another end;
a plurality of heliostats ( 1 ) arranged in the vicinity of the tower ( 25 ) configure for receiving solar light and reflecting the solar light to said at least one solar air-receiver panel;
a thermal storage tank ( 3 ) having a tank top and a tank base, and including a hot air inlet ( 40 ) arranged at the tank top and coupled to the hot air pipe ( 7 ), a cold air-inlet ( 42 ) arranged at the tank base and a cold-air outlet ( 41 ) arranged at the tank base, said thermal storage tank ( 3 ) configured for storing thermal energy transferred from at least one solar air-receiver panel by the gas receiving the thermal energy when passing through the serpentine flow tubes ( 33 ) and through said at least one header ( 32 ) and carrying said thermal energy to said thermal storage tank ( 3 ) when passing to the hot air inlet ( 40 );
a four-way valve ( 26 ) coupled to the hot air inlet ( 40 ) and to the hot air pipe ( 7 ), and configured (i) to provide a gas flow from the thermal storage tank ( 3 ) to the wheel manifold ( 43 ), (ii) to provide a gas flow from said at least one solar air-receiver panel ( 5 or 6 ) to the wheel manifold ( 43 ), and (iii) to provide a gas flow from said at least one solar air-receiver panel ( 5 or 6 ) to the thermal storage tank ( 3 );
an air compressor ( 4 ) in one mode of operation being coupled to the cold air-inlet ( 42 ) of thermal storage tank ( 3 ) for providing the compressed gas thereto for heating the gas, and forcing the heated gas from the thermal storage tank ( 3 ) to the wheel manifold ( 43 ) coupled to the thermal storage tank ( 3 ) through the four-way valve ( 26 ) connected the hot air pipe ( 7 ), and in another mode of operation being couple to said at least one air solar panel ( 5 or 6 ) for heating the gas, and forcing the heated gas from said at least one solar air-receiver panel ( 5 or 6 ) to the wheel manifold ( 43 ) through the four-way valve ( 26 ) connected the hot air pipe ( 7 ); and
a fan ( 2 ) coupled to the cold-air outlet ( 41 ) of the thermal storage tank ( 3 ) and to said at least one solar air-receiver panel ( 5 or 6 ), and configured for providing a gas flow circulation therebetween.
2. The system of claim 1 , wherein the wheel manifold ( 43 ) surrounds the driving wheel ( 9 ) and has a plurality of air nozzles ( 14 ) mounted in openings along an inner circumference of the wheel manifold ( 43 ) and facing the wheel ( 9 ).
3. The system of claim 2 , wherein the air nozzles ( 14 ) are oriented such that an impinging force provided by the compressed gas is tangential to the wheel.
4. The system of claim 2 , wherein the driving wheel ( 9 ) is configured as a Pelton wheel.
5. The system of claim 4 , wherein the Pelton wheel includes a plurality of buckets ( 12 ).
6. The system of claim 5 , wherein a tangential velocity of the buckets in operation of the system is half of a velocity of the gas ejected from the air nozzles ( 14 ).
7. The system of claim 2 , wherein the inner circumference of the wheel manifold ( 43 ) includes an exhaust wheel port ( 47 ) configure for release of the gas from the wheel.
8. The system of claim 7 , further comprising a vacuum pump ( 48 ) in gas communication with the compressor ( 4 ) and the exhaust wheel port ( 47 ) of wheel manifold, and configured for providing vacuum condition at the exhaust wheel port ( 47 ).
9. The system of claim 2 , wherein the air nozzles ( 14 ) of the wheel manifold ( 43 ) are supersonic air nozzles.
10. The system of claim 1 wherein the driving wheel ( 9 ) is mechanically coupled to the electrical generator through a front-end shaft ( 39 ) and to the hub ( 28 ) through the main shaft ( 21 ).
11. The system of claim 1 wherein the driving wheel ( 9 ) is mechanically coupled to the electrical generator through a shaft extension ( 18 ) and to the hub ( 28 ) through the main shaft ( 21 ).
12. The system of claim 1 , wherein the wheel manifold is configured as a housing ( 30 ) surrounding the driving wheel ( 23 ) and has a plurality of vanes ( 49 ) arranged on an inner circumference of the housing ( 30 ) and separated by openings in the inner circumference and providing an expansion of the gas through the vanes ( 49 ) and the openings inwardly toward the wheel ( 23 ) for rotating thereof.
13. The system of claim 1 , further comprising a gear reducer system ( 15 ) arranged between the driving wheel ( 9 or 23 ) and the electrical generator ( 27 ) for matching the rotating speed therebetween.
14. The system of claim 13 , wherein the gear reducer system ( 15 ) is mounted at the rear side of the electrical generator ( 27 ) through a shaft extension ( 18 ).
15. The system of claim 1 , further comprising a brake system ( 19 ) arranged inside the nacelle cover ( 22 ) and a brake system front-end shaft ( 39 ) coupling the brake system ( 19 ) to the electrical generator ( 27 ) through a bevel gear reducer system ( 31 ) which in turn also coupled to the driving wheel ( 9 or 23 ).
16. The system of claim 1 , wherein said thermal storage tank ( 3 ) includes a ceramic honey-comb structure including gas channels formed into a ceramic matrix.
17. The system of claim 1 , wherein said thermal storage tank ( 3 ) includes pebbles.
18. The system of claim 1 , wherein the gas used in the system is selected from air, Helium, CO 2 .