Pitch-Driven Wave Energy Converter Counterweight Mechanism
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Solution Overview
Problem
Existing wave energy converter (WEC) technologies are inefficient in wave climates with short-period waves, as they rely on springs to counteract gravitational forces, which are unsuitable for heavy reaction masses and limit their application to small power systems.
Innovation Solution
The pitch-driven WEC technology eliminates the need for springs by using reaction masses at opposite ends of a container, connected via linkages to function as counterbalances, capturing energy from pitch and roll motions without gravitational springs, allowing for efficient energy harvesting in short-period wave environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If springs are used to counteract gravitational forces in MOSWEC technology, then the reaction masses can oscillate at frequency near predominant wave frequency, but the system is limited to relatively small power autonomous WEC applications because known physical springs are not satisfactory for very heavy reaction masses
Solution Approach 1:
The patent uses a counterweight mechanism where a second reaction mass is positioned to balance the first reaction mass. When one mass moves downward, the other moves upward, creating a balanced system that eliminates the need for gravitational springs. This counterweight approach allows the system to handle very heavy masses (a thousand kilograms or more) while maintaining oscillatory motion near predominant wave frequency.
Solution Approach 2:
The patent extracts and eliminates the gravitational spring component from the MOSWEC system. By removing the need for springs to counteract gravity, the system can be scaled to utility-level power applications without being constrained by the limitations of physical springs for heavy masses.
2Productivity
If heave responsive WEC systems are used, then they are most efficient in highly energetic wave climates with high-amplitude, long-period waves, but they are comparatively inefficient in wave climates with short period waves
Solution Approach 1:
The patent implements a dynamic pitch-driven mechanism where the reaction masses are free to oscillate and the container is designed to respond to wave-induced pitching motions. This dynamic system can adapt to different wave periods, making it efficient in both long-period and short-period wave climates, unlike fixed heave-responsive systems.
Solution Approach 2:
The pitch-driven WEC device is designed to be universally applicable across different wave climates. By responding to pitch motions rather than being limited to heave motions, the system can effectively harvest energy from both long-period high-amplitude waves and short-period low-amplitude waves, expanding its adaptability to various ocean environments.
3Power
If reaction masses are made very heavy (a thousand kilograms or more) in MOSWEC technology, then the system can generate more power, but known physical springs are not satisfactory to counteract gravitational forces
Solution Approach 1:
The patent employs a counterweight system where heavy reaction masses are balanced by positioning another mass in opposition. This arrangement allows very heavy masses (1000 kg or more) to be used for power generation without requiring gravitational springs, thereby maintaining system reliability while achieving utility-level power output.
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 approach enables highly efficient and cost-effective energy capture from short-period waves, making it suitable for utility-scale applications and wave farms, while eliminating the need for springs, thus overcoming limitations of prior art technologies.
Implementation Method 1
The two reaction masses are interconnected to function so as to counterbalance each other, whereby when one reaction mass is driven in an upward direction the other reaction mass is driven down, in the opposite direction
Data Source
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AI summary
A wave energy converter (WEC) buoy includes at least one pitch-driven WEC ("PDWEC") device. Each PDWEC device includes two reaction masses which are placed at diametrically opposite ends of a container designed to float along the surface of a body of water and to move In response to the pitching motion of the waves. The reaction masses are interconnected so that when one reaction mass moves up, the diametrically opposed reaction mass moves down, and vice-versa. The movement of the reaction masses drives power take off (PTO) devices to produce useful energy. The reaction masses may be interconnected by any suitable linking system. One or more PDWEC device may be combined with a heave responsive device to produce a WEC buoy which can produce a power output in response to pitch or heave motion.