Thermophotovoltaic Cells with Electric Field for Continuous Power
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Solution Overview
Problem
Long-duration, high-altitude airships require continuous power, but existing solar-powered systems are inefficient due to the intermittent nature of solar radiation and rely on heavy, complex, and unreliable energy storage solutions, while current photovoltaic cells cannot harness the continuous blackbody radiation from Earth for power generation.
Innovation Solution
Development of thermophotovoltaic (TPV) materials and systems that utilize an electric field to broaden the frequency range sensitivity, enabling the conversion of Earth's blackbody radiation into electrical power, including the use of quantum dots and piezoelectric materials to generate and apply an electric field, thereby enhancing the efficiency of TPV cells to approach the Landsberg Limit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If solar cells are used to provide power for airships, then electrical power can be generated during the day, but power cannot be provided continuously at night and heavy energy storage systems are required
Solution Approach 1:
The patent changes the spectral response parameters of photovoltaic cells to detect lower frequency infrared radiation from Earth's blackbody radiation. By modifying the bandgap energy of the semiconductor material and applying electric fields to adjust carrier separation efficiency, the system can convert thermal radiation into electrical power continuously, eliminating the day-night cycle limitation of traditional solar cells.
Solution Approach 2:
The patent replaces the mechanical/chemical energy storage systems (batteries, fuel cells) with a direct energy conversion system that transforms thermal radiation into electrical power through thermophotovoltaic effect. This substitution eliminates the need for heavy storage mechanisms while providing continuous power generation.
2Duration of action of moving object
If energy storage systems are added to solar-powered airships, then nighttime power can be provided, but the systems become heavy, complex, and unreliable
Solution Approach 1:
The patent extracts and eliminates the energy storage subsystem from the power system by implementing continuous thermophotovoltaic power generation. The TPV cells directly convert Earth's infrared radiation into electrical power around the clock, removing the need for batteries, fuel cells, or other storage mechanisms that add weight and complexity.
Solution Approach 2:
The patent enables the airship to harvest energy directly from Earth's blackbody radiation, which is continuously available at the airship's altitude. The system serves itself by converting the ambient thermal environment into electrical power, eliminating the need for external fuel storage or complex energy management systems.
3Power
If traditional photovoltaic cells are used, then electrical power can be generated from sunlight, but they cannot harness long wavelength infrared radiation for power generation
Solution Approach 1:
The patent fundamentally changes the spectral response parameters of photovoltaic cells by using semiconductor materials with smaller bandgap energies and applying electric fields to optimize carrier separation. These parameter changes enable the detection and conversion of long wavelength infrared photons (8-40 microns) that traditional silicon cells cannot utilize, expanding the usable spectrum to include Earth's blackbody radiation.
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 TPV system can generate continuous electrical power from Earth's blackbody radiation, reducing the need for solar cells and energy storage, providing a reliable and efficient power source for airships, even during nighttime and high wind conditions, with potential applications in various devices for energy recycling and waste heat conversion.
Implementation Method 1
a TPV system includes a heat source, a photon converter, and a TPV cell. The photon converter (e.g., 'selective emitter'), through physical (or radiant) contact with the heat source, gains energy, and then re-emits that energy in the form of photons of a selected frequency. These photons are then transmitted to an adjacent solid-state TPV generator and converted into electrical energy.
Implementation Method 2
The strength of the electric field is sufficient to shift the sensitivity of the TPV material to sense lower frequency radiation than the TPV material can sense when the electric field is not applied, thereby substantially broadening the range of frequencies that can be utilized by the TPV material.
Implementation Method 3
the use of quantum dots and piezoelectric materials to generate and apply an electric field, thereby enhancing the efficiency of TPV cells to approach the Landsberg Limit.
Implementation Method 4
Quantum Dots (QDs) are very small semiconductor structures (of the order of nanometers or somewhat larger in diameter) surrounded by a material of a wider bandgap so that the ensemble can be utilized as a TPV cell. QDs confine electrons and holes in three spatial dimensions and to a very small number of energy levels, depending on their size.
Implementation Method 5
Photon converters (of which selective emitters are a subset) absorb photons over a broad range of energies and emit them over a designer-selected narrow band of energy, conserving energy and entropy so as to comply with the First and Second Laws of Thermodynamics.
Data Source
AI summary
An apparatus includes a thermo-photovoltaic (TPV) material that is capable of generating electrical power from low temperature heat radiation. An electric field generator is coupled to apply an electric field to the TPV material. The strength of the electric field is sufficient to shift the sensitivity of the TPV material to sense lower frequency radiation than the TPV material can sense when the electric field is not applied and to broaden the band of frequencies over which the TPV is effective.