Recirculating hydropower system

Abstract

The present invention provides a system for generating electricity comprising a drum having an inlet and an outlet, a lower frustro-conical portion, and preferably an upper frustro-conical portion; a pump in operative connection with the inlet for supplying a fluid to the drum at a desired velocity; and a turbine located within the drum adjacent the outlet, and in operative connection to a generator; wherein the fluid supplied by the pump to the drum is subjected to centrifugal force before passing through the outlet and returning to the pump.

Description

RECIRCULATING HYDROPOWER SYSTEMFIELD OF INVENTION

[0001] The present invention relates to the field of hydropower.

[0002] In one form, the invention relates to recirculating hydropower systems.

[0003] In one particular aspect the present invention is suitable for use for small scale supply of electricity to one or more buildings. In another aspect the present invention is suitable for supplying electricity to an electrical grid.

[0004] It will be convenient to hereinafter describe the invention in relation to micro hydropower systems (5 to 100 kW), however it should be appreciated that the present invention is not limited to that size only.BACKGROUND ART

[0005] It is to be appreciated that any discussion of documents, devices, acts or knowledge in this specification is included to explain the context of the present invention. Further, the discussion throughout this specification comes about due to the realisation of the inventor and / or the identification of certain related art problems by the inventor. Moreover, any discussion of material such as documents, devices, acts or knowledge in this specification is included to explain the context of the invention in terms of the inventor’s knowledge and experience and, accordingly, any such discussion should not be taken as an admission that any of the material forms part of the prior art base or the common general knowledge in the relevant art in Australia, or elsewhere, on or before the priority date of the disclosure and claims herein.

[0006] Hydropower, also called hydroelectricity, uses a flow of water to generate electrical energy. In the past, the flow of water has typically been provided by an upstream source such as a dam or river flowing through a turbine-generator to produceelectricity, and into a downstream river. Hydropower facilities range in size and can be very large, and associated with large volume natural waterways, or very small, taking advantage of low volume flow in municipal water facilities or irrigation ditches.

[0007] Hydropower of the prior art typically relies upon a difference in elevation between the source of water flowing into a turbine-generator (from a dam or diversion structure) and the water flowing out from the turbine-generator.

[0008] Hydropower is considered a very clean form of energy. It does not rely on fossil fuel and does not emit pollutive gases into the atmosphere. However, it is not without its drawbacks. Systems for large scale generation of electricity are limited to sites where natural waterways flow and as such, requires constant, dependable rainfall or other water source. The associated large scale hydro-electric installations require large natural waterways or large dams which may be located distant from the towns or cities where the power is needed. Transmission lines transmit power from a hydroelectric installation to substations, and then to distribution networks within a city but this type of infrastructure is expensive and is also a source of power dissipation. Furthermore, it is expensive and logistically complex to build hydro-electric installations and the routes for overhead transmission lines and support towers. If a dam is required for the upstream water source, this can be technically difficult, expensive and time consuming to build and maintain. Hydroelectric installations and dams can also have a considerable environmental impact.

[0009] Small hydropower installations are typically used in isolated areas that are difficult to access, or uneconomic to supply from a national energy grid, or in areas that have little or no hydroelectricity potential for larger installations.

[0010] Small hydropower systems are typically less than 50 MW, although mini hydropower (<1MW), micro hydropower (<100 kW) and pico hydropower (<10 kW) systems are also used. However, even small scale micro-hydropower installations that operate on a small waterway can have environmental impacts and can damage local ecosystems. Furthermore, small streams often barely provide enough force to generate power, particularly in summer months, and energy expansion is not possible.

[0011] As a result of these drawbacks there has been a growing interest in recirculating hydropower systems, that is, hydropower systems that continually recirculate a controlled volume of water. For example, international patent application WO 2006 / 085782 (PCT / PH2005 / 000015) describes a closed loop hydropower system having powerful jets of water that are released directly from a main penstock (the conduit supplying the turbines) immediately after being subjected to a high water hammer pressure. A series of water pipes draw water directly from a reservoir into the main penstock during a high vacuum phase, after the expulsion of a huge volume of water from the main penstock. The invention is based on using water hammer (excess pressure above the normal hydraulic grade line pressure) caused by the sudden change of water flow velocity in a closed pipeline.

[0012] However, this type of system has the disadvantage of requiring long water pipes that are sufficiently elevated at one end to build up a sufficiently high water hammer.

[0013] United States patent publication no. 2003 / 0127860 describes another type of closed loop hydropower system in which gas is injected into a liquid to produce a flow of water down a guide chute onto a turbine. Specifically, the invention comprises a reservoir and at least one confinement column that is open to the reservoir at its base. A compressor delivers air to an air diffuser at the base of the column to cause water to exit the top of the column and be directed onto a turbine connected to a generator.

[0014] Agbanlog & Chen (Proc.2014 Industrial and Systems Engineering Research Conference) describe a mini-hydropower system that recirculates water from a tank. The system includes a turbine, and a hydraulic ram pump to initiate water circulation together with a modified Heron siphon / fountain. Heron’s fountain uses a flow of water from high gravitational potential energy to low gravitational potential energy, causing a fountain to form due to increasing pressure on the inside of the system.

[0015] Hidayat etal (Materials Sci. and Eng., Vol. 732, The 1stAnnual Technology, Applied Science and Engineering Conference 29-30 August 2019, Indonesia) describes a 5 kW pico hydropower plant weighing only 22kg that uses river passing through a spiral intake designed to produce a spiral vortex to drive a turbine. The spiral vortex can produce faster turbine rotation, compared with a conventional water intake. The turbine is coupled with a generator to produce electricity, through a pulley system. The faster the turbine rotation, the higher the generator output voltage. The highest output voltage of the generator is 27.5 Vdc at the speed of 293 rpm.SUMMARY OF INVENTION

[0016] An object of the present invention is to provide a hydropower system that recirculates water without continuous input of energy from external sources.

[0017] A further object of the present invention is to alleviate at least one disadvantage associated with the related art.

[0018] It is an object of the embodiments described herein to overcome or alleviate at least one of the above noted drawbacks of related art systems or to at least provide a useful alternative to related art systems.

[0019] In a first aspect of embodiments described herein there is provided a hydropower device comprising:• a drum having a fluid inlet and a fluid outlet;• a pump in operative connection with the inlet for supplying the fluid to the drum at a desired velocity; and• a turbine located within the drum and in operative connection to an electricity generator;wherein the fluid is recirculated through the pump, drum and turbine as the generator generates electricity.

[0020] In another aspect of embodiments described herein there is provided a device for generating electricity comprising:• a drum having an inlet and an outlet, a lower frustro-conical portion and preferably an upper frustro-conical portion;• a pump in operative connection with the inlet for supplying a fluid to the drum at a desired velocity; and• a turbine located within the drum adjacent the outlet, and in operative connection to a generator;wherein the fluid supplied by the pump to the drum is subjected to centrifugal force before passing through the outlet and returning to the pump.

[0021] The hydropower system may further comprise an electrical charge storage device such as a rechargeable battery, storage battery or an energy accumulator which can be charged, discharged into a load and recharged many times. Energy from the generator typically passes to the storage device which is used for load-leveling, storing electric energy at times of low demand from the pump, for use during peak periods of system operation. A charger controller may be used to charge and maintains the batteries at a high state of charge without overcharging.

[0022] Fluid such as water is introduced to the drum through the inlet and caused to circulate at high velocity in the drum. Without wishing to be bound by theory it is postulated that centripetal and centrifugal forces are important to flow of water in the drum. Centripetal and centrifugal forces are two terms used to describe the forces associated with circular motion. Centripetal force keeps an object moving in a circular trajectory and the force always acts continuously in the direction of the centre of curvature of the circle. Centrifugal force is a fictions force - an apparent outward force on an object that is moving in a circle. The two rotational forces are the same force, in opposite directions because they are experienced from different frames of reference.

[0023] Again, without wishing to be bound by theory it is postulated that centripetal force causes the liquid to rise in the direction of the force, perpendicular to the inner surface of the frustro-conical portions. To counter the force causing the water to rise, the inner surface of the opposite frustro-conical portion must counter this force. In this state, only centripetal force and gravity act on the fluid circulating at velocity.

[0024] Typically, the turbine comprises multiple blades mounted on the rotor shaft of the generator. The turbine is located within the drum in a position to maximise its revolutions per minute (rpm) but it is also important that the velocity of the water circulating in the drum has a velocity that is sufficient to cause the turbine to rotate. Typically, the turbine blades are located adjacent the outlet and the minor diameter of the drum. Typically, the top edge of the turbine blades are located at the minor diameter of the drum. Where used herein the term ‘major diameter’ is the largest diameter of the lower frustro-conical portion and the ‘minor diameter’ is half the major diameter.

[0025] Each blade of the turbine is typically elongate face that is perpendicular to the centripetal force acting on the circulating water. The tip of the blade is typically configured to closely match the angle of the adjacent inner surface of the lower frustro-conical portion.

[0026] Power generated by the device or the system of the present invention may be used for domestic, commercial or industrial use. For example it may be used to provide power to a home, or a temporary home such as a caravan. Power generated by the device or system of the present invention may also be used for generation of electricity for supply to a grid system or to a storage system such as a battery.

[0027] In another aspect of embodiments described herein there is provided a method of generating electricity using the device of the present invention, comprising:i. operating the pump to pump fluid from a storage tank through the inlet and into the drum at a desired velocity;ii. circulating the fluid around the drum and onto blades on the turbine, causing the rotor shaft of the generator to rotate, generating electricity;iii. passing the fluid through the outlet of the drum to the storage tank; and iv. repeating steps i to iii.

[0028] Preferably the device is controlled remotely by any convenient means well known in the art. In particular the device may be controlled via a laptop or smartphone through an appropriate software app.

[0029] In another aspect of embodiments described herein there is provided a non-transitory computer readable storage medium having a computer program stored therein, wherein the program, when executed by a processor of a computer, causes the computer to execute steps i to iv above.

[0030] In another aspect of embodiments described herein there is provided an application stored on a non-transitory medium adapted to enable a method of generating electricity using the device of the present invention, said application comprising a predetermined instruction set adapted to enable the above method.

[0031] Other aspects and preferred forms are disclosed in the specification and / or defined in the appended claims, forming a part of the description of the invention.

[0032] In essence, embodiments of the present invention stem from the realization that drum design could be used to optimise centrifugal force on circulating water, which concomitantly could optimise rotation of a turbine and generator output. Furthermore, it was realised that optimisation of timing gears and pulleys would provide mechanical advantage.

[0033] Advantages provided by the present invention comprise the following: • generation of electricity;• sustainable;• not reliant on continual supply of energy from external sources;• not reliant on continual supply of water from external sources;• compact size; and• not reliant on alternate energy sources such as wind or sunlight to operate.

[0034] Further scope of applicability of embodiments of the present invention will become apparent from the detailed description given hereinafter. However, it shouldbe understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the disclosure herein will become apparent to those skilled in the art from this detailed description.BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Further disclosure, objects, advantages and aspects of preferred and other embodiments of the present application may be better understood by those skilled in the relevant art by reference to the following description of embodiments taken in conjunction with the accompanying drawings, which are given by way of illustration only, and thus are not limitative of the disclosure herein, and in which:• Figure 1 illustrates large scale hydropower generation of the prior art;• Figure 2 depicts a plan view of a typical system according to the present invention;• Figure 3 depicts one embodiment of a drum according to the present invention viewed from the outside (FIG 3A) and in longitudinal cross-sectional plan view (FIG 3B) and longitudinal cross-sectional perspective view (FIG 3C). FIG 3D is a perspective view of the drum of FIG 3C viewed in the direction Y to -Y;• Figure 4 depicts another embodiment of a drum according to the present invention shown in cross section;• Figure 5 depicts an assembled hydropower system according to the present invention;• Figure 6A depicts a preferred turbine configuration according to the present invention. A single blade (FIG 6B) of the turbine is depicted, with detail of a section of the blade viewed from three different directions (FIG 6C, FIG 6D and FIG 6E).LIST OF PARTS

[0036] Where used in the drawings of aspects and preferred embodiments of the present invention, the reference numbers are intended to refer to the following nonlimiting features:1 Dam 2 Dam wall4 Conduit to turbine 5 Conduit (outlet) to river6 Generator8 Turbine10 Electricity transmission wires 11 Transformer13 Electricity transmission tower 15 River16 Water pump18 Drum20 Generator 21 Charger controller22 Batteries24 Inverter controller26 External AC load 27 Mechanical seal28 Variable speed drive 28 Mechanical seal seat30 Timing belt pulley 31 Protective cover32 Upper frustro-conical portion 33 Lower frustro-conical portion 34 Mid section of drum 35 Bearings36 Water inlet 37 Water outlet38 Turbine blades 39 Turbine hub40 Generator rotor 41 Frame42 Electrical housing44 Timing belt 45 Water storage tank46 Major diameter 47 Minor diameter49 First blade portion50 Second blade portion 51 Third blade portion53 Blade tipDETAILED DESCRIPTION

[0037] For purposes of description herein, the terms “upper,” “lower,” “right,” “left,” “rear,” “front,” “vertical,” “horizontal,” “interior,” “exterior,” and derivatives thereof shallrelate to the invention oriented as indicated by the x, y and z axes where marked. However, it is to be understood that the invention may assume various alternative orientations, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawing, and described in the following specification are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise. Additionally, unless otherwise specified, it is to be understood that discussion of a particular feature of component extending in or along a given direction or the like does not mean that the feature or component follows a straight line or axis in such a direction or that it only extends in such direction or on such a plane without other directional components or deviations, unless otherwise specified.

[0038] FIG 1 illustrates a large scale hydropower system of the prior art that uses a flow of water to generate electricity. In this system water from an upstream source such as a river, dam 1 or diversion structure, flows downhill through a conduit 2 to a penstock then into a powerhouse, past a turbine 8 that powers a generator 6 to produce electricity. The electricity passes to one or more transformers 11 via wires supported by towers 13. The water exits through a conduit 5 into a downstream river 15 or dam.

[0039] This type of arrangement upon a difference in elevation between the source of water (such as a dam, 1 ) and the water outflowing to the lower reservoir or river 15.

[0040] In open loop hydropower systems, the turbine-generator is driven by ongoing hydrologic connection between natural bodies of water. Closed loop systems rely on manmade reservoirs not connected to rivers, lakes or other natural water features. The water exiting the generator into the lower reservoir is pumped back into an upper reservoir that supplies water through a conduit, known as a penstock, to the turbine-generator.

[0041] FIG 2 depicts a plan view of a typical system according to the present invention. Water is pumped from a storage tank (not shown) by a water pump 16 to the drum 18. The drum 18 remains stationary while the water circulates around the inside walls of the drum 18 and pushes a series of turbine blades mounted on a rotor shaft of the generator 20 (not shown). The turbine may be directly coupled to the generator 20, such as by a timing belt pulley 30 (not shown) and timing belt 44 (not shown), to convert the mechanical energy of the turbine to electrical energy.

[0042] The size of the water pump, and the configuration of the drum is important to the system. It is important that the velocity of the water circulating in the drum is sufficient to cause the turbine to rotate. However, if the water pump is too large, it will draw too much current and the water velocity will be too high, causing choking in the drum. If the water pump is too small, then the system will not get the benefit of the centripetal forces within the drum.

[0043] A charger controller 21 regulates current and voltage input from the generator 20. The controller also safely charges and maintains the batteries 22 at a high state of charge without overcharging. If the charger controller 21 does not properly regulate the flow of electricity, this can result in battery failure which causes the entire system to shut down. When there is no external need for AC power and the batteries are at 100% full charge the system remains dormant. If there is a demand for external AC power, the system will start the water pump to supplement the batteries.

[0044] The system further includes an inverter controller 24 to convert the direct current (DC) produced by the generator into alternating current (AC) that can power household devices.

[0045] Part of the AC produced is passed to a variable speed drive 28 for the water pump 16. Electric current will only flow if there is demand, hence when batteries are almost full, most chargers resort to trickle charging so that they do not overcharge the batteries. To achieve this in the system of the present invention, a variable speed driveis associated with the water pump to regulate the water being pumped, and concomitantly the amount of charge going to the batteries.

[0046] The remaining AC power is received by an external AC load bank 26. A programmable AC load bank may be used in the system for testing and measurement of current, voltage and frequency.

[0047] The variable speed drive 28 controls the speed and torque of the AC motor of the water pump 16 by converting fixed frequency and voltage input to a variable frequency and voltage output. System performance can be greatly improved by controlling speed to precisely match the load.

[0048] It is important that the size and torque of the generator of the present system is appropriate for the size of the drum and the water pump. Configuration of the system according to the present invention starts with consideration of the capacity of the generator and its inherent inefficiency. As an example, a 10.0 kW axial flux permanent magnet synchronous (PMG) generator with 90% efficiency will only produce 9.0 kW of power when running at maximum turbine rpm. It is also necessary to consider resistive torque in the turbine. If the water velocity is not sufficiently strong to overcome the resistive torque and rotate the turbine shaft to start the generator, there cannot be any power generation.

[0049] A hydropower calculator of a type well known in the technology can be used to establish the size of the drum and the size of the water pump required to provide a desired power output opposite known efficiency. Using the example of a 10.0 KW generator with an actual output of 9.0 kW, a water pump of 1.5 kW will provide the desired flow velocity, and the corresponding AC output is 7.5kW.

[0050] FIG 3A depicts one embodiment of a drum 18 according to the present invention viewed from the outside, and suitable for use in the system of FIG 2. The drum comprises an frustro-conical shaped upper portion 32 and a frustro-conical shaped lower portion 33, each comprised of a wall having an inner surface and an outer surface. The two frustro-conical shaped portions (32, 33) are integral with anintermediate circular wall 34 in the mid-section of the drum. The circular wall 34 defines a port that functions as an inlet 36 for fluid from the water pump 16. The top of the frustro-conical upper portion 32 defines a port for receiving the generator rotor and turbine. The bottom of the frustro-conical lower portion 33 defines a port that functions as an outlet 37 for water that has circulated in the drum 18.

[0051] FIG 3B depicts the drum 18 of FIG 3A in cross-sectional plan view. Without wishing to be bound by theory, when fluid such as water is introduced to the drum 18 through the inlet 36 and caused to circulate at high velocity around the inner surfaces of the drum 18 the centripetal force keeps the water moving in a circular trajectory. The centripetal force always acts continuously in the direction of the centre of curvature of the circle.

[0052] Again, without wishing to be bound by theory, it is postulated that centripetal force causes the liquid to rise in a direction perpendicular to the inner surface of the frustro-conical walls. The drum must therefore be constructed such that the centripetal force (Fc) associated with the upper frustro conical wall will cancel the centripetal force associated with the lower frustro conical wall and vice versa. In this state, only centripetal force and gravity (g) act on the circulating fluid.

[0053] FIG 3B also indicates the position of the major diameter 46, located at the widest diameter of the lower portion 33, and the location of the minor diameter 47 in this embodiment of the drum. The minor diameter 47 is half the major diameter 46.

[0054] (FIG 3A) and in longitudinal cross-sectional plan view (FIG 3B) and FIG 3C is a longitudinal cross-sectional perspective view of the drum of FIG 3A viewed in the direction Y to -Y. FIG 3D is a perspective view of the drum of FIG 3C viewed in the direction Y to -Y.

[0055] FIG 4 depicts another embodiment of a drum according to the present invention shown in cross section. In this view it is possible to see the turbine blades 38 adjacent the outlet 37 of the drum. The turbine blades 38 are evenly spaced around the circumference of the lower end of the generator rotor 40, the other end of theturbine shaft 30 supporting a timing belt pulley 30. In use, a timing belt is located around the timing belt pulley 30 and a pulley associated with the generator 20.

[0056] FIG 5 depicts a device according to the present invention. The device in this drawing may have a small footprint, for example, approximately 1.6 x 1.4 x 2.5 metres and a generator capacity of 10 kW.

[0057] FIG 6 depicts a turbine according to the present invention. In the embodiment depicted, the turbine comprises at eight blades 38 arranged radially around a hub 39 and a longitudinal axis corresponding to the rotor shaft of the generator.

[0058] The turbine is located within the drum in a position to maximise its revolutions per minute (rpm) but it is also important that the velocity of the water circulating in the drum has a velocity that is sufficient to cause the turbine to rotate. Typically, the turbine blades are located adjacent the outlet, the top edge of the turbine blades being located at the minor diameter of the drum. Where used herein the term ‘major diameter’ is the largest diameter of the lower frustro-conical portion and the ‘minor diameter’ is half the major diameter.

[0059] FIG 6B depicts a single blade of the turbine of FIG 6A, with detail of a section of the blade 38 viewed from three different directions (FIG 6C, FIG 6D and FIG 6E).Each blade 38 of the turbine typically has an elongate face, part of which is perpendicular to the flow of water and the forces that act to make the water flow. FIG 6B indicates that the blade 38 has a first portion 49, a second portion 50 and a third portion 51 which are integral.

[0060] FIG 6C shows a cross section of the blade 38 of FIG 6B viewed in the direction from -X to X. In this view the relative angles of the three portions (49, 50 and 51) can be seen. FIG 6E is a perspective view of the section shown in FIG 6C.

[0061] FIG 6D depicts the tip of the blade 38 which is located adjacent the inner surface of the lower frustro-conical portion of the drum. The angle or shape of the tip53 is configured to closely match the angle of the inner surface of the lower frustro-conical portion to which it is adjacent.EXAMPLE

[0062] The device of the present invention as depicted in FIG 5 was trialled using a single 2.0 kW axial flux generator. Using a hydropower calculator and basing calculations on the torque curve provided by the manufacturer of the generator, a 1 ,300 W water pump was chosen.

[0063] Calculations Based on 2.0 kW Hydro GeneratorGENERATOR TYPE AXIAL FLUX GENERATOR SIZE 2.0 KW EFFICIENCY 95% 1900 WATTS RATED TORQUE 36.1 NM WATER PUMP CAPACITY 1300 WATTS INLET PIPE INSIDE DIAMETER 37MM FLOW RATE 300 LPM MAJOR DIAMETER OF DRUM 600MM MINOR DIAMETER OF DRUM 300MM CIRCUMFERENCE OF MAJOR DIAMETER OF DRUM 1.88 METRES CIRCUMFERENCE OF MINOR DIAMETER OF DRUM 0.942 METRES RPM OF TURBINE SHAFT 259 RPM RPM OF GENERATOR SHAFT 400 RPM PULLEY ON TURBINE SHAFT 254MM PULLEY ON GENERATOR SHAFT 127MM PULLEY RATIO I TO 2 TORQUE AT 400 RPM 29 NM WITH A 1 TO 2 PULLEY RATIO THE TORQUE AT THE TURBINESHAFT 58 NM CALCULATED ENERGY PRODUCED BY THE CENTRIFUGE T=W*9.5 / RPMW=T / 9.5*RPMWATTS 1581.26

[0064] This system generated 1 ,700 Watts of power from the 2.0 kW generator. This was partly due to the turbine achieving only 400 rpm rather than the desired 500 rpm.

[0065] During operation, the water pump exceeded specifications at 500 W, which is almost three times the manufacturer specified wattage. By reducing the power drawn by the water pump, optimising water flow rate and drum design, a higher power output is anticipated.

[0066] While this invention has been described in connection with specific embodiments thereof, it will be understood that it is capable of further modification(s). This application is intended to cover any variations uses or adaptations of the invention following in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains and as may be applied to the essential features hereinbefore set forth.

[0067] As the present invention may be embodied in several forms without departing from the spirit of the essential characteristics of the invention, it should be understood that the above described embodiments are not to limit the present invention unless otherwise specified, but rather should be construed broadly within the spirit and scope of the invention as defined in the appended claims. The described embodiments are to be considered in all respects as illustrative only and not restrictive.

[0068] Various modifications and equivalent arrangements are intended to be included within the spirit and scope of the invention and appended claims. Therefore, the specific embodiments are to be understood to be illustrative of the many ways in which the principles of the present invention may be practiced. In the following claims, means-plus-function clauses are intended to cover structures as performing the defined function and not only structural equivalents, but also equivalent structures.

[0069] Whenever a range is given in the specification, for example, a temperature range, a time range, or a composition or concentration range, all intermediate ranges and subranges, as well as all individual values included in the ranges given are intended to be included in the disclosure. It will be understood that any subranges or individual values in a range or subrange that are included in the description herein can be excluded from the claims herein.

[0070] As used herein, "comprising" is synonymous with "including," "containing," or "characterized by," and is inclusive or open-ended and does not exclude additional, unrecited elements or method steps. As used herein, "consisting of” excludes any element, step, or ingredient not specified in the claim element. As used herein, "consisting essentially of” does not exclude materials or steps that do not materially affect the basic and novel characteristics of the claim. The broad term "comprising" is intended to encompass the narrower "consisting essentially of” and the even narrower "consisting of". Thus, in any recitation herein of a phrase "comprising one or more claim element" (e.g., "comprising A”), the phrase is intended to encompass the narrower, for example, "consisting essentially of A" and "consisting of A". Thus, the broader word "comprising" is intended to provide specific support in each use herein for either "consisting essentially of” or "consisting of". The invention illustratively described herein suitably may be practiced in the absence of any element or elements, limitation or limitations which is not specifically disclosed herein.

[0071] One of ordinary skill in the art will appreciate that materials and methods, other than those specifically exemplified can be employed in the practice of the invention without resort to undue experimentation. All art-known functional equivalents, of any such materials and methods are intended to be included in this invention. The terms and expressions which have been employed are used as terms of description and not of limitation, and there is no intention that in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed. Thus, it should be understood that although the present invention has been specifically disclosed by examples, preferred embodiments and optional features, modification and variation of the concepts herein disclosed may be resorted to by those skilled in the art, and that such modifications and variations are considered to be within the scope of this invention as defined by the appended claims.

[0072] Each reference cited herein is incorporated by reference herein in their entirety. Such references may provide sources of materials; alternative materials, details of methods, as well as additional uses of the invention.

Claims

CLAIMS1. A system for generating electricity comprising:• a drum having an inlet and an outlet, a lower frustro-conical portion, and preferably an upper frustro-conical portion;• a pump in operative connection with the inlet for supplying a fluid to the drum at a desired velocity; and• a turbine located within the drum adjacent the outlet, and in operative connection to a generator;wherein the fluid supplied by the pump to the drum is subjected to centrifugal force before passing through the outlet and returning to the pump.

2. A system according to claim 1 further comprising an electrical charge storage device and a charger controller.

3. A system according to either one of the preceding claims wherein the turbine includes blades located adjacent the outlet and a minor diameter of the drum.

4. A system according to claim 1 wherein the turbine includes blades located adjacent the outlet and a minor diameter of the drum, wherein each blade has an elongate face that is perpendicular to centripetal force acting on the circulating fluid, and a tip of each blade is configured to closely match the angle of an adjacent inner surface of the lower frustro-conical portion.

5. A system according to claim 1 when used to generate electricity for domestic, commercial or industrial use,6. A system according to claim 1 when used to supply electricity to a grid or to a storage system.

7. A hydropower device comprising:• a drum having an upper frustro-conical portion comprising a fluid inlet, and a lower frustro-conical portion comprising a fluid outlet;• a pump in operative connection with the inlet for supplying a fluid to the drum at a desired velocity; and• a turbine located within the drum and in operative connection to an electricity generator;wherein the fluid is recirculated through the pump, drum and turbine as the generator generates electricity.

8. A method of generating electricity using the device of claim 7, the method comprising:i. operating the pump to pump fluid from a storage tank through the inlet and into the drum at a desired velocity;ii. circulating the fluid around the drum and onto blades on the turbine, causing the rotor shaft of the generator to rotate, generating electricity; iii. passing the fluid through the outlet of the drum to the storage tank; and iv. repeating steps i to iii.

9. A non-transitory computer readable storage medium having a computer program stored therein, wherein the program, when executed by a processor, causes the computer to execute steps i to iv of claim 8.

10. An application stored on a non-transitory medium adapted to enable a method of generating electricity according to claim 8, said application comprising a predetermined instruction set adapted to enable steps i to iv.

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