Localized Solar Collector Structure for Efficient Steam Generation
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Solution Overview
Problem
Current solar energy harvesting systems, particularly photo-thermal applications, face low efficiency and require high sunlight concentrations, leading to complexity and cost, with significant heat loss through convection and inefficient thermal energy utilization.
Innovation Solution
A localized heating structure with a thermally insulating layer and expanded carbon structure, combined with a spectrally-selective solar absorber and evaporation wick, to concentrate solar energy and minimize heat dissipation, enhancing evaporation efficiency and thermal conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional surface-based solar collectors are used, then the system structure is simple, but the thermal efficiency is limited to around 52%
Solution Approach 1:
The patent employs a porous floating absorber structure that combines light-absorbing materials with porous substrates. This porous structure increases the surface area for solar absorption while maintaining buoyancy and structural simplicity, thereby improving thermal efficiency without significantly complicating the system architecture.
Solution Approach 2:
The invention uses composite material structures combining different functional layers including light-absorbing coatings, porous substrates, and thermal insulation materials. This composite approach enables simultaneous optimization of solar absorption, heat transfer, and structural properties, achieving over 52% thermal efficiency while keeping the overall system relatively simple.
2Loss of energy
If high optical concentration is used to improve efficiency, then the thermal conversion improves, but the system complexity and cost increase
Solution Approach 1:
The floating absorber structure utilizes the natural buoyancy and fluid dynamics of the system to achieve effective solar energy capture without requiring external optical concentration mechanisms. The system serves itself by leveraging the floating platform's inherent properties to concentrate and absorb solar energy directly, eliminating the need for complex mirrors, lenses, or tracking systems while maintaining high thermal conversion efficiency.
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 structure achieves a solar-thermal conversion efficiency of up to 85% at 10 kW/m², significantly improving steam generation and reducing the optical concentration required for phase-change, thus enhancing the efficiency of solar energy harvesting.
Implementation Method 1
a spectrally-selective solar absorber, configured to absorb incident solar radiation
Implementation Method 2
a thermally insulating layer, adjacent to the spectrally-selective solar absorber, having a thermal conductivity of less than about 0.1 W/(mK)
Implementation Method 3
an evaporation wick, disposed in one or more of the evaporation openings in the thermally insulating layer, configured to contact liquid and to allow the liquid to be transported
Implementation Method 4
one or more evaporation openings through the spectrally-selective solar absorber and through the thermally insulating layer... configured to contact liquid and to allow the liquid to be transported... in order to generate vapor from the liquid
Data Source
AI summary
A localized heating structure includes a spectrally-selective solar absorber, that absorbs incident solar radiation and reflects at wavelengths longer than 2 μm, with an underlying heat-spreading layer having a thermal conductivity equal to or greater than 50 W/(mK), a thermally insulating layer, adjacent to the spectrally-selective solar absorber, having a thermal conductivity of less than 0.1 W/(mK), one or more evaporation openings through the spectrally-selective solar absorber and the thermally insulating layer, and an evaporation wick, disposed in one or more of the evaporation openings in the thermally insulating layer, that contacts liquid and allows the liquid to be transported from a location beneath the thermally insulating layer through to the spectrally-selective solar absorber in order to generate vapor from the liquid. The thermally insulating layer is configured to have a density less than the liquid so that the localized heating structure is able to float on the liquid.