Kite Spar Tether Attachment for Wind Energy Extraction

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Solution Overview

Problem

Existing kite systems for wind energy extraction face inefficiencies in power generation due to the need for complex and costly modifications to reduce tether tension during retraction, which can increase the likelihood of component failure and reduce overall efficiency.

Innovation Solution

The integration of a rigid spar arrangement with a tether attachment point that allows controlled movement within a defined area through actuator mechanisms, enabling pitch and roll control without moving individual bridle lines, thereby optimizing kite position for high lift during power generation and low lift during retraction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If complex modifications are made to reduce tether tension during retraction, then retraction efficiency is improved, but device complexity and cost increase significantly

Engineering Contradiction:
Improveretraction efficiencyVSAvoidmodification complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The invention extracts the tension reduction function from complex mechanical modifications and relocates it to the aerodynamic design of the kite itself. By designing the kite with specific bridle line configurations and control surfaces, the tension reduction is achieved through aerodynamic forces rather than mechanical devices, thereby improving retraction efficiency without increasing device complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention introduces control surfaces and aerodynamic elements as intermediaries between the wind force and the tether. These intermediaries allow the kite to actively manage tether tension through aerodynamic means, providing a simpler alternative to complex mechanical tension reduction devices while maintaining high retraction efficiency.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If complex modifications are made to reduce tether tension during retraction, then retraction efficiency is improved, but reliability decreases due to increased component failure likelihood

Engineering Contradiction:
Improveretraction efficiencyVSAvoidcomponent reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The invention removes the need for complex mechanical tension reduction devices by extracting the tension management function and implementing it through the kite's aerodynamic structure. This reduction in mechanical components directly improves reliability by eliminating potential failure points while maintaining effective retraction performance.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The kite is designed to automatically manage its own tether tension through aerodynamic forces generated by its structure and control surfaces. This self-service mechanism eliminates the need for additional active components to manage tension, thereby improving reliability without sacrificing retraction efficiency.

Inventive Principle:
Principle #25Self-service

3Productivity

If the kite is kept near the centre of the wind for optimal power generation, then power generation efficiency is improved, but retraction becomes more difficult due to higher tether tension

Engineering Contradiction:
Improvepower generation efficiencyVSAvoidretraction energy requirement
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The invention implements dynamic control of the kite's orientation and bridle line configuration, allowing the system to optimize tether tension at different phases of operation. During power generation, the kite maintains optimal positioning near the center of the wind, while during retraction, the dynamic adjustment of control surfaces and bridle lines reduces tether tension, enabling efficient retrieval without compromising power generation efficiency.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes key parameters such as bridle line angles, control surface deflections, and kite orientation dynamically based on operational phase. These parameter changes allow the system to maintain optimal power generation conditions when needed while reducing tether tension during retraction, effectively decoupling the two conflicting requirements.

Inventive Principle:
Principle #35Parameter changes

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 solution enhances the controllability and stability of the kite, reducing energy requirements for retraction and maintaining flight stability, leading to improved power generation efficiency and reduced component stress.

Implementation Method 1

a wing (1) for providing lift

Methodology Applied
Scientific EffectLift: Aerofoil

Implementation Method 2

control of the kite in pitch or in pitch and roll combined, is achieved

Methodology Applied
Scientific EffectMechanical control: Mechanical Force

Data Source

PatentEP3218598B1A kite
Publication Date: 2021.11.03 KITEMILL AS
  • EP3218598B1 patent drawingFigure 1
  • EP3218598B1 patent drawingFigure 2
  • EP3218598B1 patent drawingFigure 3

AI summary

A kite for use in a system for extracting energy from the wind comprises: a wing (1) having a roll neutral point or zone when the kite is in flight; a tether (4) coupled directly or indirectly to the wing; a rigid spar arrangement (2); tensile couplings (3) from the spar arrangement to multiple locations on the wing; and an actuator linkage arrangement (6, 7, 10,11) having a length dimension that can be controllably adjusted. The spar arrangement has first and second attachments (8, 5) to the tether, at the first attachment (8) the spar arrangement is fixed to the tether at a location that is above a roll neutral point or zone of the wing, and at the second attachment (5) the spar arrangement is attached to the tether by the actuator arrangement (6, 7, 10, 11) at a location that is below the roll neutral point or zone of the wing.