Submerged OTEC Fluid Loop for Storm-Resistant Power

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Solution Overview

Problem

Conventional Ocean Thermal Energy Conversion (OTEC) systems face inefficiencies and practical limitations for small-scale power generation due to mechanical and thermal losses associated with pumping cold water from deep depths, and existing remote ocean power generation methods are vulnerable to harsh weather and damage in high-latitude regions.

Innovation Solution

A method utilizing a closed loop Rankine cycle that moves a working fluid between two ocean depths or between air and water temperatures to generate electricity, with the power generated stored in a battery to drive the cycle, allowing for efficient low-power generation and mobility, and optionally powering AUVs or research platforms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If conventional OTEC systems pump cold ocean water from deep depths to the surface for cooling, then the condensation function is achieved, but mechanical and thermal losses increase significantly

Engineering Contradiction:
Improvemechanical and thermal lossesVSAvoidpracticality for small-scale power generation
Core Design Contradiction:
Loss of energyVSEase of operation

Solution Approach 1:

Instead of pumping cold water from deep depths to the surface for condensation, the patent inverts the approach by pumping warm surface water down to depth for evaporation. This eliminates the need to pump large quantities of cold water upward, thereby reducing mechanical and thermal losses while enabling practical small-scale power generation.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent extracts the essential function of cold water pumping from the system by utilizing the natural density difference between warm and cold water. The cold water at depth rises naturally to the surface after serving its cooling purpose, eliminating the need for continuous pumping of cold water and reducing energy losses.

Inventive Principle:
Principle #2Taking out (Extraction)

2Duration of action of moving object

If remote ocean power stations use battery power, then portability and mobility are achieved, but lifetime and power generation capacity are limited

Engineering Contradiction:
ImprovelifetimeVSAvoidpower generation capacity
Core Design Contradiction:
Duration of action of moving objectVSPower

Solution Approach 1:

The system generates its own power through the ocean thermal gradient, using the temperature difference between warm surface water and cold deep water to drive the thermodynamic cycle. This self-powered operation eliminates battery limitations, enabling continuous operation and extended lifetime without sacrificing power generation capacity.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent utilizes the natural temperature parameter variation with ocean depth to generate power. By exploiting the temperature gradient between surface and deep water, the system converts thermal energy into mechanical work, providing sustained power generation capacity that overcomes battery limitations.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If floating buoys use solar photovoltaics or wave energy, then renewable power generation is achieved, but vulnerability to storm damage and collisions increases

Engineering Contradiction:
Improveprotection from storm damage and collisionsVSAvoidoperation in harsh high-latitude weather conditions
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

Instead of exposing equipment at the surface where it is vulnerable to storms and collisions, the patent submerges the power generation system below the surface. The warm water intake and processing occur at depth, protecting the equipment while still utilizing the ocean thermal gradient for power generation in harsh conditions.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent employs a flexible, collapsible structure that can withstand deep-sea pressure and harsh environmental conditions. The flexible design allows the system to operate reliably at depth while protecting internal components from external damage, enabling operation in high-latitude and storm-prone regions.

Inventive Principle:
Principle #30Flexible shells and thin films

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 efficient, self-sufficient, and mobile electricity production with reduced equipment mass, capable of generating significantly more power than previous designs while avoiding damage from surface storms and collisions, and can operate in harsh weather conditions.

Implementation Method 1

The water at the second depth has a greater temperature than the water at the first depth such that the enclosed working fluid transitions between a liquid phase at the first depth and a vapor phase at the second depth

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

The water at the second depth has a greater temperature than the water at the first depth such that the enclosed working fluid transitions between a liquid phase at the first depth and a vapor phase at the second depth

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 3

Compressing an enclosed working fluid at a first depth of a body of water to cause the enclosed working fluid to ascend to a second depth

Methodology Applied
Scientific EffectBuoyancy: Archimedes' Principle (Buoyancy)

Data Source

PatentEP3535492B1Environmental thermal energy conversion
Publication Date: 2024.06.12 SEATREC INC
  • EP3535492B1 patent drawingFigure 1
  • EP3535492B1 patent drawingFigure 2
  • EP3535492B1 patent drawingFigure 3

AI summary

A method of electricity production using water thermal energy includes compressing an enclosed working fluid at a first vertical position relative to a surface of a body of water to cause the fluid to move to a second vertical position relative to the surface and subsequently move to the first position in a closed loop, an external environment at the second position having a greater temperature than an external environment at the first position such that the fluid transitions between a liquid phase at the first position and a vapor phase at the second position, the compressing using power from a battery, and expanding the fluid at the second position to generate electricity to charge the battery. The first and second positions may be two depths of the body of water or a height of an atmosphere above the body of water and a depth of the body of water.