I just signed up with cleantechnica.com.
I’m intending to search about a tiny bit and make contact with fascinating folks and discover a couple of points.

I am hoping this did not get put in the wrong category. I pray you’ll forgive me if it does.

——————–

ELWOOD CRANE
Retail Inventory Control Analyst

2) People considering a wind turbine would be wise to do a 1 year wind site assessment to learn their likely wind energy availability in the form of a Rose chart and not rely on a local wind chart.

3) Turbine manufacturers always state the rated power for the highest operating speed rather than a realistic typical 11mph speed to look really good. At the rated speed 29mph, the Falcon 600W models with 1.3m² swept area receives 1714W wind energy so the 600W is 35% eff. That is very high for this H-bar type Darrieus VAWT.

4) Your “How To Calc The cost per kWh” accepts the vendor probability of getting a 29mph wind for 10% of the time but this has no relationship to a customers likely wind speed.

A much better guesstimate is to use your ave wind speed then double the final result or use 26% faster ave wind speed for same result. The Weibull probability curve for wind speeds and the cube conversion to wind power curve is well explained at windpower.org in the guided tour.

So if your 12kW VAWT is sited with a very good ave wind speed of 15mph (6.75m/s) you can use 19mph (8.5m/s) to calc the ave turbine power.

Since we don’t know the 12kW model’s eff we can prorate its rated 12kW power by cube of wind speed ratios. 12kW *(19/29)³ is 3.38kW which would give you ~2,470kWh/mth rather than your. A 12mph ave wind site (using a 15mph fig) producing 1,25kWh/mth is now really departing from your 3,500kWh/mth and trebling the ROI.

All the Falcon spec sheets show a power curve that are either a mostly linear or mostly square curve when they should be more cubic so I don’t trust them.

Darreius VAWTs have huge centrifugal forces at the blades because they can travel many times the wind speed. That obviates a gear box but they need much more substantial structures than drag based VAWTs and the blade life expectancy may not be nearly as good as a HAWT rotor. The towers need to be quite tall to ensure the wind speed at top and bottom of the blades is comparable to maximize eff and reduce blade stress. WePower specs their towers at about the same height as the rotors which seems too short.

Don’t be surprised if these turbines are more expensive than HAWTs.

So I’m a bit dubious about this company re the power curves, and structural specs.

(Please delete if this double posted)

2) People considering a wind turbine would be wise to do a 1 year wind site assessment to learn their likely wind energy availability in the form of a Rose chart and not rely on a local wind chart.

3) Turbine manufacturers always state the rated power for the highest operating speed rather than a realistic typical 11mph speed to look really good. At the rated speed 29mph, the Falcon 600W models with 1.3m² swept area receives 1714W wind energy so the 600W is 35% eff. That is very high for this H-bar type Darrieus VAWT.

4) Your “How To Calc The cost per kWh” accepts the vendor probability of getting a 29mph wind for 10% of the time but this has no relationship to a customers likely wind speed.

A much better guesstimate is to use your ave wind speed then double the final result or use 26% faster ave wind speed for same result. The Weibull probability curve for wind speeds and the cube conversion to wind power curve is well explained at windpower.org in the guided tour.

So if your 12kW VAWT is sited with a very good ave wind speed of 15mph (6.75m/s) you can use 19mph (8.5m/s) to calc the ave turbine power.

Since we don’t know the 12kW model’s eff we can prorate its rated 12kW power by cube of wind speed ratios. 12kW *(19/29)³ is 3.38kW which would give you ~2,470kWh/mth rather than your. A 12mph ave wind site (using a 15mph fig) producing 1,25kWh/mth is now really departing from your 3,500kWh/mth and trebling the ROI.

All the Falcon spec sheets show a power curve that are either a mostly linear or mostly square curve when they should be more cubic so I don’t trust them.

Darreius VAWTs have huge centrifugal forces at the blades because they can travel many times the wind speed. That obviates a gear box but they need much more substantial structures than drag based VAWTs and the blade life expectancy may not be nearly as good as a HAWT rotor. The towers need to be quite tall to ensure the wind speed at top and bottom of the blades is comparable to maximize eff and reduce blade stress. WePower specs their towers at about the same height as the rotors which seems too short.

Don’t be surprised if these turbines are more expensive than HAWTs.

So I’m a bit dubious about this company re the power curves, and structural specs.

(Please delete if this double posted)