Wave Energy Generator with Positive Buoyancy Reaction Member

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Solution Overview

Problem

Existing wave energy converters face challenges in reliably harnessing wave power over the long term due to instability in highly energetic sea conditions, leading to costly over-engineering and variable stability, which is limited by the mass and size of the reaction member.

Innovation Solution

The generator incorporates positive buoyancy in both the reaction member and the energy capturing float, with adjustable depth setting means and flexible mooring lines to enhance stability, allowing for reduced size and mass of the reaction member while maintaining stability, particularly in energetic sea states.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the reaction member remains on the sea surface continuously to capture wave energy, then energy capture capability is improved, but the structure is subject to high loads in storm conditions requiring costly over-engineering

Engineering Contradiction:
Improveenergy capture capabilityVSAvoidstructural strength
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The reaction member is pre-positioned at an optimal depth below the sea surface before wave energy capture begins. This preliminary positioning allows the system to avoid surface-level storm impacts while maintaining energy capture capability through the connecting rod mechanism, eliminating the need for costly over-engineering.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The connecting rod acts as an intermediary element between the submerged reaction member and the surface float. It transmits wave energy forces from the surface to the submerged reaction member, enabling energy capture without exposing the main structure to direct storm loads at the surface.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Stability of the object's composition

If the mass of the reaction member is increased to improve stability, then stability is improved, but the size and cost of the device increases

Engineering Contradiction:
Improvestability of reaction memberVSAvoidmass of reaction member
Core Design Contradiction:
Stability of the object's compositionVSQuantity of substance

Solution Approach 1:

The system uses the buoyant force of water as a counterweight to the gravitational force on the reaction member. By positioning the reaction member at an optimal depth where hydrostatic pressure provides natural stabilization, the system achieves stability without requiring excessive mass, thereby reducing device size and cost.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

Solution Approach 2:

The invention replaces the traditional mechanical stability approach (increasing mass) with a hydrodynamic stability approach. The optimal depth positioning utilizes water pressure and buoyancy forces to stabilize the reaction member, substituting mechanical mass with fluid mechanical effects.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Object-affected harmful factors

If the reaction member is positioned deeper in the water to reduce surface wave impact, then protection from surface loads is improved, but the distance to the energy capturing float increases requiring longer connection means

Engineering Contradiction:
Improveprotection from surface wave loadsVSAvoidlength of connection means
Core Design Contradiction:
Object-affected harmful factorsVSLength of stationary object

Solution Approach 1:

The connecting rod is designed as a dynamic element that can adjust its length and orientation based on wave conditions and reaction member depth. This dynamic capability allows the system to optimize the balance between protecting the reaction member from surface loads and maintaining an efficient energy transmission path, avoiding the need for excessively long rigid connections.

Inventive Principle:
Principle #15Dynamics

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This design improves stability and reduces the size and mass of the reaction member, enabling more efficient energy conversion and optimal performance in harsh sea conditions by transferring reaction forces to the seabed, thus enhancing the generator's ability to convert wave motion into usable energy.

Implementation Method 1

The generator has positive buoyancy in both the reaction member and the energy capturing float to increase the stability of the reaction member

Methodology Applied
Scientific EffectBuoyancy: Archimedes' Principle (Buoyancy)

Data Source

PatentEP3645864B1Wave powered generator
Publication Date: 2021.08.04 MARINE POWER SYST
  • EP3645864B1 patent drawingFigure 1
  • EP3645864B1 patent drawingFigure 2
  • EP3645864B1 patent drawingFigure 3

AI summary

A generator for capturing and converting wave energy into a more useful form is provided. The generator comprises: at least one energy capturing float (2) which is movable in response to wave motion; a reaction member (1) to be positioned below the energy capturing float; connecting lines (5a, 5b, 5c, 5d) for connecting the at least one energy capturing float to the reaction member and defining a spacing (D2) between the energy capturing float and the reaction member; energy convertors (6a, 6b, 6c, 6d) for converting relative movement between the reaction member and at least one respective energy capturing float to useful energy. The generator includes depth setting means such as adjustable mooring lines (3a, 3b, 3c, 3d) securing the reaction member to the sea bed SB for setting the depth (D1) of the reaction member in the sea. Both the float and the reaction member possess a positive buoyancy, allowing suitable tension to be applied to the mooring lines. The improved tension brought about by the net positive buoyancy has the surprising effect of improved stability in energetic sea conditions.