Solar receiver for high temperature applications
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Solution Overview
Problem
Existing high-temperature solar receivers face challenges with semitransparent windows that are critical points of failure due to radiation attenuation, durability issues, and contamination, hindering scalability and efficiency, especially at temperatures exceeding 1000°C.
Innovation Solution
A solar receiver design with a cooling device that supplies a liquid fluid to form a layer on the window, cooling it through convection, conduction, and radiation, maintaining the window at lower temperatures and reducing thermal stress, while allowing solar radiation to be absorbed effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If semitransparent windows are used for radiation access in high-T solar receivers, then radiation transmission is enabled, but the windows become critical points of failure due to durability issues, contamination, and thermal stress at temperatures exceeding 1000°C
Solution Approach 1:
The system separates the window function into two independent parts: a semitransparent window for radiation transmission and a cooling device for thermal management. This segmentation allows the window to focus on its optical function while the cooling device handles thermal stress, eliminating the conflict between radiation transmission and thermal durability.
Solution Approach 2:
The cooling device acts as an intermediary between the high-temperature cavity and the semitransparent window. It supplies cooling fluid that forms a liquid layer on the window surface, absorbing excess heat and protecting the window from direct exposure to high temperatures and thermal stress.
2Use of energy by moving object
If windows are exposed to high-flux irradiation to enable solar energy absorption, then energy input is maximized, but contamination by condensables or dust deposits increases, causing local absorptance increases and hot spots
Solution Approach 1:
The cooling fluid is supplied in advance to form a protective liquid layer on the window surface before contamination can occur. This preliminary protective action prevents dust and condensables from adhering to the window, maintaining its optical properties and preventing hot spot formation.
Solution Approach 2:
The cooling fluid, which could be considered a parasitic element blocking radiation, actually benefits the system by preventing contamination. The liquid layer acts as a sacrificial barrier that protects the window's optical surface, ensuring sustained high energy absorption without degradation from dust or condensable deposits.
3Illumination intensity
If quartz windows with upper limiting temperature of 800°C are used, then radiation transmission is achieved, but active cooling is required which complicates the receiver design
Solution Approach 1:
The cooling system is designed to be self-regulating, where the cooling fluid automatically forms a liquid layer on the window surface based on temperature conditions. This self-service mechanism eliminates the need for complex active cooling control systems, sensors, and actuators, simplifying the overall receiver design while maintaining effective thermal management.
4Stress or pressure
If windows are used for pressurized working fluids, then high-pressure operation is enabled, but the windows must withstand both pressure and thermal cycling, increasing failure risk
Solution Approach 1:
The system separates the pressure containment function from the radiation transmission function. The enclosure withstands the working pressure of the heat transfer fluid, while the semitransparent window only needs to seal the opening and transmit radiation. The cooling device further protects the window from thermal stress, allowing the window to operate in a less demanding mechanical and thermal environment.
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 design enhances thermal efficiency, reduces reradiation losses, and simplifies the receiver's structure, enabling operation at higher pressures and temperatures with reduced energy consumption, making it suitable for industrial processes requiring high-temperature heat.
Implementation Method 1
cooling it through convection, conduction, and radiation
Implementation Method 2
cooling it through convection, conduction, and radiation
Implementation Method 3
cooling it through convection, conduction, and radiation
Implementation Method 4
reduces reradiation losses
Data Source
AI summary
A solar receiver having an enclosure delimiting a cavity that is configured to receive a heat transfer fluid, at least one opening in the enclosure for access of solar radiation into the cavity, at least one window that seals the opening, and at least one cooling device that is configured to cool the window. The cooling device is configured to supply at least one window-cooling liquid fluid to the window, such that the window-cooling liquid fluid forms at least one liquid layer on and/or in the window.