Near-field Thermoradiative Device With Structured Heat Sink
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Solution Overview
Problem
Thermoradiative (TR) devices are inefficient due to a large mismatch between the bandgap frequency of TR cells and the surface plasmon resonant frequency of typical metallic heat sinks, leading to low power generation performance when harvesting low-grade waste heat.
Innovation Solution
The design incorporates a structured heat sink with nanostructured patterns that introduce additional surface resonance modes closer to the TR cell's bandgap energy, enabling better impedance matching and enhanced near-field radiative energy transfer, using metallic materials like zirconium carbide or tungsten as heat sinks, and additional layered materials to support resonant modes on the TR cell side.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a metallic heat sink with surface plasmon resonance is used, then heat dissipation performance is improved, but the resonance frequency mismatch with TR cell bandgap causes low power generation efficiency
Solution Approach 1:
The patent modifies the resonant frequency parameter of the heat sink by introducing periodic grating structures. This structural modification creates additional resonant modes at lower frequencies that match the TR cell bandgap, resolving the frequency mismatch while preserving the metallic material's superior thermal conductivity for heat dissipation.
Solution Approach 2:
The patent employs composite structures combining metallic materials with periodic grating patterns. The metallic base provides thermal conductivity for heat dissipation, while the grating structure introduces resonant modes at frequencies matching the TR cell bandgap, achieving both efficient heat dissipation and resonant coupling for power generation.
2Productivity
If selective radiation at narrow band is achieved through nanophotonic approaches, then conversion efficiency is improved, but radiation power is greatly suppressed
Solution Approach 1:
The patent utilizes resonant coupling between the TR cell and the grating-structured heat sink, analogous to resonant vibration. The periodic structure creates resonant modes that enhance the radiative energy transfer at specific frequencies, allowing both high conversion efficiency and sufficient radiation power through resonant amplification.
3Temperature
If typical noble metals are used as heat sink, then thermal conductivity is improved, but surface plasmon resonance frequency is much higher than TR cell bandgap energy
Solution Approach 1:
The patent changes the effective resonant frequency parameter of the metallic heat sink by introducing periodic grating structures. This structural modification lowers the resonant frequency from the high surface plasmon resonance to frequencies matching the TR cell bandgap, while preserving the metallic material's high thermal conductivity.
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 configuration significantly boosts the output power density and conversion efficiency of TR cells, achieving higher power generation compared to traditional designs by optimizing resonant coupling and heat dissipation.
Implementation Method 1
Thermoradiative (TR) cells have been proposed as heat engines to convert heat into electricity
Implementation Method 2
the first surface is separated from the bottom surface with a distance d to establish near-field resonance between the bottom surface and the structured surface
Implementation Method 3
a thermal conductive element having a first surface and a second surface
Data Source
AI summary
A thermoradiative device for generating power includes a thermoradiative element having a top surface and a bottom surface, wherein the thermoradiative element is a semiconductor material having a bandgap energy Eg. The device includes a thermal conductive element having a first surface and a second surface, wherein the first surface is arranged to face the bottom surface of the thermoradiative element, and the first surface is a structured surface having a periodic structure, wherein the structured surface is separated from the bottom surface with a distance d to establish near-field resonance between the bottom surface and the structured surface. The device further includes supporters configured to bond the thermoradiative element and the thermal conductive element.