Compound Parabolic Concentrators (CPC) are interesting solar collection technology used for reflective, non-imaging optics.[1] They use specifically configured parabolic properties to harness the advantages of the maximum concentration of light energy, making them ideal for harnessing solar power more efficiently.

Learn more about compound parabolic concentrators and their value for maximizing the benefits of solar energy and heat.

History of Compound Parabolic Concentrators

A compound parabolic concentrator is a non-imaging concentrator that uses edge optics. This technology was first discovered in the 1950s and spurred research into non-imaging concentrators.

Then, in 1974, the U.S. Argonne National Laboratory established research on non-imaging concentrators, naming them compound parabolic concentrators.[2]

The initial design of the compound parabolic concentrator uses a flat absorber and, later, a circular tube groove. Over the years, several additions have refined the design. These additions include non-imaging condensers, a secondary compound parabolic reflection, a gap between the concentrator and receiver, and internal cusp reflectors with a heat pipe.

Through continued research and development, the compound parabolic concentrator has seen the potential for virtually limitless low-temperature industrial and residential applications, particularly in industrial solar heat utilization.

Utility of Compound Parabolic Concentrators

An ongoing problem in optical system design is concentrating or funneling light from a large area to a small area. When maximum concentration is desirable, a compound parabolic concentrator is the most effective design option.

A compound parabolic concentrator is an optical device that employs specifically configured parabolic properties to take advantage of the maximum concentration of light energy. The design of these includes a rotated parabolic shape. This shape allows the wide end to collect divergent light and reflect it into the compound parabolic concentrator. The light then concentrates into the narrow output end.

Compound Parabolic Concentrator Manufacturing Process

A compound parabolic concentrator comes in two varieties: solid and hollow. Though they’re manufactured differently, they function the same way and use the same principles.

Solid compound parabolic concentrators are typically made of glass and require high-precision grinding and polishing for high reflectivity.

Hollow compound parabolic concentrators may be manufactured in a number of ways. But they’re typically made using electroforming (an additive manufacturing process). Electroforming is an electrolytic process that deposits a thin metal layer, usually of nickel or copper, into a high-precision polished mold to create metal substrates.

The metal substrate is then removed and electroplated or vacuum coated with a highly reflective metal, such as gold, to maximum reflectivity.

If a compound parabolic concentrator needs a vacuum coating to optimize for a particular wavelength range or performance, the device needs to be tailored to accommodate a two-piece design. This allows each half of the compound parabolic concentrator to be coated with specialized materials, then joined together.

Compound Parabolic Concentrator Use Cases

Solar energy is a renewable and non-polluting source of energy. Solar panels are the most widely used devices to harness solar energy, but solar tracking is necessary to maximize efficiency because of the sun’s changing position around the earth.

The increase in the electricity output can be up to 30% due to solar tracking. Therefore, the use of solar tracking devices makes a world of difference at a solar plant.

Solar trackers have disadvantages, however. They’re designed for climates with minimal snowfall, and they can’t handle extreme weather conditions. They also have an array of components that need to be monitored and serviced, and they consume a lot of electricity.

A compound parabolic concentrator can address the problems with solar trackers. As solar collectors, compound parabolic concentrators can eliminate the need for constant tracking.[3] Instead, they only need seasonal angle adjustments because they concentrate a large amount of sunlight in a small area with minimal loss.

In addition, compound parabolic concentrators don’t consume electricity, they need little maintenance, and they are suitable for virtually all weather conditions – even snow and rain. They’re also reliable and have a long lifespan, making them a strong investment.

The use of compound parabolic concentrators in solar has peripheral applications that require solar stream or solar hot air, such as distillation, evaporation, drying, cooling, refrigeration, and endothermic reaction in the chemical industry.

Solar thermal options are preferred for applications in the metal industry for drying and moisture evaporation. The textile industry uses a lot of hot water. We can obtain the heat necessary for those processes by solar energy gained from solar collectors like compound parabolic concentrators.

Compound Parabolic Concentrators from Apollo Optical Systems

With the rising cost of energy, everyone is becoming more interested in green, clean, and inexpensive solar energy solutions. Apollo Optical Systems is one of the top manufacturers of high-quality compound parabolic concentrators for large- and small-scale projects at economical prices. Contact us today to discuss your custom optics project!

 

Sources:

[1] https://www.sciencedirect.com/topics/engineering/compound-parabolic-collector

[2] https://www.mdpi.com/1996-1073/13/3/695/htm

[3] https://inpressco.com/wp-content/uploads/2017/05/Paper50646-647.pdf

About Dale Buralli

Dr. Dale Buralli has served as the Chief Scientist for Apollo Optical Systems since 2003. In this role, Dr. Buralli is responsible for the design and optical modeling of various optical systems. These systems include virtual or augmented reality, ophthalmic and other imaging or illumination systems. Additionally, he provides support for optical tooling of lens molds and prototypes, including the development of custom software for both production and metrology. Dr. Buralli got his Ph.D. in optics from the University of Rochester in 1991. Now he is an Adjunct Professor of Optics at the University of Rochester’s Institute of Optics.

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