Helio™ Solar Tracker

 

Helio™ Solar Tracker

U.S. Patent  7,799,987

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       The Helio™ is a solar tracker invented by Steve Hines as a mounting platform for solar cells and other solar collectors to improve their efficiency.  A farm of modular Helio solar trackers can be wired together to supply the needs of a house or village.

       The Helio is a hollow tube covered with a water absorbent material and which is supplied with water at its base.  Capillary action draws water up the surface of the tube, filling the pores and expanding the covering.  During the night, the entire surface of the tube becomes saturated causing the tube to expand slightly.  In the morning, moisture on the sunny side evaporates, causing that side to shrink.  The combination of the expanded wet side and shrunken dry side mimicks the action of the heliotrope and other flowers that follow the sun.  When a photo voltaic cell or other solar collector is mounted to the top surface of the Helio, its efficiency is optimized during the tracking period.

 

Background:

      This swelling and shrinking effect can be seen with a damp kitchen sponge.  When the damp sponge is left flat on the counter top at night, it dries out.  The top surface which has more exposure to the air dries first, evaporating the water in the cellulose fiber which shrinks the top of the sponge (or more accurately, allowing it to slightly collapse when the water molecules vacate the spaces in the sponge), and making the sponge curl upward.

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       In the animation above, which represents approximately 6 hours of time, a cluster of modular floating Helio solar trackers, loosely lashed together, reacts to the changing position of the sun.  Internal compression springs can be seen through the fabric. Solar cells mounted to the top surface operate at peak efficiency during the tracking period.

      The Helio™ solar tracker can be constructed using a variety of materials; however, in general there is a tubular surface made of a material that expands when wet and shrinks when dry, and an internal support to keep the tube extended.  The covering is typically cotton or cellulose sponge, colored black to help absorb sunlight.  The support can be an internal compression spring (fiberglass, titanium, stainless steel, etc.), or a tube of foamed plastic stiff enough to support its own weight, or an air-inflated tube.

      Every combination of construction materials will have its own strength and physical properties (wet-to-dry shrink ratio, absorbency, stiffness, etc.) which will determine the appropriate length-to-diameter to bend to the desired tracking angle and support its own weight.


 

Solar Collector Options:

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Empty mounting surface with four  mounting holes and a central electrical-wire access hole.
 
Solar cell attached to top mounting surface, works at peak efficiency during the tracking period.
 
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Smaller solar cell with Fresnel lens to concentrate sunlight and improve efficiency.  Fiber-optic bundle can replace solar cell to pipe light into a building.

Sterling-cycle engine with parabolic reflector concentrator, and electrical generator.  This approach would not be viable without solar tracking.  

 
 

Construction Alternatives

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      A simple technique for supporting the top mounting surface, where there is depth below the base on a lake or pond, a long pole can be inserted through a loose hole in the base.  The pole has a float mounted under the floating Helio base.  A counter weight at the bottom of the pole keeps the top of the solar tracker up.

     Where a deep water supply is unavailable, for example on city building roof tops, the tube can be supported with modular sections.  Each section can tip at a slight angle relative to the one below it.. The total angular freedom  of the top covers the required tracking angle of the sun, typically ±45° to cover 6 hours of time.  Shown on top is a small solar cell and air-spaced Fresnel lens.  The bottom link is bolted to the bottom of the water pan.  An electrical wire is routed from the solar cell through wire-access holes in each section (not shown) and out the bottom.


 

Efficiency Comparisons:

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A, Solar cell with no tracking or concentrator (inefficient but included for comparison with B).
 
B, Tracked solar cell but with no concentrator.  Shown is a Helio tube with solar cell on its top surface.  The tubular Helio keeps the solar cell perpendicular to the sun during the tracking period, shown as 9 AM – 3 PM.
 
C, Solar collector with no tracking but with a concentrator (extremely inefficient but included for comparison with D).  Shown is a parabolic reflector and solar collector facing straight up.
 
D, Solar-tracked collector with concentrator.  Shown is a tube with a parabolic reflector concentrator and solar collector.  This arrangement with a concentrator, whether parabolic reflector or Fresnel lens, mounted to the Helio™ provides the most benefit.
 
SolarTracker10ForestTower
 

      The Helio is ideal for remote locations such as forest ranger towers which must have electrical power for radio communication and signal lights.  Helios are submerged in a roof-top cistern and trough which supplies the solar trackers with water.

      The Helio™ is based on simple technology and which requires little or no maintenance, making it ideal for third-world countries.  A Helio farm can be set up across any wet surface, such as a pond or lake, reflecting pool, rice paddy or roof of an office building.  If the water supply dries up, the Helios lack any directional bias and therefore stand in their vertical default position.  When it rains, the Helios resume operation to increase electrical energy output.  


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Hines' original entry, p. 100 in lab notebook #1:


 

      This is a technology announcement and license offer.  This is not a product being offered for sale.  HinesLab seeks a licensee for the Helio™ technology.  Interested manufacturers, please contact Steve Hines at:

HinesLab, Inc.

Glendale, California, USA
ph. 818-507-5812