Compressed-Air Energy Storage for Constant-Pressure Turbine Output
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Solution Overview
Problem
Conventional wave power plants with Wells turbines suffer from low energy efficiency, inconsistent energy output, frequent component failures due to varying wave sizes and speeds, and lack of black-start capability, necessitating electrical energy for initiation.
Innovation Solution
The system employs Pelton turbines operating at a constant pressure, independent of wave size or frequency, with a closed-loop mechanism using a working fluid and gas pressure to maintain continuous energy supply, enabling black-start capability without grid energy and utilizing water turbines with high efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If Wells turbines with symmetrical blades are used to handle bidirectional airflow from waves, then the turbine can rotate in specific direction regardless of flow direction, but the efficiency is significantly lower than turbines with asymmetrical blades
Solution Approach 1:
The system divides the wave energy conversion process into separate compression and expansion phases using distinct pneumatic chambers. The compression chamber handles incoming wave pressure while the expansion chamber drives the turbine, allowing the turbine to operate with unidirectional flow optimized for efficiency rather than bidirectional flow requiring symmetrical blades
Solution Approach 2:
Compressed air acts as an intermediary medium between the wave energy and the turbine. Waves compress air in the compression chamber, storing energy, which then expands through the turbine in the expansion chamber to generate electricity. This intermediary allows the turbine to operate efficiently with controlled unidirectional flow while the wave energy is converted through the compression-expansion cycle
2Power
If Wells turbines are used in conventional wave power plants, then the system can convert pressure change into electrical energy, but the system lacks self-start capability and black-start capability requiring external electrical energy
Solution Approach 1:
The system uses gravity and wave action itself to initiate the compression cycle. When waves enter the compression chamber, they naturally compress the air without requiring external power. The pressure differential created by wave motion automatically drives the compression and expansion cycles, enabling the system to start and operate autonomously without external electrical energy or motor assistance
3Productivity
If the system operates directly with varying wave sizes and speeds, then it can respond to wave energy availability, but enormous stress is placed on moving components causing frequent failures requiring substantial safety margins
Solution Approach 1:
The pneumatic chambers and compressors are designed with substantial safety margins and pressure relief mechanisms to withstand peak wave forces before they can damage the turbine components. The compression chamber acts as a buffer that absorbs the variable wave energy and converts it to controlled pneumatic pressure, protecting the turbine from direct mechanical stress of varying wave sizes and speeds
Solution Approach 2:
The system uses energy storage in the form of compressed air to maintain continuous turbine operation despite the discontinuous and variable nature of wave energy. The compression chamber stores energy during high-wave periods and releases it during low-wave periods, ensuring the turbine receives continuous controlled flow and operates smoothly without experiencing the stress of direct wave variability
4Loss of time
If conventional wave power plants store energy in flywheels to compensate for wave unevenness, then short-term energy storage is achieved, but the design becomes complex and energy efficiency deteriorates
Solution Approach 1:
The system uses pneumatic pressure storage instead of mechanical flywheels to store energy. Compressed air in the compression chamber serves as the energy storage medium, replacing complex mechanical energy storage systems with simpler pneumatic storage that integrates naturally with the wave-to-pressure conversion process
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
The system achieves continuous energy supply, high turbine efficiency (up to 92%), reduced stress on components, and the ability to start without external energy, allowing for quasi-continuous energy generation and stable frequency output.
Implementation Method 1
a compression chamber (28) in which a compression fluid (50) can flow in and out, thereby compressing a working gas (26)
Implementation Method 2
a turbine unit (6, 7, 8) comprising at least one turbine (9) and at least one generator, wherein the at least one turbine (9) is designed to be driven by the working gas (26) expanding at a substantially constant pressure
Implementation Method 3
The at least one liquid container (2, 3, 4) is filled with a working fluid (51), wherein the working fluid (51) can be transferred from the at least one liquid container (2, 3, 4) to the compression chamber (28) through the turbine unit (6, 7, 8)
Data Source
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AI summary
A system for storing and recovering energy which comprises: - at least one liquid vessel for storing a working liquid, and - a turbine unit for power generation, wherein the turbine unit is connected to the liquid vessel in such a way and is designed in such a way that the working liquid can be conveyed out of the liquid vessel and through the turbine unit by way of the action of a working gas on the working liquid, and in the process drives the turbine unit for the purpose of power generation, and - a working gas provision unit for providing the working gas, in particular compressed air, at a substantially constant working gas pressure, wherein the working gas provision unit is connected to the liquid vessel in such a way that the working gas acts at said constant working gas pressure from above on the liquid surface of the working liquid in the liquid vessel and, as a consequence, conveys the working liquid through the turbine unit, wherein the working gas provision unit comprises: - a compression vessel which is configured for the compression of working gas situated therein, by way of compression liquid which can flow into said compression vessel, and - a pressure accumulator which is connected thereto by means of a first one-way valve and is configured to store the compressed working gas at an accumulator gas pressure which is higher than the working gas pressure, wherein the one-way valve is configured in such a way as to enable an overflow of the compressed working gas only in one direction from the compression vessel into the pressure accumulator if the pressure of the compressed working gas is higher than the accumulator gas pressure.