Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Letting in the Light

31.01.2014
Self-cleaning solar panel coating optimizes energy collection, reduces costs

Soiling -- the accumulation of dust and sand -- on solar power reflectors and photovoltaic cells is one of the main efficiency drags for solar power plants, capable of reducing reflectivity up to 50 percent in 14 days.


iStockphoto image

Solar power reflectors collect dust and sand, reducing their energy efficiency—a challenge ORNL researchers are tackling by developing a low-cost, anti-soiling coating.

Though plants can perform manual cleaning and brushing with deionized water and detergent, this labor-intensive routine significantly raises operating and maintenance costs (O&M), which is reflected in the cost of solar energy for consumers.

Under the sponsorship of the Department of Energy’s Energy Efficiency and Renewable Energy SunShot Concentrating Solar Power Program, Oak Ridge National Laboratory is developing a low-cost, transparent, anti-soiling (or self-cleaning) coating for solar reflectors to optimize energy efficiency while lowering O&M costs and avoiding negative environmental impacts.

The coating—which is being designed by members of the Energy and Transportation Science Division, including Scott Hunter, Bart Smith, George Polyzos, and Daniel Schaeffer—is based on a superhydrophobic coating technology developed at ORNL that has been shown to effectively repel water, viscous liquids, and most solid particles. Unlike other superhydrophobic approaches that employ high-cost vacuum deposition and chemical etching to nano-engineer desired surfaces, ORNL’s coatings are deposited by conventional painting and spraying methods using a mixture of organics and particles. In addition to being low-cost, these methods can be deployed easily in the field during repairs and retro-fitting.

There are, however, challenges to the successful development of such a transparent, anti-soiling coating. First, the coating must be very superhydrophobic to minimize the need for occasional cleaning, and it must have minimal (or even zero) effect on the transmission and scattering of solar radiation between the wavelengths of 250 to 3,000 nm. To meet these requirements, the coating must be no more than a few hundred nanometers thick, and the embedded particles must be considerably smaller. The extremely thin coating must also be durable under environmental exposure, including UV radiation and sand erosion, and be compliant according to the US Environmental Protection Agency Clean Air Act emission standards—which limits the selection and combination of particles and organics that can be used effectively.

During the first year of this project, researchers experimented with a variety of Clean Air Act–compliant organics and silica particles of different sizes. They arrived at a particular formulation combining organic compounds with silica particles, which are dispersed in two sizes to enhance area coverage of particles within the coating.

The anti-soiling coating exhibited excellent superhydrophobic properties, losing less than 0.3% of transparency over the entire solar radiation wavelength range. When exposed to several hundred hours of accelerated UV radiation and one hundred hours of salt fog exposure, the coating exhibited no degradation in superhydrophobic or optical transmission properties. Also, when glass slides with the anti-soiling coating were exposed to sand and dust in a custom-made wind tunnel, the particles did not adhere to the coated surface of the slides—showing great potential for its use in harsh environmental conditions.

In addition to anti-soiling coating for solar applications, ORNL researchers are using their superhydrophobicity expertise to develop anti-soiling cool roof coatings, as well as anti-icing and anti-condensation coatings for air conditioning and evaporative cooling applications, respectively. Going into 2014, the project has been funded for another year and will optimize the coating and perform accelerated exposure tests, as well as begin development on a scalable coating technique and perform small-scale field testing.—Katie Elyce Jones

Bill Cabage | Newswise
Further information:
http://www.ornl.gov

More articles from Power and Electrical Engineering:

nachricht A big nano boost for solar cells
18.01.2017 | Kyoto University and Osaka Gas effort doubles current efficiencies

nachricht Multiregional brain on a chip
16.01.2017 | Harvard John A. Paulson School of Engineering and Applied Sciences

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Helmholtz International Fellow Award for Sarah Amalia Teichmann

20.01.2017 | Awards Funding

An innovative high-performance material: biofibers made from green lacewing silk

20.01.2017 | Materials Sciences

Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery

20.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>