Practical Solar heliostats, with & without mirrors installed
Practical Solar heliostats (model number HE500) include the heliostat housing and an aluminum mirror frame, which fastens to the axles extending out from the heliostat housing. HE500 Price = $995
The Heliostat Housing
This is the heart of the heliostat system. Within the housing are the mechanical and electronic components that control the motion of the heliostat's horizontal and vertical axes, allowing it to reflect sunlight to the target with high precision. Rotation is digitally controlled to an accuracy of 0.11 degrees, equivalent to 5" in 100 ft. Clamps are provided with the heliostat housing so that it can be quickly and easily mounted onto a 2 3/8" diameter pole (see Miscellaneous Materials). Such a pole can be installed into the ground with concrete footing or affixed to a stable structure.
The Mirror Frame
The mirror frame is easily assembled using common hand tools. Four struts form a pyramid shape behind the mirror frame, which provides structural support in high winds. The mirror frame is designed to carry eight standard 12" x 12" (30.48 cm x 30.48 cm) glass mirrors, also called mirror tiles. Mirrors are not included (see Miscellaneous Materials). In many cases the mirrors can be installed flat, but the user has the option of focusing the mirrors by tilting them slightly during installation. The User’s Manual includes detailed instructions for this mirror focusing technique. Using this technique for a target 200 feet away from the heliostat, one can achieve a round sun spot 36” in diameter. For a target 50 feet from the heliostat, one can achieve a round sun spot 18” in diameter – a 4x sun concentration (10 heliostats at this distance would yield a 40x concentration, etc).
Heliostat Features and Advantages
- Each heliostat is individually programmed and controlled with the system software. A heliostat can have multiple targets, so it can perform different functions at different times of day or year.
- Heliostats can switch between targets at the user’s command, or switch automatically when using the timer in the control software. Programming a new target for any heliostat takes only a few minutes.
- Unlike other heliostat systems that must be installed in a particular pattern because they are mechanically linked, Practical Solar heliostats require no installation pattern.
- Design is extremely rugged & maintenance-free. External parts are stainless steel, aluminum and glass – all rust free and extremely durable against the elements.
- The mirrors require little or no maintenance in most locations. Rain diminishes the accumulation of dust and debris, so mirror reflectivity is not significantly diminished over time.
- Each heliostat delivers about 3000X more energy than it consumes. A nightlight running all night consumes more power than 100 heliostats running all day.
- Installation is accomplished with household tools. Handy homeowners can perform the installation themselves, avoiding installation costs.
- Heliostats are stable in high winds with the pyramid-shaped structural support of 4 struts.
- Mirror frame (including struts) is shipped in a compact tube and assembles in minutes.
Heliostat Specifications
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Reflector area |
8 ft2 (0.74 m2) |
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Weight |
20 lbs (9 kg) includes mirror frame and heliostat housing; excludes reflectors |
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Electrical interface |
2-conductor cable, stranded & unshielded with overall jacket (see cable gauge guide in Miscellaneous Materials) |
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Electrical power consumption |
< 100 milliwatts (0.1 watts) average; < 1 watt-hour/day |
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Positioning accuracy |
0.11 degrees |
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Rotational limit |
+/- 60 degrees Azimuth; +50 / -5 degrees Altitude |
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Operating temperature range |
-20°C to +50°C (-4°F to 122°F) |
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Operating humidity range |
0-100% relative humidity |
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Maximum wind speed (operation) |
80 kilometers / hour (≈ 50 MPH) |
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Maximum wind speed (structural) |
150 kilometers / hour (≈ 90 MPH) |