Solar concentrator

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A solar concentrator concentrates the power of the sun onto a small area. This energy is harnessed in a variety of ways. For example, a system called SCARLET is currently flying on Deep Space I.

Designs

Lenses

A variety of lense designs are used to concentrate sunlight. A lense may be a simple piece of curved glass or plastic, or a complex Fresnel lense.

Mirrors

Fields of mirrors are used in some concentrated solar facilities on Earth. The individual mirrors rotate to track the sun. The construction can be made light weight from polymers, e.g. Mylar and Hostephan. Computer simulations of radiation damage have shown that an aluminum covering of at least 0.1 mm thickness is necessary.

Fiber Optics

Utilization of Focused Solar Radiation

Photovoltaics

Solar concentrators are often used in conjunction with solar panels to increase the panel's output. This maximizes the efficiency of a limited number of solar panels.

Thermal Engines

The energy of the sun can boil liquids, causing changes in pressure. These pressure changes are harnessed by thermal engines. It is likely that liquids other than water will be used, due to the low temperatures on the surface. Carbon dioxide and carbon monoxide are both available as working fluids. Common thermal engine designs include the Sterling engine and the steam engine. Since the angular size of the sun as seen on Mars is smaller than it is on Earth, a larger mirror is needed to get the same sized image of the sun at about the same temperature as on Earth. Solar thermal engines should be capable of powering electric generators on Mars.

Thermoelectric Generators

Thermoelectric materials convert heat into electricity.

Photosynthesis

Greenhouses are a good target for solar concentration. The natural sunlight on Mars is less than half that on Earth.

Lighting

Concentrated sunlight can be used to light settlements during the day.

Dangers

Concentrated solar radiation can become hazardous in some situations.

Radiation Damage

If solar radiation is concentrated for use in greenhouses or settlements, the harmful parts of the electromagnetic spectrum need to be filtered.

Vision Damage

Looking directly into concentrated sunlight can damage vision.

Heat Damage

Objects passing through the focus of a solar concentrator can be exposed to intense light and extremely high temperatures.

Maintenance effort

The cosmic and solar radiation causes damage upon the concentrator mirrors. The particle bombardment causes blistering and foil carbonization. A lifetime of 10 years is assumed, thereafter the mirrors have to be replaced.

Solar concentrators are susceptible to losses due to atmospheric diffraction and dust. During a dust storm concentrators lose much of their efficiency.

External links