OTEC Cold Water Pipe Domed Intake and Winch Retention System

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Solution Overview

Problem

Ocean Thermal Energy Conversion (OTEC) power plants face low thermodynamic efficiency, high parasitic loads, and environmental concerns due to the large volume of nutrient-rich cold water intake and discharge, which limits their commercial viability and environmental impact.

Innovation Solution

A floating, multi-stage heat engine OTEC power plant with a structurally integrated cold and warm water conduit system, featuring a minimal heave platform and offset staved cold water pipe design, reduces construction and operating costs, enhances efficiency, and minimizes environmental impact through efficient heat exchange and controlled water discharge.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If large volume of cold water is drawn from deep ocean to achieve maximum heat transfer, then heat exchange efficiency is improved, but parasitic load and energy consumption increase

Engineering Contradiction:
Improveheat exchange efficiencyVSAvoidparasitic load
Core Design Contradiction:
Loss of energyVSUse of energy by moving object

Solution Approach 1:

The patent utilizes natural ocean currents and density-driven flow to move cold water from depth to the surface without requiring high-power pumps. The cold water intake system leverages hydraulic principles where the density difference between cold deep water and warm surface water creates natural flow, reducing the energy required for water circulation while maintaining effective heat transfer.

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The patent changes the flow rate parameter of cold water to optimize the balance between heat transfer efficiency and energy consumption. By adjusting the cold water flow rate to match natural ocean current velocities, the system achieves effective cooling without the excessive energy input required by traditional high-velocity pump systems.

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If long cold water intake pipe is used to reach deep ocean water, then cold water supply is improved, but construction cost and structural complexity increase

Engineering Contradiction:
Improvecold water supplyVSAvoidstructural complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The cold water intake system is divided into multiple modular pipe sections that can be assembled in segments rather than requiring a single long continuous pipe. This segmentation reduces manufacturing complexity, facilitates easier installation and maintenance, and allows the system to be configured in modular units that can be scaled according to power plant requirements.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cold water intake pipe structure is designed to serve multiple functions: it not only transports cold water but also provides structural support for the floating platform, acts as a mooring element, and can be configured to accommodate different operational depths. This multi-functionality reduces the need for separate structural components, thereby lowering overall system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Loss of energy

If large diameter cold water pipe is used to transport sufficient cold water volume, then heat transfer capability is improved, but material cost and manufacturing difficulty increase

Engineering Contradiction:
Improveheat transfer capabilityVSAvoidmanufacturing difficulty
Core Design Contradiction:
Loss of energyVSEase of manufacture

Solution Approach 1:

The large diameter cold water pipe is constructed from multiple smaller pipe sections joined together using standardized coupling mechanisms. This segmentation allows each section to be manufactured using conventional piping techniques rather than requiring fabrication of a single large-diameter pipe, significantly reducing manufacturing difficulty and material cost while maintaining the required overall diameter for sufficient water volume transport.

Inventive Principle:
Principle #1Segmentation

4Stability of the object's composition

If floating platform is used to minimize heave motion, then operational stability is improved, but platform construction cost and complexity increase

Engineering Contradiction:
Improveoperational stabilityVSAvoidplatform construction
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The floating platform design merges the cold water intake structure with the platform support structure, where the cold water pipes are integrated into the platform's structural framework rather than being separate attachments. This integration reduces the number of independent components, simplifies construction, and lowers overall system complexity while maintaining the platform's stability characteristics.

Inventive Principle:
Principle #5Merging (Combining)

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 solution improves overall efficiency, reduces parasitic loads, lowers construction and operating costs, and minimizes environmental impact by optimizing heat transfer and water management, making OTEC power plants more commercially viable and environmentally friendly.

Implementation Method 1

a cold water pipe floating vertically in the ocean from near the surface to a depth of between 2,000 ft and 4,000 ft or more

Methodology Applied
Scientific EffectBuoyancy: Archimedes' Principle (Buoyancy)

Implementation Method 2

The OTEC process uses the temperature difference between surface and deep sea tropical waters to drive a heat engine to produce electrical energy

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Data Source

PatentEP2758663B1Ocean thermal energy conversion power plant cold water pipe connection
Publication Date: 2017.06.21 ABELL FOUNDATION INC
  • EP2758663B1 patent drawingFigure 1
  • EP2758663B1 patent drawingFigure 2
  • EP2758663B1 patent drawingFigure 3

AI summary

An offshore structure for use with an OTEC system includes a submerged spar having a lower portion having a cold water intake. The cold water intake includes a domed terminus in fluid communication with a cold water pipe. A dry machinery space adjacent the cold water intake includes one or more cold water supply pumps and one or more cold water pipe lifting and retention winches having a lifting cable connected to the cold water pipe.