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Revision as of 20:49, 2 March 2011

Template:305inprogress


Background

The windbelt, first designed by Shawn Frayne, is a device that converts wind into usable electricity by the principle of aeroelastic flutter. Unlike conventional wind turbines, windbelts are effective at producing electricity at low wind speeds. Regions that typically have lower average wind speeds are perfect for windbelt installations. However, windbelt design is relatively new and experimental. New materials and new designs must necessarily be tested to advance this potential source of clean energy.

Oppurtunity Definition

Though conventional windmills produce relatively little power at low wind speeds, windbelts can take advantage of the areas low average wind speeds. So far, three separate groups of Humboldt State University students have built windbelts, each time improving the windbelts design. This project, completed by Greg Pfotenhauer and Agustin Gonzalez serves to further improve upon the design of the windbelt and test new materials.

Literature Review

The following is a review of the literature of the available information relating to windbelts.

Windbelt Basics

Paragraph on the basics. The windbelt, invented by Shawn Frayne in 2004, is a device that converts wind power into electricity. The device is fairly simple, cosisting of a taut string or ribbon strung between two points. Wind blowing across the taut material produces the aeroelastic flutter effect, causing the ribbon to vibrate. This motion is translated into electricity by permanent magnets on the ribbon. The magnets move in and out of electromagnetic coils in accordance with the motion of the ribbon. This induces a current in the coil's wire. [1] A diagram of a typical windbelt is shown below.

WINDBELT.JPG

Unlike conventional wind turbines, which require expensive bearings and gears to be efficient, windbelts are relatively easy to construct at a low cost. This makes the windbelt much more feasible than conventional wind turbines for areas with low average wind speeds. [2]

The following makeup the basic components of a windbelt:

Frame Windbelts are exposed to the elements and are subject to UV radiation, temperature change, moisture, and variable wind speeds. Therefore, the frame must be durable. This means the frame should be as strong as possible.

Consideration should also be taken as to how the windbelt will stand or be mounted. High winds can create a lot of torque upon the windbelt's mount and can damage the windbelt or the structure it is attached to if the mount breaks.

Ribbon The ribbon must be lightweight and thin so it acts like an airfoil when wind blows across it. It must be fairly rigid, as too much elasticity will disrupt the vibration of the ribbon. The ribbon will be taut and subjected to potentially high wind speeds, so the material must have a high tensile strength. Finally, it must maintain its shape over time to be effective (objects that do not deform quickly over time are said to have low "creep.") This being said, there are relatively few materials (so far) that pose as promising materials for windbelt construction. The material used in Shawn Frayne's design is a mylar-coated taffeta. [3] Similar materials, such as kevlar, tape, or camera film can be used alternatively. Further testing of ribbon materials is necessary to improve the efficiency of windbelts.

Magnets Permanent magnets are used to induce current in the coils when vibrating in and out of the coil. The magnets must be fairly lightweight so as not to disrupt the aeroelastic flutter of the ribbon. Neodymium magnets are the most commonly used. [4]


Coils The coils must be made of a conductive metal. Copper is by far the least expensive of metals that conduct well. Coils can also be wound by hand, lessening the cost. [5]

Connectivity Electricity produced by windbelts is of inconsistent voltage. Voltage is relative to windspeed, and so voltage must be regulated for use. Small windbelt systems are capable of supplying power to standard USB ports, while larger systems can supply power for 12V DC circuits. Even larger arrays have the potential for grid-tied AC systems, but these are still in the experimental phase


Quantity Material Source Cost ($) Total ($)
10 board-feet 2x6 ACRC 0.00 0.00
24" Mylar-coated tafetta Donation 0.00 0.00
1 (pk 16) Neodymium magnets Thinkgeek.com 30.00 30.00
4 Copper coils Industrial Electric 25.00 100.00
4' 18 gage wire ACRC 0.00 0.00
4 Bobbins ACRC 0.00 0.00
Total Cost $130.00


Quantity Material Source Cost ($) Total ($)
10 board-feet 2x6 ACRC 0.00 0.00
24" Mylar-coated tafetta Donation 0.00 0.00
1 (pk 16) Neodymium magnets Thinkgeek.com 30.00 30.00
4 Copper coils Industrial Electric 25.00 100.00
4' 18 gage wire ACRC 0.00 0.00
4 Bobbins ACRC 0.00 0.00
Total Cost $130.00

Criteria

The final design for the windbelt was determined by ranking each design by the following criteria. The criteria are ranked from 1-10, with 10 being a criterion of the most importance.

Criteria Constraints Weight
Safety The windbelt must not inflict physical or electrical injury 10
Durability The windbelt must be able to withstand the elements without damage to components 9
Power Capacity Windbelt should produce as much power as possible 9
Environmental Impact Windbelt must use recycled or sustainably obtained materials where appropriate 7
Ease of Alteration Windbelt should be easy to deconstruct to make small changes to the design 4
Cost Project must stay within budget 4
Aesthetics Windbelt must be pleasing to look at 2
Originality Project should include a unique design aspect 2


References

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