Detailed Product Description

The solar heliostat uses mirrors to reflect sunlight onto a fixed target.  One heliostat reflects up to 600 watts of heat. 

SolarTracker heliostats calculate the position of the sun and move its mirror frame (up, down, left, right) to reflect the sunlight onto a fixed target chosen by the user. Each heliostat reflects about as much visible light as forty 100-watt light bulbs, as well as 600 watts of thermal energy (heat). Heliostat are individually programmed and controlled by the software, which runs as a background program on the users computer. This means that an array of multiple heliostats can direct sunlight to different targets simultaneously, or to a common target for concentrating solar power (CSP). Users can save multiple targets for a single heliostat and switch between the targets at will, or use the softwares timer function to switch between targets automatically.

The user also has the option of individually focusing the 8 mirrors in a heliostats mirror frame to customize the size and shape of the reflected sun spot. Unconcentrated sunlight is suitable for many natural lighting and space heating applications, but users have the option of achieving a 4X concentration per heliostat. Heliostat arrays can achieve concentrations of up to 250 suns.

Applications:

Natural Lighting

Thermal

Direct thermal applications include:

• Interior space heating
• Swimming pool heating
• Drying paint or wood, melting ice dams on roofs, and other miscellaneous direct thermal applications  

Thermal applications with ancillary products include:

• Building heating and cooling (HVAC)
• Potable hot water heating
• Air conditioning (with hot water-driven absorption chillers)
• Thermal desalinization
• Hydrogen (H2) production (for fuel cells)
• Low temperature industrial and agricultural applications (e.g. drying of wood, grain, leather)
• Powering a thermal engine (see Electrical Power below)

Electrical Power

Heliostats with thermal engines

Thermal engines convert heat to mechanical power. A generator can then convert that mechanical power to electrical power at near 100% efficiency. Most thermal engines require extremely high temperature input (e.g. 600°C [1112°F] and higher). Organic Rankine Cycle (ORC) microturbines and some Stirling engines can operate with inputted temperatures below 232°C (450°F) and are more compatible for use with heliostats.

Heliostats with concentrator cell technology (advanced PV)

Most intriguing is the use of concentrator cell technology or advanced photovoltaics to directly convert concentrated solar energy to electricity. Such technology might be combined with heliostats to create a distributed generation system capable of delivering 5-50 kW of electrical power.

Creative Lighting Applications

• Growing vegetables in winter or in shaded areas
• Lighting windowless rooms (like medical and dental exam rooms) by using heliostats in conjunction with tube & mirror natural lighting systems
• Illuminating museum and art exhibits
• Sign illumination
• "Moonlighting" a patio or deck at night (software can be adapted for moon tracking)
• Casting sunlight through a large prism  

Creative Thermal Applications

• Drying shaded exterior walls to reduce mildew
• Melting ice dams on roofs
• Drying paint or glue outdoors
• Drying linens on a clothesline
• Drying firewood

What is a Heliostat and how is it used?

A heliostat is a mirror that tracks the sun. A heliostat array is a group of heliostats. SolarTracker heliostats track the sun in order to reflect its energy onto a fixed target. An array may direct the sun's energy to a common target, much smaller in size than the summed areas of the reflectors (0.74m² reflector area per heliostat). In this case, the sun's energy is concentrated on the target. Systems that collect and concentrate solar energy are concentrating solar power ("CSP") systems.

An example of a non-concentrating application is natural lighting (a.k.a. daylighting). Heliostats can direct sunlight to areas inside buildings that would not ordinarily receive sunlight, such as through north-facing windows, or down into atriums, usually by bouncing sunlight off of a secondary reflector over the atrium. Heliostats have also been used to illuminate outdoor parks previously shadowed by surrounding buildings.