Wind turbines with many small generators

[256bits]

So in theory it will produce 1kW minus Beltz law and only 0.59kW would be available. But let's not debate about windspeed

At 10m/s 600 w is the power of the moving wind.
Theoretical Betz limit is 59% of that, or 354 w.

For a real windmill, efficiency might be 80% of that or 283 w. extracted as useful power.

With increased wind speed, efficiency of the machine will drop, but since power within the wind increases as V³, and extracted power can also increase, but only if the generator, usage devices, or storage devices can use it. If not, then the rotor speed has to be scaled back, or the excess energy dumped.

With decreased wind speed, efficiency also drops and so does power within the wind. - a double whamy.

 

[Jax Dax]

Only if the electronics is really, really bad. Even a laptop charger reaches 80% or more with multiple internal conversion steps.There is no 60% efficient wind turbine. And even if there would and if the generator would be 100% efficient (it is not), 40% loss would leave at most 36% total efficiency.
Electric heating is basically 100% efficient. There is no energy lost to heat ;). A heat pump can reach an even higher efficiency.
What do you suggest as alternative? A separate wind turbine and a house-wide grid for every possible voltage some device might need?

Short answer is Yes, a 12v and 220v (or something similar) should be standard imo, if we don't stop wasting we will continue overproducing to compensate and we pay for it.
With LEDs there is no reason why lighting should be 220v.
With specially wound generators 12 and 220v is possible (multi taps) generators can supply almost any voltage required.
Understand any power your inverter supplies is 40% less than generated (less but complicated 220>12 = 20% loss, 12> 220v = 20% loss = 37% loss in total and rounded to 40%)

Only if the electronics is really, really bad. Even a laptop charger reaches 80% or more with multiple internal conversion steps.There is no 60% efficient wind turbine. And even if there would and if the generator would be 100% efficient (it is not), 40% loss would leave at most 36% total efficiency.
Electric heating is basically 100% efficient. There is no energy lost to heat ;). A heat pump can reach an even higher efficiency.
What do you suggest as alternative? A separate wind turbine and a house-wide grid for every possible voltage some device might need?

When transforming electricity up or down there is a loss in efficiency, most PF is between 80 and 90%. So your 5kW unit produces 5kW 220v, goes to a transformer and reduced to 12v, only 4kW is received by the batteries, the loss over the transformer is 1kW, that is stored in the batteries, then the 12v is inverted to 220v again another 20% loss. This is all losses we can prevent.

 

[256bits]

I have always wondered why they don't have a row of propeller followed by a row of Savonius turbines.

Savonius turbines are only about 30% efficient, and if the wind has already had say, 50% of its power extracted ( an efficient propeller ) upwind, that leaves only 15% available that can be extracted with the 2nd row.

 

[Jax Dax]

At 10m/s 600 w is the power of the moving wind.
Theoretical Betz limit is 59% of that, or 354 w.

For a real windmill, efficiency might be 80% of that or 283 w. extracted as useful power.

With increased wind speed, efficiency of the machine will drop, but since power within the wind increases as V³, and extracted power can also increase, but only if the generator, usage devices, or storage devices can use it. If not, then the rotor speed has to be scaled back, or the excess energy dumped.

With decreased wind speed, efficiency also drops and so does power within the wind. - a double whamy.

Agree, wind turbine are extremely complicated with current technology, it all looks so easy until you do it. And the salesmen make it sound to good to be true

 

[mfb]

Short answer is Yes, a 12v and 220v (or something similar) should be standard imo, if we don't stop wasting we will continue overproducing to compensate and we pay for it.
With LEDs there is no reason why lighting should be 220v.

You cannot distribute 12 V over a city-sized power grid, losses in the cables will ruin that. It would be possible to have a central converter instead of many smaller ones, but I don't think that outweighs the additional effort of more cables everywhere.

Understand any power your inverter supplies is 40% less than generated (less but complicated 220>12 = 20% loss, 12> 220v = 20% loss = 37% loss in total and rounded to 40%)

It is not. Also, why should the generator output be transformed like that?

 

[Jax Dax]

Im not good at the quotes thing so I hope you don't mind a straight answer.
q1
agreed, but let's keep national grid and home grid separate otherwise the convo gets very confusing
We are talking about wind generators for home use, so let's stay within the house.
q2
every transformation of electrical current suffer hysterisis and eddy current losses, magnetic and resistance losses, approximate efficiency is 80 to 90% so the resultant loss is 10 to 20%. each time electricity flows through a transformer. (its why Edison lost the lighting contract, lol)
Also, why should the generator output be transformed like that? same reason we don't only make 4" nails.
-for example, if your house had 12v lights.
a multi wound generator operating 12/220v - 12v would provide lighting power at 0 losses (technicaly) it is rectified and feed into the batteries with 0 loss, the lights consume it with 0 loss, net effect is you have saved 0.6kW of power generated.
lets assume 1kW of power is used by the lights, 220v transformed to 12v inverted to 220v the 1kW is needed by the lights, the generator must supply 1.6kW @ 220v to have the 1kW output for the lights.
1.6 x 0.8 = 1.28kW to the batteries and 1.28 x 0.8 = 1.02kW supplied to the lights
from the equation you can see a bigger battery bank is needed to power the lights

 

[mfb]

220v transformed to 12v inverted to 220v

Well, no one would do such a thing.

 

[Jax Dax]

http://www.saferwholesale.com/Aero-...IlrY2ChPC11z70VFogXM20cfwmH6GOOrM3BoCparw_wcB
hats the unit Russ was looking at.
the specs provided
Specifications

• Power: 5KW
• Blade Diameter (ft): 20
• Rated Rotated Speed: 200
• Rated Wind Speed (mph): 22
• Max Voltage: 7KW
• Output Voltage: 220v NOTE! TURBINE GENERATION
• Start Up Wind Speed (mph): 6.7
• Operating Wind Speed (mph): 6-55
• Security Wind Speed (mph): 110
• Height Of Tower (ft): 30
• Weight Of Top Section (lbs.): 630
• Output Controller System: Charger Inverter NOTE! CHANGING GENERATOR 220V TO 12V FOR THE BATTERIES
• Capacity & Quantity Of Battery (reference): 12V 200AH 18pcs NOTE! STORAGE OF THE GENERATOR POWER

the 12 /220v Invertor is not included with their system, its an optional extra.
By the way it is normal, all turbines (well most boats etc use a 12v generator) produce a higher voltage, needs thinner cables than 12v

 

[mfb]

By the way it is normal, all turbines (well most boats etc use a 12v generator) produce a higher voltage, needs thinner cables than 12v

Corollary: Conversion losses are lower than losses in cables.
Also, you could put batteries in series to get 220 V (still needs AC/DC conversion of course) if it would help.

 

[Jax Dax]

The picture I am trying to paint is this,
Our electrical system is a Heath Robinson affair, they are antiquated and out dated for the new wave generation equipment we use. All current systems were designed and developed in the 1900s a long time before semi conductors and electronics. We have bound ourselves to the system and struggle to accept the inevitable. The same as the old die hards in there 1950s Cadillac that needed lead fuel. I am not saying the generation or the distribution systems in place are wrong. It is us the home owners that refuse to budge we are bound by institutions who have not kept up with technology, they keep adapting and adapting instead of rectifying the source.
Changing of electricity after your mains supply to any other voltage costs you money, my estimates are between 1 and 3kW of power is wasted per hour in the average house hold every evening, so let's say 4hrs x 1kW = 4kW (using the minimum) x 365.25 = 1461 kW per household per annum 0.4 euro (was the price mentioned I think) 584 euro wasted just in lighting costs wasted. To change just the lighting has a major impact on your bill.

 

[Jax Dax]

Corollary: Conversion losses are lower than losses in cables.
Also, you could put batteries in series to get 220 V (still needs AC/DC conversion of course) if it would help.

Yes that is possible, haven't looked at 220/220 invertors tbh ( never thought of that )
I'm only designing the turbine and generator atm so haven't looked at storage or invertors as yet.