AN ELECTRICI TY GENERATING DEVICE , A FLUID PRESSURE REDUCING DEVICE , AND A FLUID PUMP
Field of the Invention
The present invention relates to an electricity generating device, in particular to such a device for generating electricity from a moving fluid such as water, to a fluid pressure reducing device, and to a fluid pump.
Background of the Invention
It is known that significant energy is associated with a moving fluid. For example, in a conventional multi-storey building significant energy will be associated with water flowing through downward water pipes extending between elevated water access points and waste water receiving points generally located at or below ground level.
Similarly, significant energy is associated with moving water in a body of water such as a flowing river or tidal flows in an ocean or sea.
Summary of the Invention In accordance with a first aspect of the present
invention, there is provided an electricity generating device comprising:
a fluid inlet;
a fluid outlet; and
an alternator having a stator and a rotor, the rotor being hollow and in fluid communication with the fluid inlet and the fluid outlet;
wherein the rotor is associated with a rotation imparting device disposed in the rotor and arranged such that fluid flowing from the fluid inlet to the fluid outlet cooperates with the rotation imparting device so as to effect rotation of the rotor relative to the stator and
thereby generation of electricity; and
wherein the rotation imparting device comprises a plurality of adjacently disposed blades or vanes, each blade or vane extending partly around a central axis of the rotor.
In one embodiment, the device comprises a pipe portion, the rotor mounted on the pipe portion. In one embodiment, the device comprises a first pipe coupling device arranged to rotatably connect the pipe portion to a fluid inlet pipe, and a second pipe coupling device arranged to rotatably connect the pipe portion to a fluid outlet pipe.
The pipe portion may comprise first and second flanges at respective longitudinal ends of the pipe portion, each of the first and second flanges serving to facilitate
connection of the pipe portion to a pipe coupling device.
In one embodiment, the pipe coupling device comprises a thrust bearing.
In one embodiment, the rotation imparting device is integrally formed with the pipe portion.
In one embodiment, the rotor comprises the rotation imparting device. In one embodiment, the rotation imparting device is integrally formed with the rotor.
In one embodiment, the device comprises a bearing mounted adjacent each longitudinal end of the rotor, each bearing being received in a respective bearing channel associated with the stator.
In one embodiment, the rotation imparting device comprises a central hub mounted in a hollow portion of the rotor, the plurality of blades or vanes being disposed around the central hub and the central hub arranged to urge fluid to move towards the blades or vanes.
In an embodiment, the blades or vanes are connected to the rotor and arranged to rotate around the central hub. In an embodiment, the blades or vanes are spaced from the central hub by about 0.05mm.
In an embodiment, each of the blades or vanes is connected to the central hub such that fluid is still able to pass between the blade or vane and the central hub. Each blade or vane may be connected to the central hub at a spot connection .
In an embodiment, the device comprises a shaft extending through the rotor, the central hub mounted on the shaft, the blades or vanes connected to the shaft and the rotor, and the shaft mounted adjacent longitudinal ends to respective bearings so as to facilitate rotation of the hub, blades or vanes, and rotor relative to the stator.
In an embodiment, each end of the shaft is connected through a bearing to a spoke and rim arrangement, the spoke and rim arrangement disposed between adjacent non- rotating pipe sections.
In one embodiment, the device comprises a fluid bypass device arranged to controllably divert fluid around the rotor during use. The fluid bypass device may comprise at least one valve and at least one bypass pipe, the or each valve being controllable so as to selectably direct fluid to the pipe portion or to the bypass pipe.
In accordance with a second aspect of the present
invention, there is provided an electricity generating system comprising:
an electricity generating device according to the first aspect of the present invention;
an inlet pipe connected to the fluid inlet of the electricity generating device; and
an outlet pipe connected to the fluid outlet of the electricity generating device.
In one embodiment, the inlet pipe and the outlet pipe are part of a water distribution pipe network.
In one embodiment, the water distribution pipe network is a building water distribution pipe network.
The inlet pipe and the outlet pipe may be part of a downpipe of a building water distribution pipe network. In one embodiment, the system comprises a plurality of electricity generating devices.
In an embodiment, the electricity generating device comprising comprises at least one funnel member arranged to direct water towards the hollow rotor.
In one embodiment, the electricity generating device comprises an anchoring arrangement for anchoring the alternator and the at least one funnel member relative to a floor of a body of water.
In one embodiment, the device comprises first and second funnel members respectively arranged so as to direct water to an opposite side of the hollow alternator.
In one embodiment, the device comprises a filter member associated with each funnel member, each filter member
arranged to restrict passage of material above a defined size towards the alternator.
In accordance with a third aspect of the present
invention, there is provided a fluid pressure reducing device comprising an electricity generating device
according to the first aspect of the invention.
In accordance with a fourth aspect of the present
invention, there is provided a fluid pump comprising:
a fluid inlet;
a fluid outlet; and
a motor having a stator and a rotor, the rotor being hollow and in fluid communication with the fluid inlet, and the rotor being arranged to rotate in response to an electrical signal applied to the stator;
wherein the rotor is associated with a fluid movement imparting device arranged such that when the rotor rotates relative to the stator in response to application of an electrical signal to the stator, fluid cooperates with the fluid movement imparting device so as to cause fluid to flow from the fluid inlet to the fluid outlet; and
wherein the fluid movement imparting device comprises a plurality of adjacently disposed blades or vanes, each blade or vane extending partly around a central axis of the rotor.
In an embodiment, the fluid pump comprises a pipe portion, the rotor mounted on the pipe portion. In an embodiment, the fluid movement imparting device is integrally formed with the pipe portion.
In an embodiment, the rotor comprises the fluid movement imparting device.
In an embodiment, the fluid movement imparting device is integrally formed with the rotor.
In an embodiment, the fluid pump comprises a bearing mounted adjacent each longitudinal end of the rotor, each bearing being received in a respective bearing channel associated with the stator.
In an embodiment, the fluid movement imparting device comprises at least one blade or vane. In an embodiment, the fluid movement imparting device comprises a central hub mounted in a hollow portion of the rotor, the plurality of blades or vanes being disposed around the central hub. In an embodiment, the blades or vanes are connected to the rotor and arranged to rotate around the central hub.
In an embodiment, the blades or vanes are spaced from the central hub by about 0.05mm.
In an embodiment, each of the blades or vanes is connected to the central hub such that fluid is still able to pass between the blade or vane and the central hub. Each blade or vane may be connected to the central hub at a spot connection.
In an embodiment, the fluid pump comprises a shaft
extending through the rotor, the central hub mounted on the shaft, the blades or vanes connected to the shaft and the rotor, and the shaft mounted adjacent longitudinal ends to respective bearings so as to facilitate rotation of the hub, blades or vanes, and rotor relative to the stator . In an embodiment, each end of the shaft is connected through a bearing to a spoke and rim arrangement, the spoke and rim arrangement disposed between adjacent non-
rotating pipe sections.
Brief Description of the Drawings The present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:
Figure 1 is a diagrammatic cross-sectional view of an electricity generating device in accordance with an embodiment of the present invention with the device shown during use incorporated into a fluid pipe;
Figure 2 is a diagrammatic cross-sectional view of an electricity generating device in accordance with a further embodiment of the present invention with the device shown during use incorporated into a fluid pipe;
Figure 3 is a diagrammatic cross-sectional view of a 2-part pipe portion of an electricity generating device in accordance with an embodiment of the present invention;
Figures 4a and 4b are diagrammatic representations of part of a rotation imparting device of an electricity generating device in accordance with an embodiment of the present invention;
Figures 5a and 5b are diagrammatic representations of an alternative rotation imparting device of an electricity generating device in accordance with an embodiment of the present invention;
Figure 6 is a diagrammatic cross-sectional view of an electricity generating device in accordance with an embodiment of the present invention provided with a bypass pipe;
Figure 7 is a diagrammatic perspective view of an electricity generating device in accordance with an alternative embodiment of the present invention;
Figure 8 is a diagrammatic perspective exploded view of an alternator of the electricity generating device shown in Figure 7;
Figure 9 is a diagrammatic perspective exploded view
of the electricity generating device shown in Figure 7 ;
Figure 10 is a diagrammatic cross sectional view of the electricity generating device shown in Figure 7 ;
Figure 11 is a diagrammatic view of an electricity generating device in accordance with an alternative embodiment of the present invention during use;
Figure 12 is a diagrammatic cross-sectional view of the electricity generating device shown in Figure 11;
Figure 13 is a diagrammatic view of an electricity generating device in accordance with a further alternative embodiment of the present invention during use; and
Figures 14 to 17 are diagrammatic views of a further alternative embodiment of an electricity generating device in accordance with the present invention.
Description of an Embodiment of the Invention
Referring to Figure 1, an electricity generating device 10 for generating electricity from a flowing fluid is shown. In this example, the electricity generating device 10 is incorporated into a fluid pipe by disposing the
electricity generation device 10 between an inlet pipe section 12 and an outlet pipe section 14. In this example, the fluid pipe is a water pipe forming part of a water distribution pipe network in a multistorey building and, in this particular example, the water pipe is a downward water pipe extending between an
elevated water distribution point in the building and a waste water point disposed at or below ground level.
However, it will be appreciated that the electricity generating device 10 may be incorporated into any suitable fluid pipe wherein sufficient energy is associated with the fluid flowing through the fluid pipe to generate electricity.
In the preset embodiment, the device 10 includes a pipe
portion 16, in this example of generally cylindrical form, and a first flange 18 connected to each longitudinal end of the pipe portion 16, for example by welding.
Similarly, each of the inlet and outlet pipe sections 12, 14 includes a second flange 20 connected to a free end of the inlet and outlet pipe sections 12, 14, for example by welding .
The pipe portion 16 is connected to the inlet and outlet pipe sections 12, 14 through bearings 22, for example thrust bearings, each bearing 22 being disposed between adjacently disposed first and second flanges 18, 20 and connected to the first and second flanges 18, 20 in any suitable way, for example using bolts 23. In one
embodiment, the bearings are magnetic bearings.
It will be understood that the bearings 22 serve to connect the device 10 to the inlet and outlet pipe
sections 12, 14 whilst permitting the pipe portion 16 to freely rotate about a longitudinal axis of the pipe portion 16. As such, it will be appreciated that any pipe coupling device arranged to connect the pipe portion to an inlet pipe or an outlet pipe such that the pipe portion is rotatable relative to the pipe inlet or pipe outlet whilst providing a good seal to prevent egress of fluid from the inlet pipe, outlet pipe and pipe portion 16 is envisaged.
The device 10 also includes a rotation imparting device 24. The rotation imparting device 24 serves to cause the pipe portion 16 to rotate during use when fluid passes through the pipe portion 16 in the direction of Arrows A.
In this example, the rotation imparting device 24 includes a fluid directing device having a cross member 26
extending across and fixed to the outlet pipe section 14, a shaft 28 extending generally perpendicularly from the cross member 26, and a fluid directing member 32 mounted
on the shaft 28. In this example, the fluid directing member 32 is in the form of a central hub portion having a generally convex end profile that faces water flow during use .
The rotation imparting device 24 also includes a plurality of vanes 34 connected to the pipe portion 16 and disposed adjacent the hub portion 32 so that a small gap, in this example about 0.05mm, is defined therebetween. The vanes 34 are configured and disposed relative to the hub portion 32 so that water flowing through the pipe portion 16 during use in the direction of Arrow A impinges on the vanes 34 and thereby causes the vanes 34 to rotate about the central hub portion 32 and the pipe portion 16 to rotate relative to the inlet and outlet pipe sections 12, 14. The fluid directing member 32 is arranged to urge fluid to move towards the vanes 34 during use.
The hub portion 32 and the vanes 34 are shown more
particularly in Figure 4 and in this example four vanes 34 equidistantly disposed around the hub portion 32 are provided. Each vane 34 is twisted and oriented such that when viewed from a direction perpendicular to the axis of rotation of the pipe portion 16, the angle between the vane 34 and a plane 35 perpendicular to the axis of rotation varies between 36° and 55°. However, it will be understood that other vane configurations and orientations are envisaged. An alternative rotation imparting device 37 is shown in
Figure 5. The rotation imparting device 37 is similar to the rotation imparting device 24 shown in Figure 1, except that the rotation imparting device 37 does not include a central hub 32. Like and similar features are indicated with like reference numerals. It is expected that the rotation imparting device 24 shown in Figure 4 will generate more rotational force than the rotation imparting
device 37 shown in Figure 5 since with the rotation imparting device shown in Figure 4, the central hub 32 directs flowing water onto the vanes 34 during use. It will be understood that each vanes 34 is configured such that the vane 34 does not extend entirely around a central axis of the pipe portion 16, and in this example 4 adjacently disposed vanes 34 are provided around the central axis of the pipe portion 16.
Operatively associated with the pipe portion 16 is an alternator 36 having a rotor 38 fixed to an outer surface of the pipe portion 16 and a stator 40 disposed over and adjacent to the rotor 38. In this example, the alternator 36 is of brushless type and the arrangement is such that rotation of the pipe portion 16 about a longitudinal axis of the pipe portion 16 causes the rotor 38 to also rotate and thereby the alternator 36 to generate electricity at the stator 40. Generated electricity may be extracted through an output cable 42.
It will be appreciated that the electricity generating device 10 may be used to convert kinetic energy associated with water flowing through the pipe portion 16 to
electrical energy, and the converted energy for example may be used in the building thereby increasing the energy efficiency of the building as a whole. In this way, the electricity generating device may form part of an
electricity generating system, for example incorporated in a building, with the system including a plurality of electricity generating devices 10 arranged to generate electricity for use in the building.
As shown in Figure 2, instead of or in addition bolts 23, the pipe portion 16 may be securely disposed between the inlet and outlet pipe sections 12, 14 using a casing 44 that may include a hinge to allow the casing to be
disposed over the pipe sections 12, 14 without difficulty. The casing 44 may include annular seals 46 in order to provide a good seal between the casing 44 and the inlet and outlet pipe sections 12, 14, and fixing clamps (not shown) .
As shown more particularly in Figure 3, in this example, the pipe portion 16 includes first and second separable pipe sections 50, 52 that are engageable with each other and with the alternator 36 by disposing the alternator 36 between the pipe sections 50, 52 on a sleeve 54 and receiving the first and second pipe sections 50, 52 in the sleeve 54. This permits the pipe portion 16 to engage with the rotor 38. Each of the first and second pipe sections 50, 52 is provided with an annular flange 56 that abuts the rotor 38 when the first and second pipe sections 50, 52 are connected together.
A further embodiment of an electricity generating device 58 is shown in Figure 6. Like and similar features are indicated with like reference numerals. The rotation imparting device 24 in Figure 6 is shown diagrammatically .
The functionality of the electricity generating device 58 shown in Figure 6 is the same as the electricity
generating device 10 shown in Figure 1, in that flow of fluid interacts with a rotation imparting device to cause a pipe portion to rotate and thereby an alternator to generate electricity. However, with this embodiment, first and second bypass valves 60, 62 and a bypass pipe 64 are included. The first bypass valve 60 is disposed between the inlet pipe section 12 and the pipe portion 16, and includes a first actuator 64 disposable in a first position as shown in Figure 6 wherein water is able to flow from the inlet pipe section 12 to the pipe portion 16 but is not able to flow from the inlet pipe section 12 to the bypass pipe 64, and a second position wherein water is
able to flow from the inlet pipe section 12 to the bypass pipe 64 but is not able to flow from the inlet pipe section 12 to the pipe portion 16. Similarly, the second bypass valve 62 is disposed between the outlet pipe section 14 and the pipe portion 16, and includes a second actuator 66 disposable in a first position as shown in Figure 6 wherein water is able to flow from the pipe portion 16 to the outlet pipe section 14 but is not able to flow from the bypass pipe 64 to the outlet pipe section 14, and a second position wherein water is able to flow from the bypass pipe 64 to the outlet pipe section 14 but is not able to flow from the pipe portion 16 to the outlet pipe section 14. It will be understood that the bypass valves 60, 62 and the bypass pipe 64 may be used to divert water flow around the electricity generating device 10, for example so that maintenance may be carried out on the electricity
generating device 10 or the electricity generating device 10 replaced.
A further embodiment of an electricity generating device 70 is shown in Figures 7 to 9. Like and similar features are indicated with like reference numerals.
The electricity generating device 70 includes an
alternator 72 having a stator 74 and a rotor 76 receivable in the stator 74 and arranged to rotate relative to the stator 74.
The rotor 76 is hollow and is provided with a rotation imparting device 78, in this example in the form of vanes 78, that serves to cause the rotor 76 to rotate during use when fluid passes through the rotor 76 from an inlet at a first side of the rotor to an outlet at an opposite second side of the rotor 76.
In this example, the rotation imparting device 78 is integral with a pipe portion 80 having a generally
cylindrical pipe section 82 and a flange 84 at one end of the pipe section 82. The pipe portion 80 is engageable with the rotor 76 by receiving the pipe section 82 through the rotor 76. In this example, the pipe portion 80 and the rotation imparting device 78 are integrally formed. The pipe portion 80 may be formed of steel or any other suitable material.
However, it will be understood that other arrangements are possible. For example, the pipe portion may be omitted and the rotation imparting device 78 may be integrally formed with the rotor 76.
A variation of the device 70 shown in Figures 7 to 9 is shown in Figure 10. The electricity generating device shown in Figure 10 includes a rotation imparting device 24 of the type shown in Figure 4
In this example, the vanes 34 of the rotation imparting device 24 are fixed to the central hub 32 and attached to an internal wall of the pipe portion 80. In this way, rotation of the central hub 32 and vanes 34 in response to flow of liquid through the device 70 causes rotation of the pipe portion 80 and thereby rotation of the rotor 76 relative to the stator 74.
In this example, each vane is connected to the central hub such that fluid is still able to pass between the blade or vane and the central hub, for example by connecting each blade or vane to the central hub at a spot connection such that only a relatively small connection exists between the vane and the central hub 32.
With the embodiments shown in Figures 7 to 10, each end of
the pipe portion 80 is attached to a spacer 86 and
bearings 88, each bearing being received in a respective channel 90 formed in a bearing support flange 92 attached to the stator 74, as shown more particularly in Figure 10. The bearings 88 and spacers 86 may be fixed to the rotor 76 using any suitable fixing device, for example bolts 94. Similarly, the bearing support flanges 92 may be fixed to the stator 74 using any suitable fixing device, for example bolts 96. In this example, 4 such channel type bearings are disposed at each end of the rotor 76.
It will be understood that the bearings 88 and associated bearing support flanges 92 serve to locate the rotor 76 relative to the stator 74 and enable the rotor 76 to rotate inside the stator 74.
The alternator 72 is attached to first and second pipe sections 81, 83 at fixing flanges 87, 89, and the first and second pipe sections 81, 83 are connected to inlet and outlet pipes 91, 93.
It will be appreciated that the embodiments shown in
Figures 7 to 10 are relatively compact and the operative components of the electricity generating device are completely encased, with the only moving part being the rotor 76.
It will also be appreciated that with the embodiments shown in Figures 7 to 10, the rotor is submerged in the fluid flow and, accordingly, in this embodiment, magnets of the rotor are attached to a supporting rotor structure using water proof material, such as silicone.
The power generated by an electricity generating device according to the device shown in Figure 10 was measured for various flow rates of water through the device and the results are shown in the table below.
Water flow rate (L/s) Power (W)
115 411
139 630
151 800
163 1001
180 1208
195 1422
The diameter of the pipe portion 80 was 150mm, the speed of rotation of the rotor was 360rpm, and the velocity of water through the pipe portion 80 was 11.04m/s.
For a water flow rate of 195L/s, 1422W of power was produced and the pressure head of the water flowing through the device was 15m. The pressure drop across the device was 147kPa.
It will be appreciated that in addition to generation of electricity, the device 10, 70 may be used to controllably reduce pressure in a fluid system, such as a water pipe network. For example, a typical water main pipe has a fluid pressure of about lOOOkPa and a typical fluid pressure at a building incoming water pipe is about
440kPa. The present device 10, 70 may therefore serve as a fluid pressure reducing device to reduce water main pressure as required for a building inlet pipe whilst at the same time generating electricity for use by the building. The amount of pressure reduction may be
controlled by appropriate configuration of the components of the device 10, 70, for example by modifying the
characteristics of the rotation imparting device, the size of the pipe portion 80, and so on, and/or by controlling the electrical power output from the device.
A further embodiment of an electricity generating device 110 is shown in Figure 11. The electricity generation
device 110 is for use in a body of water such as a river or a tidal body of water such as an ocean or sea.
The device 110 includes water directing devices 112 that serve to guide water towards an alternator 114 disposed between the water directing devices 112. The alternator 114 is of a similar type to the alternators 36, 72, that is, an alternator of the type having a stator and a hollow rotor provided with a rotation imparting device that serves to effect rotation of the rotor relative to the stator as water flows through the hollow rotor.
Each of the water directing devices 112 comprises a funnel member 116 connected to a first or second side of the alternator 114, and a filter member 118 that serves to permit water to flow to the alternator 114, but prevent matter greater than a defined size from passing through to the alternator 114. During use, the electricity generating device 110 is anchored to a bed of a body of moving water, in this example a bed 120 of a tidal ocean or sea. The anchoring arrangement includes a central plinth 122 fixed to the sea bed 120 in any suitable way, and side plinths 124. The central and side plinths 122, 124 may be formed of any suitably strong water tolerant material, such as concrete.
The side plinths are attached to the central plinth 122 using suitable tethers 123, for example formed of carbon fibre or steel wire material. The alternator 114 sits on a column 126, for example formed of concrete material, extending from the central plinth 122. The column may be secured to the central plinth 122 using suitable tethers for example formed of carbon fibre or steel wire material. It will be understood that during installation of the electricity generating device 110, the device 110 would be oriented on the sea bed 120 such that the funnel members
116 substantially align with the expected direction of water movement indicated by arrow A, in this example due to tidal water flows. During use, water moves relative to the electricity generating device 110 as a result of tidal flows and some of the water is directed towards the alternator 114 by the funnel members 116 and flows through the hollow rotor of the alternator. As a consequence of interaction between the flowing water and the rotation imparting device in the rotor, the rotor is caused to rotate and the alternator thereby generates electricity.
A cross-sectional view of an example alternator 116 is shown in Figure 12. The alternator 116 in this example connects to each funnel member 116 using a flange member 130 that is fixed to the alternator 116, for example using bolts 132. The alternator 116 is similar to the alternator 72 shown in Figure 10 and like and similar features are indicated with like reference numerals.
With the alternator shown in Figure 12, a modified
rotation imparting device 134 is provided because during use water will flow in both directions according to tidal water movements. The modified rotation imparting device 134 includes a hub portion 136 provided with 2 oppositely facing convex end profiles, each of which intermittently faces water flow during use.
An alternative version of an electricity generating device 140 for use submerged in a body of water is shown in
Figure 13. Like and similar features are indicated with like reference numerals.
The electricity generating device 140 is mounted during
use on a river bed 142 and therefore, unlike the tidal flow conditions experienced by the device 110 shown in Figures 11 and 12, water flow will be in one direction only. As a consequence, only 1 water directing device 112 is required.
It will be understood that during installation of the electricity generating device 140, the device 140 would be oriented on the river bed 142 such that the funnel member 116 faces the expected water flow indicated by arrow B.
In this example, the diameter of the alternator is approximately 4m, although it will be understood that any suitable size is envisaged.
A further embodiment of an electricity generating device 140 is shown in Figures 14 to 17.
The electricity generating device 140 is similar to the electricity generating devices shown in Figures 7 to 10 and like and similar features are indicated with like reference numerals.
However, with the electricity generating device 140 shown in Figures 14 to 17, instead of providing channel type bearings 88, the shaft 28 on which the central hub 32 is mounted is attached at longitudinal ends to first and second bearings 142, 144 each mounted centrally of a rim 146 and spoke 148 support arrangement.
The rim 146 and spoke 148 arrangement is spaced from the stator 74 such that one of the rim 146 and spoke 148 arrangements can be disposed between the first pipe section 81 and the outlet pipe 93, and the other of the rim 146 and spoke 148 arrangements can be disposed between the second pipe section 83 and the inlet pipe 91, in order to securely rotatably support the rotor 76 and rotation
imparting device disposed internally of the rotor.
In this example, the first bearing 142, intended to be disposed upstream, is a thrust type bearing and the second bearing 144, intended to be disposed downstream, is a roller type bearing. However, it will be understood that other arrangements are possible. For example, if the device 140 is intended to be used with water flowing in both directions, both first and second bearings 142, 144 may be thrust type bearings.
In this embodiment, the central hub 32 is connected to the blades or vanes 78 and the blades or vanes 78 are
connected to the pipe portion 80.
It will be appreciated that while the above embodiments are described in relation to an electricity generating device, the device 10, 70, 110, 140 may alternatively be used to pump fluid by supplying the alternator with electricity. In doing so, the alternator can be arranged to function as a motor, whereby the hollow rotor and the rotation imparting device rotate and thereby pump liquid through the rotor. In this way, the rotation imparting device functions as a fluid movement imparting device. It will be understood that the direction of fluid flow through the rotor may be controlled by applying
appropriate electrical voltages to the stator of the alternator . Modifications and variations as would be apparent to a skilled addressee are deemed to be within the scope of the present invention.