Deformable Membrane Maintains Sub-Micron Gap in Thermal Photovoltaic Systems
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Solution Overview
Problem
Micron-gap thermal photovoltaic systems face challenges in maintaining a stable sub-micron gap between the hot and cold surfaces due to thermal effects, leading to deformation and uncontrollable variances in power output, which limits the efficiency and practicality of converting heat to electricity.
Innovation Solution
A vacuum-tight shell with a liquid-cooled mechanical assembly that uses a deformable metal foil membrane and pneumatic diaphragm to maintain a uniform sub-micron gap between the emitter and photovoltaic cells, allowing for thermal expansion and efficient heat transfer while preventing heat conduction across the gap.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the gap between the hot and cold surfaces is reduced to sub-micron spacing to increase power transfer, then the power density increases by approximately an order of magnitude, but thermal effects induce cupping, warping, or deformation resulting in uncontrollable variances in power output
Solution Approach 1:
The patent introduces a deformable membrane as an intermediary element between the hot and cold surfaces. This membrane actively maintains the sub-micron gap spacing by deforming in response to thermal effects, thereby mediating the interaction between the two surfaces and preventing direct contact while maintaining the enhanced power transfer of sub-micron spacing.
Solution Approach 2:
The patent employs a dynamic, deformable membrane rather than a rigid spacer to maintain the gap. The membrane's ability to dynamically adjust its shape in response to thermal expansion and contraction allows the system to maintain stable sub-micron spacing despite temperature variations, transforming a static spacing problem into a dynamically controlled solution.
2Power
If the temperature is increased to compensate for lower power density in prior art devices, then the power output increases, but the temperature is limited by the material of the device and system components
Solution Approach 1:
The patent skips the conventional approach of increasing temperature to boost power output and instead directly implements sub-micron gap spacing to achieve high power density at lower temperatures. This allows the system to bypass material temperature limitations while still achieving high power output through enhanced near-field coupling.
3Manufacturing precision
If a rigid structure is used to maintain gap spacing, then the manufacturing precision can be achieved, but the structure cannot accommodate thermal expansion and deformation
Solution Approach 1:
The patent replaces rigid gap-maintaining structures with a flexible deformable membrane. This thin film structure can elastically deform to accommodate thermal expansion and contraction while maintaining the sub-micron gap spacing, thereby combining the benefits of manufacturing precision with thermal adaptability.
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 design enhances energy transfer by maintaining a consistent sub-micron gap, increasing power density and reducing the operating temperature, making the system more efficient, cost-effective, and practical for high-temperature applications like industrial melting furnaces.
Implementation Method 1
Thermo photovoltaic devices (TPV) consist of a heated black-body which radiates electromagnetic energy across a gap onto a photovoltaic device which converts radiant power into electrical power
Implementation Method 2
a heated black-body which radiates electromagnetic energy across a gap
Implementation Method 3
The photovoltaic cell will generally have to be cooled somewhat so that it will function properly
Implementation Method 4
liquid-cooled mechanical assembly
Data Source
AI summary
The present invention relates to micron-gap thermal photovoltaic (MTPV) technology for the solid-state conversion of heat to electricity. The problem is forming and then maintaining the close spacing between two bodies at a sub-micron gap in order to maintain enhanced performance. While it is possible to obtain the sub-micron gap spacing, the thermal effects on the hot and cold surfaces induce cupping, warping, or deformation of the elements resulting in variations in gap spacing thereby resulting in uncontrollable variances in the power output. A major aspect of the design is to allow for intimate contact of the emitter chips to the shell inside surface, so that there is good heat transfer. The photovoltaic cells are pushed outward against the emitter chips in order to press them against the inner wall. A high temperature thermal interface material improves the heat transfer between the shell inner surface and the emitter chip.