Radiative Cooling for Concentrating Photovoltaics
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional thermal management techniques for renewable energy systems like photovoltaics (PV), thermophotovoltaics (TPV), and concentrating photovoltaics (CPV) are inefficient, especially at high temperatures, leading to reduced efficiency and shorter lifetimes, as they rely on convective or conductive cooling methods that require extra energy and increase costs.
Innovation Solution
Implementing radiative cooling as a passive and compact cooling mechanism that sends waste heat directly into space, using materials and designs that optimize emissivity and transmittance to achieve significant temperature drops and increased open-circuit voltage in PV systems, particularly through the integration of radiative coolers with heat sinks and optical concentrators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If convective or forced air cooling is used, then heat dissipation is improved, but energy consumption increases and system complexity increases
Solution Approach 1:
The patent replaces mechanical cooling systems (fans, pumps) with a passive radiative cooling system that uses selectively emissive coatings to dissipate heat through thermal radiation in the 8-13 μm atmospheric window, eliminating the need for moving parts and external energy input while maintaining effective heat dissipation
2Temperature
If liquid cooling systems are implemented, then cooling efficiency is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the cooling function from complex liquid cooling systems and implements it through a simple passive radiative cooler with selectively emissive coatings, removing the need for liquid circulation pumps, heat exchangers, and associated control systems while maintaining effective temperature management
Solution Approach 2:
The radiative cooling system is self-regulating, automatically adjusting heat dissipation based on temperature differences and atmospheric conditions without requiring external control systems, pumps, or energy input, thereby simplifying the overall system architecture
3Temperature
If conventional cooling methods are used, then heat management is achieved, but reliability decreases due to additional components
Solution Approach 1:
The passive radiative cooling system operates autonomously without moving parts, pumps, or external power sources, eliminating failure points associated with mechanical components while continuously managing heat through thermodynamically stable radiative heat transfer in the atmospheric transparency window
Solution Approach 2:
The patent replaces unreliable mechanical cooling systems with a passive radiative cooling mechanism that has no moving parts, eliminating wear, friction, and mechanical failure modes while maintaining effective heat dissipation through electromagnetic radiation
4Temperature
If radiative cooling is used at low temperatures, then cooling effect is limited, but at high temperatures radiative cooling becomes highly effective
Solution Approach 1:
The patent employs selectively emissive coatings with peak emissivity in the 8-13 μm atmospheric window that are optimized for the specific operating temperature range of CPV systems, allowing the radiative cooler to achieve maximum effectiveness at the elevated temperatures where CPV systems operate while maintaining adaptability through material selection
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
Radiative cooling can achieve temperature drops of 5 to 36°C and an 8% to 27% relative increase in open-circuit voltage for GaSb solar cells, extending the lifetime of CPV systems while being more efficient and cost-effective than traditional cooling methods, with cooling power growing faster than convection and conduction at high temperatures.
Implementation Method 1
Radiative cooling can reject significantly more waste heat than convection and conduction at high temperatures by sending it directly into space
Implementation Method 2
an optical concentrator (such as a Fresnel lens) positioned between the mirror 20 and the solar cell 15 for focusing sunlight onto the solar cell 15
Implementation Method 3
a mirror 20 positioned below the solar cell 15 and oriented to direct sunlight onto the solar cell 15
Data Source
AI summary
A radiatively cooled solar array, including a downwardly-facing solar cell and a mirror positioned below the solar cell and oriented to direct sunlight onto the solar cell. The assembly also includes a heat sink in thermal communication with the solar cell and disposed opposite the mirror. The heat sink is in radiative communication through Earth's atmosphere with outer space.