great roof top vents.http://www.wind-works.org/articles/sm_uswindturbine.html

US Wind Turbine/Bos's Warning
by Paul Gipe

October, 2002 in a posting to awea-wind-home news group. Mike is Michael Klemen, Bos is Ken Bosley.

Mike,

Am I missing something? I haven't followed this closely and I may have missed something on USWT's web site but it sure looks bogus to me and the Bos is on target.

Kudos to you Mike for offering to test this thing. I hope they offer to pay you well for your time. After all, you're a skilled professional and should be compensated. These folks are hoping to make money off this thing by the nature of the aggressive marketing on their web site ("Become a reseller now.")

Ok, here's my take. Correct me if I missed something.

Take #1.

6 x 16-foot squirrel cage VAWT, 20 kW; 6,700 kWh/mo or 80,000 kWh/yr @ 14 mph for $40,0000

This is equivalent to about 9 m2 swept area or about the size of a BWC 1.5 kW or an AWP 0.9 kW.

I guesstimate that the BWC 1.5 kW would generate about 5,000 kWh/yr at a 7 m/s (15.7 mph) site based on Bergey's numbers.

Let's say that the BWC 1.5 kW was about $5,000.

US Wind Turbine 20 kW is then 8 times more expensive than an equivalent Bergey 1.5 kW and they say will produce 16 times more electricity. Note that the Bergey 1.5 kW is a real wind turbine.

Take #2.

Because they say "vane width", let's assume they mean radius, thus the diameter is 12 feet, instead of 6.

12 x 16-foot squirrel cage VAWT, 20 kW; 6,700 kWh/mo or 80,000 kWh/yr @ 14 mph for $40,0000

This is equivalent to about 18 m2 swept area or about the size of a Proven 6 kW.

Based on Proven's overly optimistic estimates of 800 kWh/m2/yr for a 7 m/s site the US Wind Turbine should produce no more than 14,000 kWh/yr.

The USWT claims to produce 4.6 times the optimistic projections of Proven, and will cost 2-3 times more. However, the Proven 6000 is a real wind turbine.

Conclusion

Anytime you see the phrase "thinking outside the box" you should run for the door. Jeffrey Skilling and Ken Lay thought outside the box too.

Unless I've missed something very fundamental, US Wind Turbine's claims are bogus and the prices charged are a ripoff.

Do we have to run through the numbers every time someone foists a squirrel-cage design on a gullible public?

These will make great roof top vents.



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