WO2012039629A1

WO2012039629A1 - Pressure differential system extracting energy in various forms including, motion, temperature and pressure

Info

Publication number: WO2012039629A1
Application number: PCT/NZ2011/000167
Authority: WO
Inventors: Phillip James Scandle
Original assignee: Individual
Current assignee: Individual
Priority date: 2010-09-24
Filing date: 2011-08-25
Publication date: 2012-03-29
Anticipated expiration: 2013-03-24

Abstract

A method of generating energy from the flow of material through, into or out of a high pressure sealable main chamber is provided, the method including the steps of: inserting a resilient material into the main chamber and sealing it; locating the inlet of the main chamber at a depth within a body of liquid; setting an inlet flow control device to the open position to enable the liquid to flow into the main chamber thus compressing the resilient material; setting the inlet flow control device to the closed position to enable the resilient material in the main chamber to expand and displace at least some of the liquid in the main chamber out through the outlet; repeating the previous two steps to create a flow of fluid and resilient material through the main chamber; and extracting energy from the flow of the resilient material and/or the liquid.

Description

PRESSURE DIFFERENTIAL SYSTEM EXTRACTING ENERGY IN VARIOUS FORMS INCLUDING, MOTION, TEMPERATURE AND PRESSURE

TECHNICAL FIELD The present invention relates to a method and apparatus for extracting energy from a system using the pressure differential between a region of relatively high pressure and a region of relatively low pressure. In particular the invention relates to a method and apparatus where the pressure differential is created by the pressure difference between the top and bottom of a column of liquid, such as (without limitation) water.

BACKGROUND ART

In a world of ever increasing demand for energy and energy sources, many new and innovative techniques are being used to generate energy in various forms (including electricity, motion, temperature and pressure). Ideally such systems use naturally occurring forces and energy sources, such as solar, wind, wave and tidal flow, as these energy sources are generally renewable and relatively predictable in their occurrence. More traditionally, hydro-systems have been used to generate electricity from the flow of water from a high storage place (lake, river etc) to a lower level. In many cases the high storage place has been created artificially by erecting a dam across a river to create a large body of water behind the dam, the level of water being higher than the level of ground below the dam.

In contrast, tidal systems make use of the natural tidal flow of water into and out of a region, by placing a turbine in the tidal flow. The flow of water through the turbine creates the motion which can be harnessed and converted into electricity.

Another natural source of potential energy generation which has been gaining attention lately uses the pressure differential that exists at different heights within a column of liquid. It is well known that the pressure at any depth, D, below the surface of the liquid is given by the product of the density of the liquid, the acceleration due to gravity and the depth, D. Hence, the pressure is directly proportional to the depth below the surface. Such pressure differences may be very large, for example between the surface and bottom of a deep body of water (reservoir, lake, sea or ocean for example).

US Patent Application publication no. US 2010/0084866 A1 (to Smith) discloses a system for generating electricity using a hydro-hydraulic gravitational generator. The system includes a main housing which is located deeply in a body of water. A piston is configured to rise within the housing as water under pressure enters through an inlet valve. Air is purged from the main housing as the piston rises. The flow of water into the housing may be used to drive a water turbine (for example to generate electricity). After the piston has reached its peak position the inlet valve is closed. The main housing is exposed to atmospheric pressure via a pipe connection to above the surface of the water, following which the piston falls under gravity, expelling water from the housing (typically into a second housing which may include a pump to aid purging of excess water from the housing). The expelled water can also flow through a water turbine to generate further energy. Smith discloses that the system may be cycled in this fashion to provide a more or less continuous method of generating electricity from the inflow and outflow of water through the housing

One possible disadvantage of the system disclosed by Smith is that, in common with all piston/piston cylinder systems, there may be considerable problems in maintaining a complete seal around the piston. Such a seal is necessary to prevent leakage of water around the edge an into the chamber above the piston. If this were to happen the system would eventually fail as the chamber would ultimately fill with water. In the meantime, the efficiency of the system would tend to fall off quite rapidly.

Another problem that derives from this arrangement is the need to provide a housing that will maintain its dimensional stability under considerable pressure. If, for example, the housing is to be located on a seabed, it must be able to withstand the external force due to the pressure of the water around it. It is likely to require a high degree of engineering skill to produce a housing that can withstand such pressure and still provide an acceptable seal around a piston configured to move inside the housing.

Further, water (especially sea water or "dirty" water) can be corrosive to many materials, as commonly seen, for example, on the metal hulls and fixtures on ships. Thus the surface of the housing and the piston need to be made of a material able to withstand this corrosion, or at least be coated with a suitable protective layer. Given the large forces at work, the fine tolerances required between the housing wall and the piston and the wear that is likely to occur over time, finding a suitable material is likely to be costly.

Given that the housing is located deep within a body of water access for maintenance is also likely to be limited and costly.

It is an object of the present invention to address the foregoing problems or at least to provide the public with a useful choice.

All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art. The discussion of the references states what their authors assert, and the applicants reserve the right to challenge the accuracy and pertinency of the cited documents. It will be clearly understood that, although a number of prior art publications are referred to herein, this reference does not constitute an admission that any of these documents form part of the common general knowledge in the art, in New Zealand or in any other country. Throughout this specification, the word "comprise", or variations thereof such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only.

DISCLOSURE OF THE INVENTION

According to one aspect of the present invention there is provided a method of generating energy from the flow of material through, into or out of a high pressure sealable main chamber, the main chamber including an inlet with an inlet control device having an open position in which the material can flow into the main chamber and a closed position, and an outlet, the method including the steps of: a) Inserting a resilient material into the main chamber and sealing it; b) locating the inlet of the main chamber at a depth within a body of liquid; c) setting the inlet flow control device to the open position to enable the liquid to flow into the main chamber thus compressing the resilient material; d) setting the inlet flow control device to the closed position to enable the resilient material in the main chamber to expand and displace at least some of the liquid in the main chamber out through the outlet; e) repeating steps c) and d) to create a flow of fluid and resilient material through the main chamber; and f) extracting energy from the flow of the resilient material and/or the liquid through the main chamber, and/or of the liquid into or out of the main chamber.

According to another aspect of the present invention there is provided a method substantially as described above wherein the resilient material is inserted into the main chamber after the inlet to the main chamber is located at a depth within a body of liquid. According to another aspect of the present invention there is provided a method substantially as described above including the step of using a pump to aid removal of the liquid removed from the main chamber in step d).

According to another aspect of the present invention there is provided a method substantially as described above including the step of adding compressed resilient material to the main chamber in step d).

A feature of the present invention is the use of a high pressure, relatively incompressible material, such as a liquid at depth, to compress a much more highly compressible, resilient material within the main chamber. The applicant asserts that by controlling the flow of liquid into the main chamber and out of the main chamber an oscillating movement may be created.

Energy may be generated from this oscillating flow, for example by passing the flow through one or more turbines, by connection to an hydraulic or pneumatic device, or any of the other ways well known to those skilled in the art (alone or in combination).

In a preferred embodiment the liquid is water. Water is preferred as, like air, it is generally available at little or no cost. Further, water may be found in deep columns in many places in nature; for example (without limitation) in lakes, seas and oceans, as well as in many man-made structures (reservoirs, artificially formed lakes behind dams etc). It is also relatively straight forward to form a deep column of water (or other liquid), for example by incorporating a long watertight tube into a tall structure such as a multi- storey building, on a hillside or within a mine shaft, for example.

Those skilled in the art will appreciate that any suitable liquid may be used within the scope of the present invention, and that reference to the liquid being water only throughout this specification should not be seen as limiting.

A resilient material may be any material which is able to regain its original shape or position after bending, stretching, compression, or other deformation. In general a resilient material in accordance with the present invention is one which exhibits a restoring force that resists deformation, such that when the deforming force is removed the material is restored to its original form, shape or position. All elastic materials are resilient, including springs, elasticised bands etc. In a preferred embodiment the resilient material is a gas.

A gas may be readily compressed as the liquid enters the chamber. The pressure of a gas is proportional to the volume of space containing it. As the high pressure liquid enters the chamber the space available to the gas decreases, thus increasing the gas pressure. This pressure may be subsequently used to force liquid out of the chamber, thus increasing the available space for the gas and hence reducing the gas pressure.

Preferably the gas is air.

Air may be preferred as it is readily available at little or no real cost. Use of air is also environmentally acceptable.

Those skilled in the art will appreciate however, that any resilient material may be used

(including any gas), and that reference throughout this specification to resilient material being a gas, and particularly air, should not be seen as limiting.

Preferably the inlet to the main chamber is located at a depth of at least 2 metres below the surface of a body of liquid.

Preferably the base of the main chamber is placed on the bottom of a body of liquid, such as a sea bed or lake bed. Alternatively, the base of the main chamber may be placed on the base of a vertical conduit configured to hold a body of liquid. The advantage of such arrangements is that the main chamber may not require further support. An advantage of placing the inlet of the main chamber at a depth of at least 2 metres below the surface of the body of liquid is that the pressure of the liquid (equal to the product of the density of the liquid, the acceleration due to gravity (g) and the depth below the surface) may provide a significant differential with the atmospheric pressure at the surface of the liquid

In some embodiments the outlet of the main chamber includes an outlet control device having an open position in which the material can flow out of the main chamber and a closed position.

According to another aspect of the present invention there is provided an apparatus for generating energy including: a high pressure sealable main chamber having an inlet located in the vicinity of a base of the main chamber, the inlet including an inlet flow control device having an open position in which liquid can flow into the main chamber and a closed position; and an outlet including an opening located at a position which, in use, is below the level of liquid in the chamber; and at least one energy conversion device configured to extract energy from the flow of liquid into the main chamber, out of the main chamber, or through the main chamber. A main chamber according to the present invention may be of any shape or configuration and may include internal flow control devices to control the flow of material from one section of the chamber to another. For example, and without limitation, the main chamber may be a single hollow container having a single compartment, or it may have several interlinked compartments. In some embodiments a main chamber could have a dumbbell shape, having two (or more) compartments linked by a conduit (e.g. a pipe or tube). Numerous other configurations are envisaged. In some embodiments flow control devices may be used to control the flow of material from one compartment of the main chamber to another.

An advantage of the present invention is that the shape of the main chamber is not constricted by the requirement to accommodate any internal mechanisms, such as a piston and piston cylinder. All that is required is that the main chamber is sealable (i.e. in its sealed condition it is air tight and capable of retaining any resilient material inserted into it) and that the liquid can flow relatively unhindered into and out of the main chamber through the inlet and outlet respectively. In this respect dimensional changes in the main chamber, due for example to the pressure exerted by the liquid when in use, do not affect the operation of the apparatus.

In a preferred embodiment the outlet extends upwards from the base of the main chamber.

An advantage of extending the outlet upwards is that the end of the outlet distal to the junction with the main chamber may be at a lower pressure than the pressure exerted by the liquid at the inlet to the main chamber.

Preferably the outlet should extend to at or near the surface of the liquid.

In some embodiments the outlet includes one or more outlet chambers.

Reference to an outlet chamber should be understood to refer to any compartment within the outlet (i.e. forming part of the outlet system between the connection with the main chamber and the end of the outlet distal to the main chamber). An outlet chamber may include flow control devices to control the flow of liquid into or out of the outlet chamber.

In a preferred embodiment the outlet includes an outlet flow control device having an open position configured to enable liquid to flow out of the main chamber and a closed position. Reference throughout this specification to an inlet or outlet flow control device should be understood to refer to any device configured to control the flow of material (liquid or gas) through the inlet or outlet respectively.

Preferably the flow control device is a valve.

Preferably the valve is self activated, for example by use of a weighted flap (or similar) which only opens (or shuts) when a pressure difference is sufficient to move the flap.

An advantage of a self activated valve is that no power is required to operate the valve. In some embodiments the valve may be activated by a solenoid which may be controlled remotely.

The location of the outlet connection to the main chamber, and in particular the height of the connection above the base of the main chamber, will depend on design specifications. The outlet connection must be below the level of liquid within the main chamber during operation of the apparatus as otherwise the resilient material could flow out of the main chamber when the outlet flow control device is opened, thus preventing or limiting further operation of the apparatus. The depth of liquid within the main chamber during use may depend on the size and shape of the main chamber, the inlet pressure of the liquid and the initial pressure of the resilient material. These factors can be used to calculate a suitable location for the connection to the outlet.

In a preferred embodiment an energy conversion device is located in the inlet.

In a preferred embodiment an energy conversion device is located in the outlet.

In embodiments where the main chamber has a plurality of compartments an energy conversion device may be located within a conduit connecting the compartments.

In a preferred embodiment the energy conversion device is a turbine.

The generation of electricity from a flow of material (gas/liquid) using a turbine is well known within the art.

In a further embodiment the energy conversion device may be an hydraulic or pneumatic system which utilises the pressure exerted by the resilient material to provide pressure to the pneumatic/hydraulic system. In this embodiment the main chamber is connected to the pneumatic/hydraulic system so that an increase of pressure through the inlet will raise the pneumatic/hydraulic pressure, while opening outlet valve will reduce it. The individual pressure can be altered by use of a valve between the main chamber and the pneumatic/hydraulic system.

In a preferred embodiment the apparatus includes one or more sensors configured to measure the flow of liquid into the main chamber, out of the main chamber, or through the main chamber.

In some preferred embodiments the apparatus includes one or more sensors configured to measure pressure within the main chamber, and/or to sense the performance of the energy conversion device, for example the speed of a turbine. BRIEF DESCRIPTION OF DRAWINGS

Further aspects of the present invention will become apparent from the following description which is given by way of example only and with reference to the accompanying drawings in which:

Figure 1 shows a schematic representation of an apparatus for generating energy

according to one embodiment of the present invention;

Figure 2 shows a schematic representation of an apparatus for generating energy

according to another embodiment of the present invention;

Figure 3 shows a schematic representation of an apparatus for generating energy

according to another embodiment of the present invention;

Figure 4 shows a schematic representation of an apparatus for generating energy

according to another embodiment of the present invention; and

Figure 5 shows a schematic flow chart of the method of the present invention as used in conjunction with the embodiment of Figure 2.

BEST MODES FOR CARRYING OUT THE INVENTION

An apparatus for generating energy according to one embodiment of the present invention is shown schematically in Figure 1. A sealable main chamber includes a first compartment, 1 , and a second compartment, 12, interconnected by a conduit 10. The conduit may be a pipe or tube of sufficient strength to withstand high pressure. An energy conversion device, in the form of a bi-directional turbine, 8, configured to generate electricity, is located in the conduit between the first and second compartments.

The first compartment is located deep within a body of water, 2, with the second compartment located on ground 11 above the surface of the water. This arrangement may assist with maintenance and access to the main chamber.

The first compartment includes an inlet 4 which is controlled by a flow control device in the form of a valve, 3, which when open enables water from the body of water to enter the first chamber. The valve is controlled from the surface by a control line 16.

An outlet, 5, is located within the first compartment at a position near the base of the first compartment. The outlet extends upwards from the base of the first compartment to an opening at atmospheric pressure just above the surface of the body of water. A resilient material, in the form of air, is introduced into the main chamber while it is sealed. The air may be compressed to an initial pressure above atmospheric pressure by a compressor connected to the second compartment.

In step c) of the method the valve 3 is opened allowing water to flow into the main chamber. The water is at a pressure which is equal to the product of the acceleration due to gravity, g, and the depth of the inlet below the surface of the water 2. The high pressure water

compresses the air in the main chamber above the initial pressure. This causes a flow of air up the conduit, this flow of air driving the turbine to generate electricity.

When the valve 3 is closed in step d) of the method, water is forced out of the main chamber and up the outlet 5. This change in pressure causes air to flow back from the second compartment towards the first compartment, thus driving the turbine from the opposite direction.

The valve 3 is then opened again in step e) thus allowing water to flow back into the first compartment to compress the air, thus repeating the process.

Another embodiment of the present invention is shown schematically in Figure 2. In this embodiment the main chamber, in the form of two compartments, 1 and 12, is located below a tank of water, 2. The main chamber is connected to the tank by an inlet 4. A turbine 8 is located in the inlet to generate electricity from the flow of water between the water in the tank and in the first and second compartments.

The first and second compartments are interconnected by branches from the inlet 4 with the connection of the inlet to each of the compartments controlled by valves 3. Control lines, 16, are provided to enable communication to operate the various valves and to the turbine.

Each of the first and second compartments include a further valve, 17, configured to enable additional water and/or air into each compartment if so required.

An outlet system, 5, completes the circuit by connecting each of the first and second

compartments of the main chamber back to the tank, the outlets entering the tank at a location above the level of water in the tank. The outlet system includes valves, 9, to control flow of water into and along the outlet.

In this embodiment air is introduced into both the first and second compartments. The method of operation is similar to that described above except that in this embodiment the valves to each of the first and second compartments are opened at various stages to allow water to flow into each compartment.

A further embodiment is shown schematically in Figure 3. In this embodiment the principle of the energy generator as described above is used to drive a pump action. A main chamber, in the form of a single compartment, 1 , is located deep within a man-made body of water 2. The body of water is fed from a source of water (e.g. a stream or lake for example) through a conduit 10. The main chamber includes an inlet 4 which includes a valve 3. The valve in this embodiment is self activated by pressure to open. A weight attached to the flap of the valve keeps the valve open allowing water to enter the main chamber. The flap closes when the pressure inside the main chamber reaches a level where the pressure differential counters the weight holding the flap open. The compressed air then pumps water out from the main chamber up the outlet 5.

Yet another embodiment is shown schematically in Figure 4 where the method is employed to generate thrust to propel a vehicle such as a boat 14. A main chamber, 1 , suitably streamlined to reduce drag, is deployed in water 2 below the boat by the outlet 5 (which may be attached to a side of the boat for example). The outlet is configured such that water pumped through the outlet by the action of the apparatus is directed away from the desired direction of travel.

An inlet valve 3 is located on the lower side of the main chamber. Operation of the inlet valve is controlled from the boat through communication lines 16. Similar communication lines are used to open and shut a valve 9 controlling water leaving the outlet.

Air is introduced into the main chamber prior to opening the inlet valve 3. The incoming flow of water compresses the air. When the inlet valve is closed and the outlet valve 9 opened, the compressed air forces water up and out of the outlet, the force of the water leaving the outlet providing propulsion to the boat. A swivel socket 19 allows the direction of the force to be changed.

Figure 5 shows a flow chart indicating the steps of the method as used with the embodiment of the present invention illustrated in Figure 2.

The Applicant considers that the present invention may have a number of advantages over the prior art, including: · simplicity of construction as the components are generally not constrained by internal mechanisms such as pistons and cylinders;

simplicity of operation, as the only controls required are to operate the inlet and outlet valves;

• low cost construction due to simplicity of design;

• low operating cost;

• versatility in regard to where it may be used, as the apparatus may be placed and

operated in natural and man-made bodies of water; and

• versatility of operation, in that it may be used to generate electrical power, as a pump, as a method of propulsion through water, and to provide pressure to operate a pneumatic or hydraulic system. Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope thereof of the appended claims.

Claims

WHAT I CLAIM IS:

1. A method of generating energy from the flow of material through, into or out of a high pressure sealable main chamber, the main chamber including an inlet with an inlet control device having an open position in which the material can flow into the main chamber and a closed position, and an outlet, the method including the steps of:

a) inserting a resilient material into the main chamber and sealing it;

b) locating the inlet of the main chamber at a depth within a body of liquid; c) setting the inlet flow control device to the open position to enable the liquid to flow into the main chamber thus compressing the resilient material; d) setting the inlet flow control device to the closed position to enable the resilient material in the main chamber to expand and displace at least some of the liquid in the main chamber out through the outlet;

e) repeating steps c) and d) to create a flow of fluid and resilient material through the main chamber; and

f) extracting energy from the flow of the resilient material and/or the liquid through the main chamber, and/or of the liquid into or out of the main chamber.

2. The method as claimed in claim 1 wherein the resilient material is inserted into the main chamber after the inlet of the main chamber is located at a depth within the body of liquid.

3. The method as claimed in either claim 1 or claim 2 including the step of using a pump to aid removal of the liquid removed from the main chamber in step d).

4. The method as claimed in any one of claims 1 to 3 including the step of adding

compressed resilient material to the main chamber in step d).

5. The method as claimed in any one of claims 1 to 4 wherein the liquid is water.

6. The method as claimed in any one of claims 1 to 5 wherein the resilient material is a gas.

7. The method as claimed in claim 6 wherein the gas is air.

8. The method as claimed in any one of claims 1 to 7 wherein the main chamber is located at a depth of at least 2 meters within the body of liquid.

9. An apparatus for generating energy including:

a high pressure sealable main chamber having an inlet located in the vicinity of a base of the main chamber, the inlet including an inlet flow control device having an open position in which liquid can flow into the main chamber and a closed position; and an outlet having an opening located at a position which, in use, is below the level of liquid in the chamber; and at least one energy conversion device configured to extract energy from the flow of liquid into the main chamber, out of the main chamber, or through the main chamber.

10. An apparatus as claimed in claim 9 wherein the main chamber includes a plurality of interlinked compartments.

11. An apparatus as claimed in either one of claims 9 or 10 wherein the outlet extends

upwards from the base of the main chamber.

12. An apparatus as claimed in any one of claims 9 to 11 wherein the outlet includes one or more outlet chambers.

13. An apparatus as claimed in any one of claims 9 to 12 wherein the outlet includes an outlet flow control device having an open position configured to enable liquid to flow out of the main chamber and a closed position.

14. An apparatus as claimed in any one of claims 9 to 13 wherein an energy conversion device is located in the inlet.

15. An apparatus as claimed in any one of claims 9 to 14 wherein an energy conversion device is located in the outlet.

16. An apparatus as claimed in any one of claims 9 to 15 wherein an energy conversion device is located within a conduit connecting the compartments.

17. An apparatus as claimed in any one of claims 9 to 16 wherein the energy conversion device is a turbine.

18. A method substantially as herein described with reference to and as illustrated by the accompanying description and drawings.

19. An apparatus as herein described with reference to and as illustrated by the

accompanying description and drawings.