AU2013101419A4 - Medow Sea Wave Energy Converter (SWEC) - Google Patents

Abstract

A Sea Wave Energy Converter (SWEC) including: a semi submerged floating concrete structure (1) with an internal chamber, openings at top and bottom produced with lightweight concrete, with foam cores, and significant floatation foam pockets; opening (2) in base of structure to allow ingress / egress of sea water; a DC generator unit (3) coupled to a hydraulic turbine unit (6) with automatic adjustable pitch blades via a solid shaft (4); mooring lines -tension Leg (4); floatation pockets with injected foam (5). Figure 1 - SWEC Still water level Floatation Floatation

Description

1 Description [0001] The invention is a Sea Wave Energy Converter (SWEC), including all necessary systems in order to convert ocean wave energy into electrical energy. [0002] A SWEC, which can be described as, a semi submerged oscillating water column (OWC) style device, with a hydraulic power takeoff. The invention incorporates hydraulically gearing a flow of seawater, available due to the constant equalization of differential pressures between the water levels inside and outside the floating device as the wave passes the structure, acting on an inline hydraulic turbine, with adjustable pitch to ensure single rotational direction of shaft, coupled to a generator. [0003] Similar to a conventional floating OWC device, the structure is open at the base to accept seawater, as a wave passes the structure it attempts to equalize the water level inside the device with that of the wave. Unlike existing OWC's the innovation seeks to utilize the low head flow experienced through the underwater opening via a turbine chamber and into the structures internal chamber. [0004] The WEC platform is designed with a height and mooring tension specific to the site conditions, pulled down by taught mooring lines in a tension leg arrangement. The platform is sufficiently tall and contains sufficient buoyancy, low enough in its structure, to maintain tension on mooring lines at the lowest peak of the waves trough at the lowest tide, essentially mimicking a hard moored / piled device which has no vertical movement. [0005] The structure does not rise and fall with a passing wave and so the interaction experienced by the structure is limited to a flow in and out of the device. As the structure is fixed, there is no concern for managing phase shift between the structure and the wave environment to ensure energy is available for capture. [0006] Power take off is in the form of a hydraulic turbine located near the base opening of the structure. The velocity of flow is increased through the inlet & turbine chamber being substantially smaller in diameter than that of the internal chamber. A larger volume of water must pass the propeller in an attempt to equalize the water level of the larger internal volume of the chamber. [0007] The hydraulic turbine, depending on design capacity, is prescribed as one of several existing simple low head hydro turbine technologies. Experimentation is being conducted on a bespoke low head adjustable blade propeller to accept the sinusoidal like flow whilst operating the drive shaft in a single direction of rotation. [0008] A permanent magnet DC generator is housed in the top of the structure, coupled to the turbine via a solid drive shaft. DC => AC inverter is also incorporated to prepare the output power for grid / other utility connection.

2 Description of Figure 1: The general view of the SWEC is illustrated in Figure 1 and includes the following: 1. Semi submerged floating Concrete Structure, with internal chamber, openings at top and bottom. Produced with lightweight concrete, with foam cores, and significant floatation foam pockets. 2. Opening in base of structure to allow ingress / egress of sea water 3. DC Generator Unit coupled to turbine via solid shaft 4. Moring Lines - Tension Leg 5. Floatation pockets with injected foam 6. Hydraulic Turbine unit with automatic adjustable pitch blades

Claims (3)

1. A floating semi submersed oscillating water column (OWC) style Sea Wave Energy Converter (SWEC) platform integrating one or more water column units with direct hydraulic power take off.

2. Incorporating flow velocity gearing through internal volume and inlet diameter specification.

3. Incorporating a by-directional hydraulic turbine maintaining single direction of rotation.