GB2060815A - Energy storage system - Google Patents

Abstract

A process for storing energy and subsequently releasing said energy, includes utilising said energy to lift a load from a lower position to an elevated position, storing said load in said elevated position to provide a source of stored energy and subsequently releasing said load into a space in which it can descend under control and using said descending load to drive an energy operated mechanism. The energy used to lift the load may be derived from solar radiation.

Description

SPECIFICATION Energy storage system This invention relates to a process and apparatus for storing energy and for subsequently releasing said energy so as it can be used to drive an energy operated mechanism.

Various forms of energy are available as fuel for operating mechanisms used at the present time. Fuels such as oil or other carbonaceous materials can be readily stored and used as required as the materials themselves contain the energy which can subsequently be released. Similarly energy can be stored by arranging for a liquid to be carried in a reservoir so that the height of the liquid and its weight can be used as a form of energy, for example, hydro-electric schemes.

Another well known form of energy is that provided by solar radiation but, at the present time, there is no way of storing such energy in large quantities. It is known to concentrate solar energy so that its heat can be used to raise the temperature of, for example, water to provide steam, to utilise the steam to operate a turbine and the turbine to drive a generator.

Even by this method however the electricity generated has to be used as it is produced although it is of course possible to store relatively small quantities of electricity by the well-known types of batteries so that such energy can be used at a later period. A difficulty with this system however, is that the batteries will not store the energy indefinitely and, as mentioned above, the amount of energy which can be stored is relatively small compared, for example, to the electrical power required for operating an electrically energised power system for a town or city or other large power consumer.

The use of a descending load is employed in hydro-electric schemes; in this case the load being provided by the weight of water above the water operated turbine but such hydro-electric schemes have very considerable disadvantages. Thus, they first require a source of water, which is not available in many places. They also usually require a very large area in which to store the water in the form of a lake or reservoir and this is liable to evaporation and leakage. Moreover, the efficiency of the water driven turbines is not high so that there are considerable losses. In the process and apparatus according to the invention however such criteria do not apply because it is almost always possible to gather solar energy during daylight hours and the storage apparatus can be constructed anywhere.

One object of the present invention is to provide a process and apparatus for storing the energy for prolonged periods so that it is possible to use it on demand and with relatively small loss quantity.

According to one aspect of the present invention therefore a process for storing energy and subsequently releasing said energy, includes utilising said energy to lift a load from a lower position to an elevated position, storing said load in said elevated position to provide a source of stored energy and subsequently releasing said load into a space in which it can descend under control and using said descending load to drive an energy operated mechanism.

With the invention therefore the solar energy can be used to lift the load which can be available for release at any time so that a continuous supply of energy is available by first converting the solar radiation into a different form of energy which is utilised to lift said load.

The storage means according to the invention can be incorporated in a hillside which has conservation advantages when compared with a hydro-electric scheme which involves building a damm and the covering of large tracts of land. A further disadvantage with hydro-electric schemes is that cost of buying large areas of land and the high cost of transmission and electricity since damns are normally not located close to towns or cities.

These disadvantages are overcome by the present invention in which the area of land required is small and the equipment can be located close to a town or city.

A further advantage is that with a reservoir insufficient water may be produced during a dry summer whereas such a summer with a high sunlight rate is advantageous in the present invention.

Yet further advantages are that damns always create the danger of flooding and the cost of heavy maintainence.

It will be appreciated that a plant according to the invention can be provided at the outskirts of any town or city and is preferably located on a hill facing south, the system absorbs only the solar radiation which is free and does not take away energy from any other part of the earth's system. Moreover, the energy obtained can be stored indefinitely and used as required.

Various forms of energy can be employed as the different form of energy, for example, a pressurised fluid or gas such as steam, or electricity which is supplied to an energy converter to provide movement to lift said load, or the solar radiation can be used to cause a solid, liquid or gas to expand said expansion being used as said different form of energy.

Thus, the energy converter can include a machine which produces a motion which is used to operate an electrical supply device for example by using the pressurised fluid to drive a turbine which operates an electrical generating device.

Alternatively, the energy converter can in dude a machine which produces a motion which is used to lift said load through a power transmission and said power transmission can include an hydraulic, pneumatic or mechanically operated device such as a pump engine or gear box to lift the load.

In an alternative process when the different form of energy is electricity this can be supplied to an energy converter to provide movement to lift said load and the electricity can be obtained from, for example, solar cells.

The solar energy may be collected by any means, for example it may be intercepted in space by satellite and beamed to earth as an intense beam, or it can be collected as it reaches the earth's surface.

In any case, preferably a solar furnace is used to harnass the solar radiation by focusing its heat and light and the heat thus provided is preferably used to heat a boiler to raise steam to drive a steam turbine which operates an electrical generator.

The load can be raised by many kinds of device which may be mechanical, hydraulic or pneumatic, but preferably when a steam turbine is used to operate an electrical generator the electricity generated thereby is used to actuate an electric motor which operates to lift the load from a lower to an elevated position.

The load can be provided in any convenient form liquid, semi-liquid or solid but preferably a solid weight of heavy mass is used. Thus each of the loads can be in the form of a mobile substance and is stored at said elevated position in a container, for example the substance can be a liquid, semi-liquid, powder or particles and these, if desired, could be pumped up to the elevated storage position.

In a preferred embodiment of the process a number of loads are raised and stored at the elevated position, the process including moving them from the elevated position to a ready use position from which they can be lowered.

The invention also includes apparatus for storing energy and for subsequent release of said energy, which includes means for converting energy provided by solar radiation into another form of energy, lifing means operated by said energy to lift a load from a lower position to an elevated position, storage means for storing said load in said elevated position to provide a source of stored energy and release means which can be operated to release said load into a space in which it can descend, control means for controlling said descent and drive means which are operated by said descending load and which drive an energy operated mechanism.

If the energy is solar radiation means can be provided for converting it into a different form of energy which is used to operate said lifting means.

The invention can be performed in various ways and some embodiments of apparatus for carrying out the process will now be described by way of example and with reference to the accompanying drawings in which: Figure 1 is a diagrammatic view of apparatus which can be used for carrying out the process according to the invention; Figure 2 is a diagrammatic view of one form of lifting mechanism and control means; Figure 3 is an enlarged view of part of control means as shown in Fig. 2; and, Figure 4 is a diagrammatic view of an alternative form of control means.

As shown in Fig. 1 the apparatus inludes means for gathering solar radiation, converting it into a different form of energy and means for storing the available energy so that it can be used immediately or at some later date and without deterioration or substantial loss.

In Fig. 1 the sun is indicated by reference numeral 1, this being the source of the solar radiation. The radiation is gathered by known means which, in the embodiment being described comprises what is referred to as a solar furnace, indicated generally by reference numeral 2. This solar furnace consists of a reflector 3 which gathers the suns rays and concentrates them onto a furnace mirror 4.

The subsequent heat is transferred to a boiler 5 which draws water from a supply line 6 through a water tank 7 to provide high pressure steam to a turbine 8. It will be appreciated that the design of the boiler can take many forms as can the design of the focussing device for the solar radiation. It is at the present time possible to gather solar radiation in this manner sufficiently to heat a furnace up to 3000"C which is hot enough to melt metals, the heat being completely clean and uncontaminated by fuel gases. In the present apparatus this heat is concentrated on the boiler to raise the steam for driving the turbine 8.

In another form of radiation gathering device (not shown) a set of flat mirrors are used which are arranged to follow the path of the sun and reflect the rays onto a stationary furnace mirror. Tracking mirrors of this kind are known as heliostats and can be driven by electric motor so that they move through 50 minutes of arc during each energy hour. Alternatively the angle of the heliostat may be controlled by a photocell or thermo-couple that detects the absence of light or heat rays.

Similarly the design of the turbine 8 can also take many forms and these, to some extent, dependent upon'the boiler system and the type of steam which is available, back pressure, exhaust steam or a condensing turbine could be used.

It will be appreciated that the apparatus first described acts to convert the solar radiation into a different form of energy, in this case high pressure steam which is used to drive the turbine.

The energy available in the turbine is now used to drive apparatus which can be used for physically moving a load. The rotary movement of the turbine shaft can therefore be used to drive an electric generator or a transmission gear box or even a hydraulic system, this movement being utilised to operate as a crane to lift the load. In the arrangement shown in Fig. 1 an electric generator is indicated by reference numeral 9 and this is used to operate electrical lifting mechanism 10.

This lifting mechanism acts to lift a number of loads which are in the form of weights 11. In the apparatus being described the weights are made from concrete and each weigh about 50 metric tonnes. Each weight consists of 9 cubic yards of material which can be acheived by making the weight approx. 3 meters by 2 meters by one meter. In Fig. 1 only one weight is shown. The weight is mounted on a lower rail 1 2 which leads to a vertically rising rail 1 3. Mounted at the upper end of the rail 1 3 are a number of storage rails 14, 15, 16, 1 7 and these branch off from the rail 1 3 by adjustable junctions, not shown.Each of the storage rails is oblique to the horizontal extending at an angle of about 5" from its receiving end 1 8 to its despatch end 1 9. At their despatch ends 1 9 the rails engage another vertically arranged guide rail 20 onto which they can be individually switched by switch means again not shown. Arranged alongside the rail 20 are control means indicated by reference numeral 21, to be described, and at the lower end is an energy operated mechanism indicated by reference numeral 22, this mechanism driving an electric generator 23.

The electrical lifting mechanism 10 is used to raise the weight 11 up the rail 1 3 and, for example, deposit it on the receiving end 1 8 of the storage rail 1 4 which constitutes a delivery position. Due to the inclination of the storage rail 1 4 the weight 11 will slowly move to the despatch end 1 9. At this point, or at any point along rail 14 the weight 11 represents a source of stored energy due to the effects of gravity. When the energy is required it is merely necessary to connect the weight 11 to the control means 21 and allow the weight to descend under control down the rail 20. The control means 21 also drives the energy operated mechanism 22 to produce a second form of energy, in this case electricity from the generator 23.

It will therefore be appreciated that the apparatus enables energy, in the form of the weight 11 to be stored for any period of time but to be immediately available, in the case for transfer into electricity.

As shown in Fig. 1 the apparatus is intended to be available to supply electricity to a small town and to achieve the energy requirements the rail 1 3 could be about 500 meters high and each of the storage rails 14, 15, 16, 1 7 would be sufficiently long to store about 20 weights; more storage rails could be provided as desired. It will be appreciated that the storage rails could be arranged vertically above each other, horizontally side by side or in any other convenient fashion. The control means 21 can incorporate means for sensing the load on the generator 23 so that as the load increases the control means allow the weight to fall faster to produce more energy over a given period to meet the demand.

As mentioned above the load to be lifted can be in any convenient form and if weights are used they can be made from any heavy substance which can be solid or semi solid, for example they can be made from re-inforced concrete, of various shapes, and the concrete can be mixed with other material with heavier specific weight of gravity such as barite or bentonite. Again, the weights can be made from a heavy substance in the form of a semi solid powder or particles with the capability of being pumped into containers of metal or plastic or various shapes and, in one embodiment, not shown, the power available from the turbines could be used to pump a semi-liquid material up to a higher level rather than using it to lift a solid weight.Again, the load to be raised could be liquid but it is preferable to use the liquid in, for example, a container when delivering the energy from it rather than attempting to rely upon a water driven turbine because the energy loss is such hydraulically operated devices is considerable but, nevertheless, this is within the scope of the present invention.

In the arrangement described above the descending weight is used to generate electricity but, it could, if desired, be used to operate any form of energy operated mechanism, for example, a pump or a mechanically rotated shaft so that the energy therefrom can be used for other purposes.

Preferably the load raised is substantially inert, so that there is no loss due to outside sources, whilst it is in storage.

The storage apparatus can be built as a building or can be arranged on a hillside thus utilising the available height differential.

Again, the load may not be raised up a vertical track or shaft but can be raised or allowed to descend on an incline. The use of a vertical lift and descent however is preferable in order to reduce frictional losses.

If the arrangement is substantially as shown in Fig. 1 and weights 11 are used then the lifting mechanism 10 can include a suitable lifting crane which incorporates an appropriate purchase to obtain a suitable mechanical advantage.

It will be appreciated that there are many ways of providing the lifting mechanism 10 and the energy operated mechanism indicated by reference numeral 22 in Fig. 1. A simple construction is shown in Figs. 2 and 3. In these Figures the same reference numerals are used to indicate similar parts to those in Fig.

1. It will be seen that the lifting mechanism 10 includes a lifting shaft 24 driven by appropriate gearing from the electric generator 9 or by any other mechanism which is provided in its place to produce a rotary movement. This drive shaft 24 carries a toothed wheel 25 around which extends a roller chain 26. This continuous roller chain 26 is also engaged by a toothed wheel 27 arranged above the storage rail 1 4. Each of the weights 11 carries two pairs of hooks 28 which are shaped to engage the chain 26. Thus, when the weight 11 is moved into an appropriate position the chain 26 is used as a crane to lift the weight up to the storage rail 1 4 where it can be disengaged from the chain and allowed to ride down the rail where it is to be kept in storage.

In this simple arrangement the control mechanism 21 is provided by another roller chain 29 which extends around an upper toothed wheel 30 and a lower driven toothed wheel 31 mounted on a power shaft 32. The power shaft 32 passes through a gear box 33 which subsequently drives the electrical generator 23 through a shaft 34. When electrical energy is required it is merely necessary to engage the appropriate set of hooks 28 on the weight 11 with the chain 29 and allow the weight to descend down the guide rail 20.

As the weight descends it will cause the chain to rotate the toothed wheel 31 and thus the power shaft 32 to drive the electrical generator 23.

Fig. 3 shows a more detailed view of the power shaft 32 and shows a fly wheel 35 and mounting bearings 36.

In Fig. 4 another form of power take off is shown. In this case the weight 11 is provided with a pair of rotatable shafts 36, 37. Each shaft is mounted to rotate in the weight 11 and each carries a rigidly connected spur gear 38, 39. The spur gears engage a toothed rail 40 mounted parallel to the guide rail 20 on which the weight descends. The arrangement is such that the downward movement of the weight 11 causes the spur gears 38, 39 to rotate as they engage the toothed rail 40 which thus causes rotation of the shafts 36, 37. Fly wheels 41, 42 are provided on the shafts and each shaft drives a hydraulic pump, indicated by reference numerals 43, 44.Suitable hydraulic lines (not shown) are attached to the pumps so that the descending weight is used to create a hydraulic pressure which can be used to drive, for example, hydraulic motors to energise an electrical generator or for any other power purpose.

It will be appreciated that the above examples are intended to represent only very simple applications of the invention and the method of raising the weights 11 and utilising them to produce power as they descend can take many forms In the arrangement shown in Figs. 2 and 3 the control of the descending weight is achieved through the roller chain 29 by arranging for suitable gearing in gear box 33, thus ensuring that the weight descends at a given rate to produce a given output by the electrical generator 23.

In Fig. 4 control of the rate of descent can be achieved by design of the hydraulic pumps which will supply a back torque through the drive shafts to restrict the rate of descent of the weight 11. Yet again it will be appreciated that many forms of control for the weight can be provided without effectively reducing the energy available from the descending weight.

In the arrangements described above the "different form of energy" is provided by a pressurised fluid but in an alternative arrangement this energy could be in the form of electricity derived directly from the solar radiation by solar cells. The use of such cells are well known in themselves and will not therefore be described in further detail but provided sufficient cells are used sufficient energy could be gathered to produce the necessary electricity to operate the apparatus. Again means could be included for using said solar energy to cause a solid, liquid or gas to expand, and to use this expansion as the different form of energy.

Claims (52)

1. A process for storing energy and subsequently releasing said energy, which includes utilising said energy to lift a load from a lower position to an elevated position, storing said load in said elevated position to provide a source of stored energy and subsequently releasing said load into a space in which it can descend under control and using said descending load to drive an energy operated mechanism.

2. A process as claimed in claim 1 in which said energy is provided by solar radiation and is first converted into a different form of energy which is utilized to lift said load.

3. A process as claimed in claim 2 in which said solar radiation is used to cause a solid, liquid or gas to expand, said expansion being used as said different form of energy.

4. A process as claimed in claim 2 or claim 3 in which said different form of energy is a pressurised fluid or gas which is supplied to an energy converter to provide movement to lift said load.

5. A process as claimed in claim 4 in which said pressurised fluid is steam.

6. A process as claimed in claim 4 and claim 5 in which said energy converter includes a machine which produces a motion which is used to operate an electrical supply device.

7. A process as claimed in claim 6 in which said pressurised fluid is used to drive a turbine which operates an electric generating device.

8. A process as claimed in claim 4 and claim 5 in which said energy convertor includes a machine which produces a motion which is used to lift said load through a power transmission.

9. A process as claimed in claim 8 in which said power transmission includes an hydraulic device.

10. A process as claimed in claim 8 in which said power transmission includes a pneumatic device.

11. A process as claimed in claim 8 in which said power transmission includes a mechanically operated device.

1 2. A process as claimed in claim 2 in which said different form of energy is electricity which is supplied to an energy converter to provide movement to lift said load.

1 3. A process as claimed in claim 1 2 in which said electricity is obtained from solar cells.

14. A process as claimed in any one of preceding claims 2-1 3 in which said solar energy is intercepted in space by satellite and beamed to earth as an intense beam.

1 5. A process as claimed in any one of the preceding claims in which control means are used to control the descent of said load, said control means also driving an energy operated mechanism to produce a second source of energy.

16. A process as claimed in claim 1 5 in which said second source of energy is electricity which is produced by an electric generating device.

1 7. A process as claimed in any one of the preceding claims in which a number of loads are raised and stored at the elevated position and are then moved to a ready use position from which they can be lowered.

18. A process as claimed in any one of the preceeding claims in which each of said loads is in the form of a mobile substance and is stored at said elevated position in a container.

19. A process as claimed in claim 18 in which said substance is a liquid, semi-liquid, powder or particles.

20. A process as claimed in claim 1 8 or claim 1 9 in which said mobile substance is pumped up to the elevated storage position.

21. Apparatus for storing energy and for subsequently releasing said energy which includes lifting means operated by said energy to lift a load from a lower position to an elevated position, storage means for storing said load in said elevated position to provide a source of stored energy and release means which can be operated to release said load into a space in which it can descend, control means for controlling said descent and drive means which are operated by said descending load and which drive an energy operated mechanism.

22. Apparatus as claimed in claim 21 in which said energy is solar radiation and means for converting it into a different form of energy which is used to operate the lifting means.

23. Apparatus as claimed in claim 22 including means for using said solar energy to cause a solid, liquid or gas to expand, and using said expansion as the different form of energy.

24. Apparatus as claimed in claim 23 or claim 24 in which said different form of energy is a pressurised fluid and means for supplying said fuel to an energy converter which provides movement to lift said load.

25. Apparatus as claimed in claim 1 9 in which said pressurised fluid is steam.

26. Apparatus as claimed in claims 21-25 in which said energy converter includes a machine which produces a motion which is connected to operate an electrical supply device.

27. Apparatus as claimed in claim 26 when dependent upon claims 24 and 25 in which said pressurised fluid drives a turbine which is operatively connected to an electric generating device.

28. Apparatus as claimed in claims 21-25 in which said energy converter includes a machine which produces a motion to lift said load through a power transmission.

29. Apparatus as claimed in claim 28 in which said power transmission includes a hydraulic device.

30. Apparatus as claimed in claim 29 in which said hydraulic device includes a ram.

31. Apparatus as claimed in claim 28 in which said power transmission includes a pneumatic device.

32. Apparatus as claimed in claim 31 in which said pneumatic device includes a ram.

33. Apparatus as claimed in claim 28 in which said power transmission includes a torque converter or gear box.

34. Apparatus as claimed in claim 22 in which said different form of energy is electricity, and means for supplying said electricity to an energy converter to provide movement to lift said load.

35. Apparatus as claimed in claim 34 in which said electricity is obtained from solar cells.

36. Apparatus as claimed in claim 22 which includes a satellite to intercept said solar energy in space and beam it to earth as an intense beam.

37. Apparatus as claimed in claims 26, 27 and 36 including an electric machine which is driven by said electricity and which operates to lift said load.

38. Apparatus as claimed in claim 22 including a heliostat which gathers said solar energy.

39. Apparatus as claimed in any one of preceding claims 21-38 in which said load is in the form of a weight.

40. Apparatus as claimed in any one of preceeding claims 21-38 in which each of said loads is in the form of a mobile substance and is stored in said elevated position in a container which provides a weight.

41. Apparatus as claimed in claim 40 in which said substance is a liquid, semi-liquid, powder or particles.

42. Apparatus as claimed in claim 40 or claim 41 including means for pumping said mobile substance up to the elevated storage position.

43. Apparatus as claimed in any of claims 39, 40, 41 or 42 in which a number of weights are provided.

44. Apparatus as claimed in claim 43 in which said weights are mounted on interconnected guide means along which they can be moved by said different form of energy.

45. Apparatus as claimed in claim 44 in which said guide means includes a rail system.

46. Apparatus as claimed in claim 44 or claim 45 in which said guide means includes an elevated storage location where the guide means is inclined to cause said weights to move from a delivery position to a despatch position.

47. Apparatus as claimed in any one of the preceding claims 21-46 including control means to control the descent of said load, said control means being connected to drive an energy operated mechanism to produce a second source of energy.

48. Apparatus as claimed in claim 47 in which said energy operated mechanism produces electricity.

49. Apparatus as claimed in claim 47 or claim 48 in which said control means incorporates means for sensing the load on the energy producing mechanism, said means acting to cause the control means to allow the load to fall faster to produce more energy to meet said load.

50. Apparatus as claimed in any one of the preceding claims installed in a hillside.

51. Apparatus for storing and subsequently releasing energy substantially as described herein with reference to and as shown in Fig. 1, Fig. 2 and Fig. 3 or Fig. 4 of the accompanying drawings.

52. A process for storing energy and subsequently releasing said energy, substantially as described herein with reference to and as shown in Fig. 1, Fig. 2 and Fig. 3 or Fig. 4 of the accompanying drawings.