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Title:
FLOATING POWER PLANT
Document Type and Number:
WIPO Patent Application WO/1997/047876
Kind Code:
A1
Abstract:
A floating power plant, comprising a floating body (2) having an underside (10) designed for contact with a body of water, side walls (3), water turbines (6, 7) located in the floating body (2), generators (60) connected to the water turbines and ducts (22, 23, 24, 50, 51, 52, 53) for carrying the water past the water turbines (6, 7). The power plant is equipped with a skirt (11) which projects below the underside (10) of the floating body (2) and accommodates a plurality of outflow ducts. These ducts (24) extend laterally and convergently from the underside (10) of the floating body (2) towards one of the side walls (3), past at least one respective water turbine (7). The turbine is located at or near the smallest cross section of the outflow duct (24). Water is led via the duct (24) from the underside (10) of the floating body (2) sideways past the turbine (7) to the outside of the floating body (2) when the floating body (2) moves downwards relative to the body of water.

Inventors:
Fred, Olsen
Oigarden, Hans
Application Number:
PCT/NO1997/000081
Publication Date:
December 18, 1997
Filing Date:
March 21, 1997
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
Fred, Olsen
Oigarden, Hans
International Classes:
B63B39/00; B63B39/08; E02B3/06; (IPC1-7): F03B13/22; F03B13/12
Foreign References:
US4447740A
US3965364A
US3870893A
Other References:
DERWENT'S ABSTRACT, No. 87-305568/43, Week 8743; & SU,A,1 300 188 (EVTROPKOV V M), 30 March 1987.
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Claims:
P a t e n t c l a i m s
1. A floating power plant, comprising a floating body (2) having an underside (10) designed for contact with a body of water, side walls (3), water turbines (6, 7) located in the floating body (2), generators (60) connected to the water turbines and ducts (22, 23, 24, 50, 51, 52, 53) for carrying the water past the water turbines (6, 7), characterised in that the power plant comprises a skirt (1 1) which projects below the underside (10) of the floating body (2) and accommodates a plurality of outflow ducts (24), each of which extends laterally and convergently from the underside (10) of the floating body (2) towards one of the side walls (3), past at least one respective water turbine (7), which turbine is located at or near the smallest crosssection of the outflow duct (24), in order to lead water from the underside (10) of the floating body (2) sideways past the turbine (7) to the outside of the floating body (2) when the floating body (2) moves downwards relative to the body of water.
2. A power plant according to Claim 1, characterised in that the outflow ducts (24) converge both in the vertical direction and in the horizontal direction, so that the outlet openings (41) of the outflow ducts (24) are spaced apart, thus allowing first portions to be formed between the outlet openings (41 ) of the outflow ducts (24), in which first portions there are formed inlet openings (30, 26) for inflow ducts (22, 23), which inflow ducts (22, 23) in turn converge in the opposite direction of the outflow ducts (24) and have outlet openings (25) which are spaced apart, so that second portions are formed between the outlet openings (25) of the inflow ducts (22, 23), in which second portions the inlet openings of the outflow ducts (24) are formed, and that outside the inlet openings (30, 26) of the inflow ducts (22, 23) there are provided guide means (8, 9) to guide the water in through the inlet openings (30, 26) of the inflow ducts (22, 23) and past a water turbine (6) when the floating body (2) moves upwards.
3. A power plant according to Claim 1 or 2, characterised in that the underside of the floating body (2) is generally planar and defines the upper limit of the outflow ducts (22, 23) and the inflow ducts (24).
4. 4A power plant according to any of the preceding claims, characterised in that it comprises a plurality of first downflow ducts (50, 52) which extend from an opening (56, 57) in the side (3) of the floating body and down to a water turbine (6, 7) located in the floating body (2), that outside the inlet openings (56, 57) of the downflow ducts (50, 52) there are provided guide means (5) to guide the water in through the inlet openings (56, 57) when the floating body (2) moves downwards, and that the draught of the floating body (2) is adapted so that the inlet openings (56, 57) in the main are under water.*& 5.
5. A power plant according to any of the preceding claims, characterised in that it comprises a plurality of second downflow ducts (51, 53) which extend from an opening (54, 55) in the side (3) of the floating body (2) and down to a water turbine (6, 7) located in the floating body (2), that outside the inlet openings of the downflow ducts (51 , 53) there are provided guide means (4) to guide the water in through the inlet openings (51, 53) when the floating body (2) moves downwards, and that the draught of the floating body (2) is adapted so that the inlet openings (51, 53) in the main are under water.*& 6.
6. A power plant according to any of the preceding claims, characterised in that the turbines (6, 7) are arranged every other turbine (7) close to the side wall (3) of the floating body (2) and every other turbine (6) at a distance from the side wall (3) of the floating body (2), that the turbines (7) close to the side wall (3) of the floating body (2) receive water from the outflow ducts (24), a first set (52) of the first downflow ducts (50, 52) and a first set (53) of the second downflow ducts (51, 53), and that the turbines (7) at a distance from the side wall (3) of the floating body receive water from the inflow ducts (22, 23), a second set (50) of the first downflow ducts (50, 52) and a second set (51) of the second downflow ducts (51 , 53).
7. A power plant according to any one of the preceding claims, characterised in that the inflow ducts (23, 23) are divided into a first inflow duct (22) and a second inflow duct (23), that the first inflow duct is provided with guide means (8) to guide the water in through the first inflow duct (22) when the floating body (2) moves upwards, and that the second inflow duct (23) is provided with guide means (9) to guide the water in through the second inflow duct (23) when the floating body (2) moves downwards. *& 8.
8. A power plant according to any one of the preceding claims, characterised in that outside the outlet openings (41 ) of the outflow ducts (24) there are provided guide means (42, 45) in order to change the direction of the effluent water and lead the water in through one of the inflow ducts (22, 23).*& 9.
9. A power plant according to Claim 8, characterised in that the guide means for the effluent water comprise an inclined wall (45) and a curved plate (42).*& 10.
10. A power plant according to any one of the preceding claims, characterised in that the guide means for guiding the water into the downflow ducts (50, 51 , 52, 53) and the inflow ducts (22, 23), respectively, comprise inclined plates which are interlaced with one another so that an upward facing and a downward facing channel are formed which are not in direct fluid communication with each other.
Description:
FLOATING POWER PLANT

The present invention relates to a floating power plant, comprising a floating body having an underside designed for contact with water, water turbines located in the floating body, generators connected to the water turbines and ducts to carry water past the water turbines.

Over the years many attempts have been made to exploit wave motion in seawater to produce unusable energy. Some examples of earlier attempts are:

US-3.870,893, which teaches a floating power plant having a concave underside, wherein water is forced from the concave underside up through a duct, in which there is located a turbine, and flows out again via side ports. This solution will, however, exhibit very little efficiency, since the water that is forced up through the duct will always have to flow in one direction. If the water flows in the opposite direction, the turbine will rotate in the opposite direction. This will happen quite frequently as the water in the duct has a pumping effect as long as the top of the duct is higher than the troughs of the waves outside the floating power plant. As taught in the patent, the top of the duct is above the water in static water, which it must be if the water is to run out of the power plant again. This means that the solution cannot make use of overpressure in the duct, and thus nor can it generate any power to speak of.

GB-1 581 831 , which teaches a power plant comprising a plurality of upper side ports and a plurality of lower side ports. Here, the intention is that the water should run in through the upper side ports and down to the lower side ports via a turbine. This solution will function if the floating structure is out of phase with the waves, that is only when the waves are regular. When the waves are non-regular, the basin located above the turbine will not be emptied completely and the water flow will come to a stop; likewise the production of energy.

SE-463 430. which teaches a power plant comprising an inclining plane leading up to a basin, from the lower end of which water flows out via an ejector. Here, the intention is that the ejector should draw with it water from a duct leading from the underside of the

power plant. This solution is however primarily intended for the recovery of minerals from seawater, and for this purpose comprises a sorbent chamber. Here, however, the wave energy harnessed is from the crests of the waves, which move up an inclining plane. The energy produced will be minimal, as what has been forgotten in this case is the counter-pressure of the sea, which will mean very little, if any, water will flow from the underside of the power plant up to the ejector.

NO- 178 164, which also teaches a power plant where the intention is to harness the energy in the crests of the waves by allowing these to move up an inclining plane. The water is then captured up in a plurality of ducts which are brought together to form a collecting pipe, wherein there is located a power converting device. Here too, it is only the energy in the crests of the waves that is harnessed in a conventional manner per se.

DE-2 648 318, which teaches another variant where the crests of the waves are collected in a basin having ducts leading down to turbines. The turbines are driven because there exists a difference in level between the basin and the sea, which results in the water in the basin having a tendency to flow downwards. This power plant also harnesses solely the energy in the crests of the waves, and will not function particularly efficiently, if at all, below a certain wave height.

DK-0766/94, which teaches a solution that is also based on pressure differences which are built by waves washing up an inclining plane, in the same way as waves travel up a beach. Here, turbines are located at an opposite inclining plane, which extends from the top of the first-mentioned plane. The turbines capture water which breaks over the top of the inclined planes. This solution will also only function reasonably efficiently above a certain wave height.

DE-2 923 212, which teaches a solution where the ebb and flow of the tide drive a floating body, which functions as a pump that blows air on two propellers. This has nothing to do with wave power, and will probably function very inadequately in any case.

DE-2 324 994, which also teaches a solution where the principle of waves breaking over an inclined plane is utilised. However, the inclined plane is equipped with check valves, so that water is also captured even if the waves do not break over the top of the inclined plane. However, the generation of energy is conditional upon wave activity above a certain level.

DE-1 940 126 teaches a power plant which is located on the seabed and exploits pressure differences created by tidal ebb and flow. Wave energy is not harnessed in this case.

GB-2 175 962 teaches a power plant where the motion of waves is utilised to create movement in an air column, which in turn drives a turbine. Loss of energy on the transfer of the energy in the waves to movement of an air flow is inevitable.

FR-2 530 738 teaches yet another variant of a power plant which is based on the movement of wave crests up an inclined plane. Here, the power plant will not produce energy when wave activity is below a certain level.

NO-151 479 teaches a power plant, where water flows past a turbine located in a vertical pipe, because of the vertical component of motion of the waves. This produces an oscillating movement of the water, which results in the turbine blades having to be turned in order for the turbine to maintain its direction of rotation. This is very complicated, and results in erratic running of the turbine.

The objective of the present invention is to harness major parts of the energy in wave motion in a rational and efficient manner. The present invention breaks with the tradition of utilising the motion of the wave crests, and is based instead on utilising motion which is induced in a floating body owing to the motion of the waves. When it is done in this way, the energy which is supplied to a floating body both when it moves upwards relative to the seabed and when it moves downwards relative to the seabed can be harnessed. Moreover, the power plant will produce energy even when there is very little wave activity.

The major aspects of the invention are disclosed in the characterising clause of claim 1 below. The subsequent dependent claims disclose additional aspects of the invention and advantageous embodiments.

The invention will be described in more detail below with reference to the appended drawings, wherein:

Figure 1 is a schematic illustration of a power plant according to the invention;

Figure 2 is a perspective view of a section of the floating power plant;

Figure 3 shows the section in Figure 2 in perspective from a different angle;

Figure 4 shows the section in Figure 2 in perspective from another angle;

Figure 5 shows the section in Figures 2 to 4 from yet another angle and with some of the parts removed to illustrate the internal structure;

Figure 6 shows the section in Figure 5, where parts of the channels have been removed to show the internal structure of the channels;

Figure 7 shows a section through the floating power plant, seen from above;

Figure 8 shows a vertical section where some of the water flow paths in the power plant are shown;

Figure 9 shows a second vertical section where other flow paths are illustrated;

Figure 10 shows a vertical section where additional flow paths are illustrated;

Figure 1 1 show a vertical section where yet more flow paths are illustrated.

Figure 1 shows a floating power plant 1 , comprising a floating body 2. On the side walls 3 of the floating body 2 there are provided channels 4, which extend approximately horizontally and are open upwards. These will be referred to hereinafter as upward facing channels 4. There are also provided channels 5, which run approximately horizontally and are open downwards. These will be referred to hereinafter as downward facing channels 5. These channels 4, 5 are connected via respective openings to ducts 50, 51 , 52, 53 which run down to a plurality of turbines 6, 7. Furthermore, the floating body is equipped with a skirt 1 1 at the edge of the underside 10, in which skirt 1 1 there are formed upward facing channels 8 and downward facing channels 9. These channels are in communication with an area below the underside 10 of the floating body 2 via ducts 22, 23, 24.

On top of the floating body 2 there may be provided inclined planes 12, 13 in order, in a conventional manner, to lead wave crests past a turbine 14. The power plant 1 may also be equipped with one or more windmills 15.

Figures 2, 3 and 4 show a section of the power plant I in perspective, seen from three different angles. Figures 5 and 6 show a corresponding section from other angles where the side wall 3 has been removed in both figures, and the freely outward projecting inclined planes of the channels 4, 5, 8 and 9 have been removed in Figure 5, whereas the channels 4, 5, 8 and 9 have been removed in their entirety in Figure 6, so that the structure is easier to see. Below reference is made to all of Figures 2 to 6, as all the figures taken together give a good picture of the structure of the section.

These figures illustrate the upper upward facing channel 4. the upper downward facing channel 5, the lower upward facing channel 8, the lower downward facing channel 9 and the turbines 7. The upper upward facing channels 4 are in direct communication with ducts 51a, 51b, etc. and 53a, 53b, etc. via a respective opening 54a, 54b, etc. and 55a, 55b, etc., which ducts extend down to a respective inner turbine wheel 6a, 6b, etc. and an outer turbine wheel 7a, 7b, etc. All water that is captured by the upper upward facing channel 4 is thus led down to the turbine wheels 6, 7 via ducts 51a, 51b, etc. and 53a, 53b, etc.

Like the channel 4, the upper downward facing channel 5 is also in communication with a respective duct 50a. 50b, etc. and 52a, 52b, etc. via a respective opening 56a, 56b, etc. and 57a, 57b, etc. The ducts 50a, 50b, etc. and 52a, 52b, etc. extend down towards a respective inner turbine wheel 6a, 6b, etc. and an outer turbine wheel 7a, 7b etc., and meet a respective duct 50, 53 close to the turbine wheel 6, 7. The openings 56a, 56b, etc. and 57a, 57b, etc. are placed alternately with the openings 54a, 54b, etc. and 55a, 55b, etc., so that the channel 4 is equipped with a whole wall portion 16a, 16b etc., opposite the openings 56a, 56b, etc. and 57a, 57b, etc. Similarly, the channel 5 is equipped with a whole wall portion 21a, 21b, etc., opposite the openings 54a, 54b etc. and 55a, 55b, etc. All water captured by the upper downward facing channel 5 is thus led into the ducts 50, 52. The ducts 51, 53 and 50, 52 are converging in order to help increase the flow rate of the water which flows down through these ducts.

From the inner turbine wheels 6a, 6b etc., the water flows out through openings 25a, 25b, etc. to the underside 10 of the floating body 2. From the outer turbine wheels, the

water flows out through a duct section 27, and here strikes a curved plate 42 and an inclined wall 45. This will be described in more detail below.

The turbine wheels 6, 7 are placed alternately 6a, 6b etc. close to the side wall 3 of the floating body 2, and alternately 7a, 7b a small distance from the side wall 3 of the floating body. In the bottom edge of the floating body 2, there are formed a lower upward facing channel 8 and a lower downward facing channel 9. The channel 8 is, via openings 30a, 30b, etc., in communication with a respective duct 22a, 22b, etc., which extends past a respective turbine wheel 6a, 6b (sec Figure 5).

The lower channel 9 is in communication with ducts 23a. 23b etc. via a respective opening 26a, 26b, etc., which ducts 23a, 23b, etc. extend past the turbine wheel 6a, 6b, etc. where they in fact meet with ducts 22a, 22b, etc. (see Figure 5). The openings 23a, 23b, etc. are placed alternately with the openings 30, 30b, etc. so that there is provided a wall portion 48a, 48b, etc. between the openings 26a, 26b, etc. and a wall portion 49a, 49b, etc. between the openings 30, 30b, etc.

The ducts 24a, 24b extend from an area below the underside 10 of the floating body 2 past a respective turbine wheel 7a, 7b and out through an opening 41a, 41b (see Figure 5), in order to lead water from the underside of the floating body 2 past the turbine wheel 7a, 7b, when the floating body 2 moves downwards, thereby causing a local pressure increase in the water which is immediately below the bottom 10. At the outlet of the opening 41a, 41b, there is provided a curved plate 42a, 42b (see Figure 6) which prevents the water from flowing out in the channel 8 via the openings 30a, 30b, etc. The duct 22a, 22b etc. here is equipped with an inclined wall 45a, 45b, etc. (see Figure 5). The water is forced with the aid of the curved plate 42a, 42b, etc. and the inclined wall 45a, 45b, etc. sideways (see the arrows 43a, 43b, etc., in Figure 7), downwards and towards the left, seen from outside the floating body, and in through the ducts 22a, 22b, etc. At the corners of the floating body 2, the water will however be forced towards the right and into the duct 23d, see the arrow 43e in Figure 7. When the movement of the floating body turns and it starts its movement upwards, the water which flows in through the openings 30a, 30b, etc. from the downward facing channel 8 will help to force the water flowing out from the openings 41a, 41b, etc. into the ducts 22a, 22b, etc.

All the ducts 22a, 22b, etc., 23a, 23b, etc. and 24a, 24b converge in towards their respective turbine wheel, and the turbine wheel 6, 7 is located at the part of the duct 22a,

22b, etc., 23a, 23b, etc. and 24a, 24b, etc. which is smallest in cross-section. The ducts are separated from each other by dividing walls 46a, 46b, etc. and 47a, 47b, etc.

Figure 7 shows a section through the floating body 2 on a level with the lower upward facing channels 8 and the turbines 7. Here, generators 60 connected to the turbine wheels 6, 7 can also be seen, which generators may be located in the vacant spaces in each corner of the floating body. Furthermore, ducts 22a, 22b, etc., 23a, 23b, etc. and 24a, 24b, etc. can be seen. The arrows 44a, 44b, etc. and 43a, 43b, etc. illustrate the direction of flow of the water through the ducts 24a, 24b, etc., when the floating body 2 moves downwards. The arrows 58a, 58b, etc. illustrate the direction of flow of the water through the ducts 22a, 22b, etc. when the floating body 2 moves upwards, whilst the arrows 59a, 59b, etc. illustrate the direction of flow of the water through the ducts 23a, 23b, etc. when the floating body moves downwards.

Figure 8 shows a section along the line VIII-VIII in Figures 6 and 7, and illustrates the water flow past the inner turbine wheels 6a, 6b, etc. when the floating body 2 moves downwards (the arrow 70) relative to the body of water. On such a movement of the floating body 2, the upper downward facing channel 5 captures water close to the side wall 3 of the floating body. The water flows via the opening 54 into a downwardly directed duct 51. The duct 51 has its outlet at the outer side of the inner turbine wheel 6. From here, the water flows in towards the underside 10 of the floating body 2 via a horizontal duct section 25. Water which is immediately outside and below the floating body 2 flows into the lower downward facing channel 9 and via an opening 26 into the duct 23. The duct 23 extends past the turbine wheel 6 at the bottom edge thereof and the water flows in towards the underside 10 of the floating body 2 via the duct section 25.

Figure 9 shows a section along the line IX-IX in Figures 6 and 7, and illustrates how the water flows past the outer turbine wheel 7 on the same downward movement (the arrow 70) of the floating body 2. Water which is immediately outside the side 3 of the floating body 2 flows into the channel 5 and via the opening 57 into the duct 52. The duct 52 opens out at the inside of the outer turbine wheel 7. From here, the water flows on the underside of the turbine wheel 7, through a duct section 27 and here strikes the curved plate 42 and the inclined wall 45 (not shown in Figure 9) and is forced, as described above, downwards, to the side and in towards the duct 22. Water which is on the underside 10 of the floating body 2, is, because of the downward movement of the underside 10. forced into a duct 24 and past the turbine wheel 7 on the underside

thereof. From here, the water flows via the duct section 27 and strikes the curved plate 42, and is forced to change direction downwards and to the side in the same way as the water which flowed down from the upper channel 5.

Figure 10 shows a section along the line X-X in Figures 6 and 7, and illustrates the water flow at the inner turbine wheel 7a when the floating body moves upwards (the arrow 71). Water which is on the outside of the side wall 3 of the floating body 2 above the upper upward facing channel 4 will be captured thereby, flow through the opening

54 and down in the duct 51. The duct 51 opens out, as mentioned previously, on the outer side of the inner turbine wheel 6. From here, the water flows around a part of the periphery of the turbine wheel 6 and via the duct section 25 to the underside 10 of the floating body 2.

Water which is immediately outside the side wall 3 of the floating body 2 and above the lower upward facing channel 8 will be captured thereby, flow though the opening 30 and into the duct 22. The duct 22 runs past the turbine wheel 6, and, after having passed the turbine wheel 6, the water flows through the duct section 25 to the underside 10 of the floating body 2.

Figure 1 1 shows a section along the line XI-XI in Figures 6 and 7 and illustrates the water flow at the outer turbine wheel 7 when the floating body moves upwards (the arrow 71). Water which is on the outside of the side wall 3 of the floating body 2 above the upper upward facing channel 4 will be captured thereby, flow through the opening

55 and down in the duct 53. The duct 53 opens out on the inside of the turbine wheel 7. After having passed the turbine wheel 7, the water flows through the duct section 24 to the underside 10 of the floating body 2.

Water which is above the channel 8 and immediately outside the side wall 3 of the floating body 2 will be captured by the channel 8, flow under the curved plate 42 and in through the opening 30 and the duct 22 to the inner turbine wheel 6 (see Fig. 10) Any water still flowing out of the opening 41 will also be forced into the duct 22.