Wave Energy Converter

Abstract

Apparatus (10) rests on the seabed at a location below sea level for capturing wave energy. The apparatus (10) comprises a body structure (11) having a diaphragm (25) adapted to deflect in response to wave action. A working chamber (27) is disposed immediately below the diaphragm (25) and contains a compressible fluid such as air. A pump system (43) is accommodated within the working chamber (27). The pump system (43) comprises two reciprocating pumps (45, 47) operating in opposition. The pumps (45, 47) are operably connected to the diaphragm (25) through a lever mechanism (61). Because of the geometry of the lever mechanism (61), the stroke length of each pump (45, 47) is less than the amplitude of displacement of the diaphragm (25) as it moves in response to wave action. Thus, the lever mechanism (61) increases the force acting on each pump (45, 47) by a given ratio and reduces the stroke of each pump by the same ratio. The reduction in stroke length provides for compact construction so that the pumps (45, 47) can be readily accommodated within the working chamber (27). The pumps (45, 47) draw seawater from the environment about the apparatus (10) and discharge the seawater at a high-pressure. The high-pressure seawater generated by the pumps can be piped to shore for use in any appropriate purpose.

Description

FIELD OF THE INVENTION [0001] This invention relates to apparatus for converting wave energy in a body of water into a form which can perform useful work. [0002] The invention has been devised particularly, although not necessarily solely, for harnessing wave energy and converting the harnessed energy to pressurised fluid for use in any appropriate way. The fluid may comprise water drawn from the body of water itself. Where the body of water comprises an ocean, seawater drawn from the ocean may be piped under high-pressure to shore and fed to a reverse osmosis desalination unit to yield fresh water. The salt water concentrate exiting the desalination unit, which is still at high-pressure, may be fed to a turbine and the shaft power used to generate electricity. BACKGROUND ART [0003] There have been many proposals for devices that seek to harness ocean wave energy but only a few of such devices are actually under sustained commercial development. All of the commercial devices, whethe...

AI Technical Summary

Benefits of technology

[0010] The lever increases the force acting on the pump by a given ratio and reduces the stroke by the same ratio so that the net work transferred to the pump is substantially unchanged (if mechanical losses are low).

[0011] One reason for utilising the lever mechanism and hence a shorter pump stroke is that the overall height of the apparatus can be reduced, thus lowering overall cost. A further reason is that a shorter stroke length may be advantageous in terms of pump design, particularly in relation to sealing issues, where high-pressure fluids are involved.

[0014] Pumps acting in opposition may serve to provide hydraulic resistance to movement of the diaphragm in both directions, thereby dampening fluctuations in such movement.

[0015] The or each lever may be of framed construction, which provides both vertical and lateral rigidity under load.

Problems solved by technology

There have been many proposals for devices that seek to harness ocean wave energy but only a few of such devices are actually under sustained commercial development.

The net result is increased capital cost and decreased reliability.

However, a pump with a relatively long stroke is not particularly conducive to compact design which may possibly be a requirement in certain applications.

Images