The coldness of outer space is a huge thermodynamic resource that can be utilized as an infinite heat sink that helps in cooling terrestrial objects without the need for electrical energy through a phenomenon known as radiative sky cooling. In the last decade, radiative cooling has seen an increasing attention as a sustainable and clean cooling method and many researchers made smart use of it as a thermal management method. One example in the literature is the radiative cooling of solar cells.
Like solar cells, Light Emitting Diodes (LEDs) are semiconductor devices that deteriorate because of high temperatures. Specifically, the high temperature in LEDs lowers their efficiency and lifetime. Therefore, reducing the temperature by increasing heat dissipation can help in optimizing the efficiency of the LED. In this work, I investigate a novel low-cost solution that can help in reducing the temperature of outdoor LEDs through radiative cooling. The suggested solution utilizes the coldness of outer space to radiatively cool the LED by using a layer of a visible-reflective-infrared-transparent material, nanoporous polyethylene (nanoPE), as a cover to reflect the visible light back to earth while transmitting infrared radiation to outer space. I theoretically discuss the potential cooling performance of LEDs in the suggested design and estimate a cooling power enhancement by 128 W/m2 in ideal conditions compared to current designs. In addition, I study the fabrication and characteristics of nanoPE and show how it can be used as a reflective/diffusive cover for LEDs. Lastly, I experimentally demonstrate the use of nanoPE as a cover for LEDs and show an LED temperature reduction of 15 ⁰C in the laboratory environment and 4 ⁰C outdoor and calculate a relative LED efficiency increase of 28% in the indoor scenario and 4% in the outdoor scenario. This efficiency increase can result in an energy saving of 2.2 TWh in the United States corresponding to at least 0.44 MMT CO2 emission reduction making this cooling solution attractive due to its low cost and high impact.
| Identifer | oai:union.ndltd.org:kaust.edu.sa/oai:repository.kaust.edu.sa:10754/692638 |
| Date | 06 1900 |
| Creators | Almahfoudh, Hasan |
| Contributors | Gan, Qiaoqiang, Physical Science and Engineering (PSE) Division, Ooi, Boon S., Bakr, Osman |
| Source Sets | King Abdullah University of Science and Technology |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Rights | 2024-06-15, At the time of archiving, the student author of this thesis opted to temporarily restrict access to it. The full text of this thesis will become available to the public after the expiration of the embargo on 2024-06-15. |
| Relation | N/A |
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