WO2021015664A1

WO2021015664A1 - Hydroelectric inflow dam

Info

Publication number: WO2021015664A1
Application number: PCT/SG2019/050358
Authority: WO
Inventors: Teng Choy Lam
Original assignee: Teng Choy Lam
Priority date: 2019-07-23
Filing date: 2019-07-23
Publication date: 2021-01-28

Abstract

The present invention describes a hydroelectric inflow dam (100, 100a-100e) system. Water flowing into the inflow dam (100, 100a-100e) is operable to continuously rotate a turbine (50) and a generator (55) to produce electric power. The water aft of the turbine is discharged into an air chamber (120), in which water is periodically expelled out from the inflow dam by controlling air displacement via an intake port (123), outlet/discharge port (125) and an air supply port (180). The intake port is regulated by an associated valve plate (130, 130a-130d). Preferably, an air release port (170) is provided to allow air inside the air chamber (120) to release when water flows into the air chamber. Power from solar panels and/or wind turbines supplement power to the air compressor; excess electric power during periods of low power demand is used to compress air and store the compressed air in an accumulator (181).

Description

Hydroelectric Inflow Dam

Field of Invention

[001] The present invention relates to a hydroelectric inflow dam system. In particular, the invention relates to a hydroelectric power generating system by channeling hydraulic inflow from a body of water through a hollow inflow dam structure and returning the discharge water back to the body of water. This inflow dam can be implemented by locating the inflow dam in the body of water or at the shoreline of the body of water.

Background

[002] Patent publication WO2011005215, by the same inventor, describes a hydroelectric inflow dam system where water from a body of water is channeled in through an inflow dam and out to a discharge channel located at a lower elevation. Not all bodies of water are suited to discharge water from a high elevation to a low elevation. Moreover, construction of discharge channels by drilling, digging and laying of underground pipes involves massive earth work, huge expenses and may adversely affect the environmental ecology.

[003] It can thus be seen that there exists a need for a new inflow dam structure to convert potential energy stored in a body of water to kinetic energy and electric energy.

Summary

[004] The following presents a simplified summary to provide a basic understanding of the present invention. This summary is not an extensive overview of the present invention, and is not intended to identify key features of the invention. Rather, it is to present some of the inventive concepts of this invention in a generalised form as a prelude to the detailed description that is to follow.

[005] The present invention seeks to provide hydroelectric inflow dams in which hydraulic inflow from a body of water is channeled through hollow inflow dam structures and the discharge water is returned back to the body of water. The discharge water is periodically expelled from the inflow dams by controlled air displacement so that water is allowed to charge continuously into the inflow dam and operation of the turbine is non-interrupted.

[006] In one embodiment, the present invention provides an inflow dam system comprising: an inflow dam structure operable with a turbine, with the inflow dam structure being located in a body of water; an air chamber fixable inside the inflow dam structure and located aft of the turbine, with the air chamber having an intake port and associated valve plate, an outlet/discharge port and an air supply port; and an air supply connectable from an air pump/compressor to the air supply port, with a control valve operable to regulate air supply to the air supply port; such that water is chargeable into the inflow dam structure and kinetic energy of the water flow rotates the turbine to generate electric power and water aft of the turbine flows periodically into the air chamber, and by periodic opening/closing of the intake port, the outlet/discharge port and the air supply port, water inside the air chamber is periodically expelled out of the air chamber so that water chargeable into the inflow dam is continuous and electric power generation is non-interrupted.

[007] Preferably, a valve plate associated with the intake port is configured on an exterior of the air chamber and on an upper face of the air chamber, whilst the outlet/discharge port is configured on a lower face of the air chamber. It is also possible that a valve plate associated with the intake port is configured on an interior of the air chamber and on an upper face of the air chamber. The valve plate is moveable between an open position and a closed position over the intake port, respectively, to allow water flow or to shut off water flow into the air chamber; it is possible that the valve plate is moveable in a rotatable motion or a linear slidable motion, by a linear fluid actuator or a fluid motor.

[008] Preferably, the system further comprises an air release port configured on the upper face of the air chamber, and a float to control the air release port. The float may be equipped with a float switch, which when activated is used to control a solenoid valve disposed at an air release line (linked to the air release port) and to the solenoid valve disposed at the air supply line (linked to the air pump/compressor).

[009] Preferably, the outlet/discharge port is regulated by a one-way valve or a flip valve. [0010] In one embodiment, the intake port and the outlet/discharge port are aligned and associated valve plates are inter-connected by a stem, so that when the intake port is actuated to open, the outlet/discharge port is actuated to close, and vice versa.

[0011] In another embodiment, walls of the air chamber are hollow and valve plates associated with both the intake port and the outlet/discharge port are mechanically linked by a chain or flexible cable and associated sprocket or pulleys. The system may further comprise a spring operable to urge the valve plate associated with the intake port or the outlet/discharge port, or two springs operable on the two valve plates, in counter action with the spring or springs with a remote actuator located at a distal end of the chain or flexible cable.

[0012] In another embodiment, the system further comprises valve plates associated with the intake port and the outlet/discharge port, and a fluid cylinder associated with each of the valve plate is configured with double rods, where the two double-rod fluid cylinders are fluidly inter-connected, so that when one valve plate is moved to an open position, the other valve plate is moved to a closed position, and vice versa.

[0013] Preferably, the inflow dam system is located at or along a shoreline of a body of water. Preferably, solar panels and/or wind turbines generate power to supplement power to the air pump/compressor and during low periods of low power demand, excess electric power is used to compress air and to store energy in an air accumulator, which provides controlled air displacement in the air chamber.

Brief Description of the Drawings

[0014] This invention will be described by way of non- limiting embodiments of the present invention, with reference to the accompanying drawings, in which:

[0015] FIGs. 1A-1B illustrate two types of inflow dam system for two types of water turbine according to the present invention, while FIG. 1C illustrates a variation of the inflow dam structure shown in FIG. IB, and FIGs. 1D-1G illustrate arrangements of valve plates on air chambers located inside the inflow dam structure;

[0016] FIGs. 2A-2B illustrate an inflow dam structure and associated valve plates according to another embodiment;

[0017] FIG. 3 illustrates an inflow dam structure and associated valve plates according to another embodiment;

[0018] FIG. 4 illustrates an inflow dam structure and associated valve plates according to another embodiment;

[0019] FIG. 5 illustrates an inflow dam structure according to another embodiment; and

[0020] FIG. 6A illustrates an inflow dam structure being located at a shoreline of a body of water; FIG. 6B illustrates an implementation of the inflow dam structure using an impulse turbine, whilst FIG. 6C illustrates an implementation with a reaction turbine; FIGs. 6D-6E illustrate a valve gate for use with the inflow dams shown in FIGs. 6B-6C.

Detailed Description

[0021] One or more specific and alternative embodiments of the present invention will now be described with reference to the attached drawings. It shall be apparent to one skilled in the art, however, that this invention may be practised without such specific details. Some of the details may not be described at length so as not to obscure the principles of working of the present invention.

[0022] FIGs. 1A and IB show simplified views of two inflow dams 100 using impulse and reaction turbines according to embodiments of the present invention. As shown, the inflow dams 100 are located in a body of water 20, for eg. being stored behind an embankment 22 and supported by a hollow footing 24; in other drawings, the inflow dams 100 are shown to be located along or near a shoreline of a body of water. The body of water can be in a reservoir, lake, lagoon, river, sea, and so on. In the embodiment shown in FIG. 1A, the inflow dam 100 is built higher than the highest water level but the walls of the inflow dam

100 are formed with nozzles 111 so that jets of water flow from outside the inflow dam 100 into the interior cavity 101; the kinetic energy in the water jets is imparted to the impellers of the turbine 50, thereby rotates the turbine to generate electric power; in one embodiment, the nozzles 111 are controlled by an adjustable sleeve 112 having apertures 114. The turbine 50 is connected to a generator 55 through a drive shaft 52 and, where necessary, a gear system 54 (not shown in the figures). In the embodiment shown in FIG. IB, the inflow dam 100 is located below the highest water level and water flows into the interior cavity

101 over an adjustable weir 115, which is adjustable by actuators 116. In both embodiments, the water downstream of the turbine flows into an air chamber 120, which is periodically charged with air from an air pump or air compressor 60 (shown in later figures) to expel water from the inflow dam structure. In the following description and drawings, the inflow dam structure 110 is highly simplified and illustrates water flowing into the interior cavity 101 without detracting from the principle of charging the inflow dam 100 continuously with water and periodically discharging the water from the interior cavity 101 back into the same body of water 20.

[0023] FIG. 1C shows the inflow dam 100 with water continuously charging into the interior cavity 101, rotating the turbine 50 to generate electric power and periodically being expelled out of the air chamber 120, with the air chamber 120 being located a lower interior portion of the inflow dam 100. The air chamber 120 has an intake port 123, which is being periodically operated to open/close and an outlet (or discharge) port 125 being alternatingly operated in cooperation with the intake port 123; thus, water in the air chamber 120 is being periodically discharged out through the lower interior portion to allow water to charge continuously into the inflow dam so that operation of the turbine 50 is non- interrupted.

[0024] As shown in FIG. 1C, the air chamber 120 is made of a hollow chamber with the intake port 123 being configured on an upper face 122, together with an air release port 170 and an air supply port 180, whilst the outlet (or discharge) port 125 is configured on a lower face 124. In FIG. 1C, the intake port 123 is shown to be controlled by a valve plate 130, whilst the outlet/discharge port 125 is controlled by a one-way valve 150. In one embodiment, the valve plate 130 is configured on an exterior of the upper face 122; in another embodiment, the valve plate 130 is configured on an inside of the upper face 122.

[0025] FIG. ID shows a valve plate 130 being operable with a fluid actuator 133 according to one embodiment. The valve plate 130 is shown simplified and only to illustrate its use; the valve plate 130 has an aperture 131 or a plurality of apertures 131, which become in register with the associated intake port(s) 123 when the valve plate 130 is in an open position, and the aperture(s) 131 are blocked when the valve plate 130 is in a closed position. For illustration, the valve plate 130 is shown with two apertures 131 and two holes as the intake port 123. The valve plate 130 is pivotable about a pivot 132 by the fluid actuator 133.

[0026] To reduce impeded flow of water into the air chamber 120, the air release port 170 is preferably provided on the upper face 122. In one embodiment, the air release port 170 is controlled by a float 173. Preferably, the float 173 is supplied with a float switch 173a (not shown in the figure). In use, when water is allowed to flow into the air chamber 120, air displaced in the air chamber 120 is released through the air release port 170 until the water level in the air chamber 120 reaches a high H level and actuates the float 173 to close; after the float 173 is actuated to close, the float switch 173a is activated, and a signal is sent to the air pump/air compressor 60 to supply air into the air chamber 120 through the air supply port 180 and an air supply line 182; at the same time, another signal is sent to a solenoid valve 172 to close the air release line 171 that is in fluid communication with the air release port 170. In this way, air periodically enters the air chamber 120, displaces water inside the air chamber 120 and expels water out through the outlet/discharge port 125 and one-way valve 150. In another embodiment, it is possible that the signal to control air supply into the air chamber 120 is connected to a control valve (182 shown in other figures) located on the air supply line 182. By sizing capacities of the air chamber 120, the air pump/accumulator 60 and associated air accumulator appropriately, water charging into the inflow dam 100 becomes continuous, and water aft of the turbine 50 fluctuates periodically between high H and low L levels as water is expelled periodically from inside the air chamber 120 by controlled air displacement. With continuous charging of water inside the inflow dam 100, rotation of the turbine 50 is non-interrupted and electric power generation is continuous. [0027] FIG. IE shows a variation of the valve plate 130 shown in FIG. ID. The valve plate in FIG. IE is shown with a plurality of apertures 131; the apertures 131 are indexable to align with associated holes forming the intake port 123, preferably about a pivot 132 by a fluid actuator 133. In FIG. IF, the valve plate 130 is rotatable by turning a ring gear 136 with a pinion 137 connected to a fluid motor 138. In another embodiment, instead of using a complete ring gear 136, two segments of the ring gear may be employed, as the valve plate 130 is reciprocated through an angular movement.

[0028] The valve plate 130 shown in FIG. ID or IE can be configured either on the exterior or interior of the air chamber 120. An advantage of locating the valve plate 130 on the exterior of the air chamber 120 is that when the valve plate 130 is in the closed position, the valve plate is self-sealing as water pressure urges the valve plate 130 onto the upper face 122. FIG. 1G shows a valve plate 130a according to another embodiment. The valve plate 130a is linearly guided by a guide 135 and is shown to be actuatable by a fluid actuator 133a. As in the above embodiment, when the valve plate 130a is at its closed position, the holes of the intake port 123 are blocked, and when the valve plate 130a is in its open position, the apertures 131 on the valve plate 130a allow water to flow into the air chamber 120. In the above embodiments, the valve plate 130 may be made from an engineering polymer, stainless steel, aluminium, or a metal that is dissimilar from material of the air chamber to minimise galvanic corrosion.

[0029] FIG. 2A shows an inflow dam 100a being equipped with an air chamber 120a according to another embodiment. The air chamber 120a is similar to the above air chamber except for arrangement of the intake port and the outlet/discharge port. In FIG. 2A, the intake port 123 and the outlet/discharge port 125 are linearly aligned and the associated valve plates 130b are connected by a stem 141, such that when the intake port 123 is opened, the outlet/discharge port 125 is closed, and vice versa. FIG. 2B shows a plan view of the valve plate 130b. As seen in FIGs. 2A-2B, two holes of each of the intake port and outlet port are shown only for illustration and a fluid actuator 142 is provided to move the valve plates 130b between the open and closed positions. The manner of operating of the valve plates 130b in cooperation with the float 173 and air supply port 180 is similar to that in the above description.

[0030] FIG. 3 shows an inflow dam 100b being equipped with an air chamber 120 according to another embodiment. As shown in FIG. 3, the air chamber 120 also has similar intake port 123, an outlet/discharge port 125, air release port 170 and air supply port 180, but the walls of the air chamber 120 are hollow and valve plates 130c associated with both the intake port 123 and outlet/discharge port 125 are mechanically linked via a chain or flexible cable 151. Sprockets or pulleys 152 are provided to change direction of the chain or flexible cable 151. Each of the valve plates 130c has 3 positions, namely, an open position and 2 close positions. The pair of the valve plates 130c are linked so that when the intake port 123 is open, the outlet/discharge port 125 is closed, and vice versa, and in the transition both the intake and outlet ports are closed. In another embodiment, it is possible that the valve plates 130c are configured with only 2 positions, such that when the intake valve 123 is opened, the outlet/discharge valve 125 is closed, and vice versa. As shown, the intake valve plate 130c is urged by a spring 154 and a distal end 153 of the chain or flexible cable is remotely controlled by an actuator (not shown) operable in counter action with the spring 154; preferably, the actuator at the distal end 153 of the chain or flexible cable 151 is located above the water line. In another embodiment, it is possible that the spring 154 urges on the valve plate 130c associated with the outlet/discharge port 125, or two springs 154 are employed, separately urging on the two separate valve plates 130c.

[0031] In another embodiment shown in FIG. 4, the valve plates associated with the intake port 123 and the outlet/discharge port 125 are actuated by a pair of fluid cylinders 160; the pair of fluid cylinders 160 are configured with double rods and are fluidly interlinked so that when one fluid cylinder extends, the linked fluid cylinder retracts; in this way, the valve plates associated with the intake and outlet ports are moveable in coordination between their open and close positions to allow or shut water flow through them.

[0032] In another embodiment, FIG. 5 shows another inflow dam lOOd. The inflow dam lOOd is a variation of that shown in FIG. 1A. As shown in FIG. 5, water jets flowing through nozzles 111 rotate the turbines 50 and generators 55 to generate electric power; whilst two sets of turbine and generator are shown only for illustration, it is possible that water jets operate on one set or more than two sets of turbine and generator. As in the above description, water aft of the turbine(s) flows periodically into the air chamber 120 and water is periodically expelled out of the air chamber 120 by controlled air displacement. In one embodiment, solar panels 57 are installed above the inflow dam and supply electric power to supplement power generation to provide a positive balance of plant output. In another embodiment, electric power can also be additionally tapped from a wind turbine that may operate near a coastline of such body of water.

[0033] When further controlled air displacement is required, the inflow dam lOOd structure can include an open air chamber 121 located below the air chamber 120. The open air chamber 121 may not require a discharge valve but is provided with an air release port 170 and an air supply port 180. The workings of the air release port and air supply port are similar to the above description.

[0034] FIG. 6A shows a number of the inflow dams lOOe being implemented along a shoreline of a body of water, for eg. along a sea or river, according to yet another embodiment. FIG. 6B shows the use of an impulse turbine, whilst FIG. 6C shows the use of a reaction turbine, but the principles of charging the water aft of the turbine 50 into an air chamber 120 and periodically expelling the water from the air chamber 120 remain unchanged. As shown in FIG. 6A or 6B, adjoining each inflow dam is a sub-station 70 where the outputs of the generators 55 and solar panels 57 (and/or wind turbines) are coupled to the external electric grid. A control room 80 is shown where power generation is regulated according to demand, and excess electric power is used to operate the air compressor 60 and to store the compressed air in an accumulator 181. A control valve 182 is used to periodically control compressed air supply into the air chamber 120 and to periodically displace water from the air chamber through an outlet/discharge valve 125 or a plurality of outlet/discharge valves 125; in one embodiment, each outlet/discharge valve 125 is configured as a flip valve, through which water is discharged out and any water tending to flow in would close the flip valve.

[0035] FIGs. 6D and 6E show the intake ports 123 are controlled by spring-actuated balls 177 and a slidable valve plate 130d. The slidable valve plate 130d is located below the intake ports 123 and is supported on a member 179. The valve plate 130d is made up of an upper plate 174, a lower plate 175 and interconnecting plates 176. The upper and lower plates 174, 175 has holes that are formed at regular pitch distances, so that some spring- actuated balls 177 are located in some respective spaces formed by the plates 174, 175, 176 and the remaining spaces are left vacant for water to flow through the valve plate 130d. When the valve plate 130d is in a closed position, all the intake ports 123 are closed by the spring-actuated balls 177; when the valve plate 130d is displaced to its open position (for eg. by actuating a fluid actuator, motor and gear assembly, etc.,) the intake ports 123 become unblocked, thereby allowing water in the valve chamber 117 to charge into the air chamber 120. In one embodiment, one or more of the spring actuated balls 177 is/are used to control the air release port(s) 170, such that when water is allowed to charge into the air chamber 120, air displaced in the air chamber 120 is allowed to release. As in the above description, the high H and low L water levels in the valve chamber 117 or air chamber 120 can be controlled using a float 173 or float switch 173a.

[0036] It is envisaged that the inflow dam capacity is determined by selection of the turbine 50 and rate of inflow water (which depends on the water head and inlet nozzle opening), the data of which are then used to decide on the air chamber 120 size and air delivery capacity from the air pump/compressor 60 and associated accumulator capacity. These data would then be used to determine the high H and low L water levels, and periodic time interval for controlling the air displacement rate, and iteratively determine the size and length of the inflow dam structure 110.

[0037] FIG. 6A shows the inflow dam lOOe being located along a coastline. In a variation (not shown in the figures), it is possible to locate the inflow dam a short distance (for eg. tens of meters) inland from the coastline, with one water intake pipe channeling water from the body of water 20 to the turbine 50 and another water pipe discharging water from the discharge port 125 back to the body of water. With this variation, it is possible to lower the costs of constructing the inflow dam lOOe along the coastline, or to minimise any adverse environmental impact.

[0038] An advantage of the above inflow dam system 100, 100a- lOOe is that it is scalable, in terms of power capacity, number of units of inflow dams and available funds, etc.; the power generation capacity in turn depends on demand for electric power. For eg., when there is higher electric power demand, more inflow dams can be added even after some initial installations. Some of the inflow dams can be closed by regulating the intake sleeves or weirs, for eg. for preventive maintenance or during periods when electric power demand is low. Advantageously, when the inflow dams are located near the water shoreline (be it a river, lake, sea, etc.), some of the equipment, such as, the air pump/compressors and system controllers (not shown in the figures) can be located on land; in addition, there is no need to lay submarine cables or long submarine cables to the shore. It is believed that the costs of providing these inflow dam systems are comparatively lower than conventional hydroelectric dam systems. It is also possible to supply the inflow dam system from a micro system of a few kW, a mini- system of a few hundred kW to a large-scale system of several MW capacities, which conventional hydroelectric dam system is not scalable.

[0039] While specific embodiments have been described and illustrated, it is understood that many changes, modifications, variations and combinations thereof could be made to the present invention without departing from the scope of the present invention. For example, the air release pipe and air supply lines may be routed to the outside of the inflow dam structure, as shown in FIG. 5.

Claims

CLAIMS:

1. An inflow dam system comprising:

an inflow dam structure operable with a turbine, with the inflow dam structure being located in a body of water;

an air chamber fixable inside the inflow dam structure and located aft of the turbine, with the air chamber having an intake port and associated valve plate, an outlet/discharge port and an air supply port; and

an air supply connectable from an air pump/compressor to the air supply port, with a control valve operable to regulate air supply to the air supply port;

such that water is chargeable into the inflow dam structure and kinetic energy of the water flow rotates the turbine to generate electric power and water aft of the turbine flows periodically into the air chamber, and by periodic opening/closing of the intake port, the outlet/discharge port and the air supply port, water inside the air chamber is periodically expelled out of the air chamber so that water chargeable into the inflow dam is continuous and electric power generation is non-interrupted.

2. The inflow dam system according to claim 1, wherein a valve plate associated with the intake port is configured on an exterior of the air chamber and on an upper face of the air chamber, whilst the outlet/discharge port is configured on a lower face of the air chamber.

3. The inflow dam system according to claim 1, wherein a valve plate associated with the intake port is configured on an interior of the air chamber and on an upper face of the air chamber.

4. The inflow dam system according to claim 2 or 3, wherein the valve plate is moveable between an open position and a closed position over the intake port, respectively, to allow water flow or to shut off water flow into the air chamber.

5. The inflow dam system according to claim 4, wherein the valve plate is moveable in a rotatable motion or a linear slidable motion.

6. The inflow dam system according to any one of claims 2-5, further comprising an air release port configured on the upper face of the air chamber, and a float to control the air release port.

7. The inflow dam system according to claim 6, wherein the float is equipped with a float switch, which when activated is used to control a solenoid valve disposed at an air release line (linked to the air release port) and to the solenoid valve disposed at the air supply line (linked to the air pump/compressor).

8. The inflow dam system according to any one of the preceding claims, wherein the outlet/discharge port is regulated by a one-way valve or a flip valve.

9. The inflow dam system according to claim 1, wherein the intake port and the outlet/discharge port are aligned and associated valve plates are inter-connected by a stem, so that when the intake port is actuated to open, the outlet/discharge port is actuated to close, and vice versa.

10. The inflow dam system according to any one of claims 2-9, wherein the valve plate or valve plates are operable by a linear fluid actuator or a fluid motor.

11. The inflow dam system according to claim 1, wherein walls of the air chamber are hollow and valve plates associated with both the intake port and the outlet/discharge port are mechanically linked by a chain or flexible cable and associated sprocket or pulleys.

12. The inflow dam system according to claim 11, further comprising a spring operable to urge the valve plate associated with the intake port or the outlet/discharge port, or two springs operable on the two valve plates, in counter action with the spring or springs with a remote actuator located at a distal end of the chain or flexible cable.

13. The inflow dam system according to claim 1, further comprising valve plates associated with the intake port and the outlet/discharge port, and a fluid cylinder associated with each of the valve plate is configured with double rods, where the two double-rod fluid cylinders are fluidly inter-connected, so that when one valve plate is moved to an open position, the other valve plate is moved to a closed position, and vice versa.

14. The inflow dam system according to claim 1, wherein the inflow dams are located along a shoreline of a body of water.

15. The inflow dam system according to claim 1, wherein solar panels and/or wind turbines generate power to supplement power to the air pump/compressor and during low periods of low power demand, excess electric power is used to compress air and to store energy in an air accumulator, which provides controlled air displacement in the air chamber.