Thermoelectric Energy Extraction with Closed-Loop Fluid Circulation

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Solution Overview

Problem

Current thermal energy harvesting and storage systems are inefficient in capturing and converting thermal energy into electricity, with photovoltaic systems only absorbing 20% of sunlight and converting it at 10-15% efficiency, and existing thermoelectric systems not providing continuous energy supply.

Innovation Solution

A thermal energy to electrical energy extraction system comprising a thermoelectric converter, electric conditioner, measuring means, and controller, with a closed loop pumping and circulation system to create a continuous temperature gradient across the thermoelectric converter, allowing thermal energy conversion into electricity both during and after solar energy supply.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If photovoltaic systems are used to capture solar energy, then electrical energy can be generated, but the conversion efficiency is only 10-15% and only 20% of sunlight is absorbed

Engineering Contradiction:
Improveenergy conversion efficiencyVSAvoidelectrical energy output
Core Design Contradiction:
Loss of energyVSProductivity

Solution Approach 1:

The patent replaces photovoltaic conversion with a thermal-mechanical-thermal conversion system. Solar energy is first converted to thermal energy via solar collectors heating a fluid, then stored thermally, and finally converted to electricity via thermoelectric generators. This substitution enables much higher overall efficiency by decoupling the energy capture and conversion processes.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system utilizes phase transitions of the thermal conducting fluid (heating to high temperature, cooling during discharge) to enable efficient thermal energy storage and transfer. The fluid cycles between hot and cold states, absorbing and releasing thermal energy effectively.

Inventive Principle:
Principle #36Phase transitions

2Duration of action of stationary object

If thermal energy is stored for continuous supply, then electricity can be generated during solar absence, but existing systems do not provide continuous energy supply

Engineering Contradiction:
Improvecontinuous energy supply durationVSAvoidcontinuous electricity generation
Core Design Contradiction:
Duration of action of stationary objectVSReliability

Solution Approach 1:

The system maintains continuous useful action by circulating the thermal conducting fluid continuously through the solar collector, storage tank, and thermoelectric generator. During sunlight hours, the fluid is heated and stores thermal energy; during darkness, the stored thermal energy is released, maintaining a continuous temperature gradient and electricity generation across the thermoelectric converter.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The system performs preliminary action by storing thermal energy in the storage tank during the day before it is needed. The thermal conducting fluid pre-heats and stores energy in advance, so that when solar energy is absent, the pre-stored thermal energy immediately continues to drive the thermoelectric generator without interruption.

Inventive Principle:
Principle #10Preliminary action

3Duration of action of stationary object

If expensive battery systems are used for energy storage, then continuous electricity supply can be achieved, but system cost increases

Engineering Contradiction:
Improveenergy storage durationVSAvoidsystem cost
Core Design Contradiction:
Duration of action of stationary objectVSEase of manufacture

Solution Approach 1:

The patent replaces expensive, complex battery systems with a simpler, cheaper thermal storage system using a thermal conducting fluid and storage tank. The thermal energy storage medium is inexpensive compared to electrochemical batteries, and the system achieves the same continuous supply function through thermal rather than electrical storage.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The thermal conducting fluid acts as an intermediary between the solar collector and the thermoelectric generator. Instead of directly converting solar energy to electricity with batteries for storage, the fluid mediates by carrying and storing thermal energy, enabling continuous operation at lower cost.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 a high conversion efficiency of 60% with continuous electricity supply, utilizing a thermoelectric converter, DC to DC converter, and microprocessor-controlled conditioning to optimize energy extraction and storage, eliminating the need for expensive battery systems.

Implementation Method 1

The Seebeck effect entails that when there is a difference in temperature between two dissimilar electrical conductor or semiconductor substances, there will be a resulting electric potential difference (or Voltage difference) between the two substances

Methodology Applied
Scientific EffectSeebeck effect: Seebeck Effect

Implementation Method 2

Photo voltaic solar electricity generators are not capable of capturing all of the energy contained in sunlight, with some sources stating that only about 20 percent is absorbed

Methodology Applied
Scientific EffectSolar energy absorption: Absorption (EM radiation)

Implementation Method 3

a closed loop pumping and circulation system comprising a thermal exchanger system which is configured to allow flow of thermal conducting fluid from the solar collector towards the thermal storage tank during solar energy supply, thereby transferring thermal energy collected by the solar collector to the thermal energy storage tank

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 4

a closed loop pumping and circulation system comprising a thermal exchanger system

Methodology Applied
Scientific EffectPumping: Pump

Data Source

PatentEP3539163B1Thermal energy to electrical energy extraction system
Publication Date: 2023.08.02 UNIVERSITY OF SOUTH AFRICA
  • EP3539163B1 patent drawingFigure 1~2
  • EP3539163B1 patent drawingFigure 3
  • EP3539163B1 patent drawingFigure 4~5

AI summary

A thermal energy to electrical energy extraction system which includes: a thermoelectric converter, for converting thermal energy into electrical energy, the thermoelectric convertor being connectable to a thermal energy source; an electric conditioner connectable to the thermoelectric converter for conditioning the electric energy output of the thermoelectric converter and generating a conditioned electrical output; a measuring means for measuring the electric energy within the system; and a controller for controlling the thermoelectric converter in order to vary the conditioned electrical output based on the measurements obtained from the measuring means.