Newbie seeking advice, small wind turbine.

XT600

Hi all, I recently bought myself a second hand turbine (Airforce 1, 1kw 48v output, 5 blade) I live in town, in the UK, and understand that conditions here are far from ideal given the surrounding buildings/trees etc and that due to planning laws I'm unable to mount the turbine at any useful height. It's currently mounted on a 2" pole roughly 5 meters high. My grid tied PV panels currently heat my water via a diverter, which works great during the summer months but in the winter just aren't enough. I was hoping that the wind turbine would supplement these, pushing a bit of power into the system during the night for example. However, the turbine seems to spend more time spinning around on it's pole rather than rotating the blades. I assume this is down to the turbulent air ? Do you think I'm wasting my time with this, or is there a way to make this work better? Would it be better to fix the unit to the prevailing wind direction and not let it turn? 

706jim

 Do you think I'm wasting my time with this,

Yes

BB.

The short answer is as Jim says. Your environment (city, buildings, "short towers", etc. makes it impossible to have a successful wind turbine installation--Let alone the issue of finding/building a wind turbine.

There is very little harvestable wind energy in turbulent airflow. The tower typically needs to be something like 10-30+ meters tall to get into laminar/clean/non-turbulent airflow. Your turbine "hunting" all the time typically indicates turbulent airflow (although, there are some poor turbine designs that that similar issues).

You could do things like fly a kite. find how high the kite needs to fly to get into non-turbulent air.

How much discussion do you wish to get into... We try to backup our answers with data. Here is a 10+ year older thread about wind power (the vendors have disappeared, but the physics has not changed):

https://forum.solar-electric.com/discussion/3638/small-windpower-a-scam-survey-says-so/p1

The Netherlands did a long term (1 year) test of "residential sized" wind turbines. And the results were "poor" (at least). Many of the detailed reports are in Dutch--But your browser may translate, or you can use Google Translate to read the results.

https://forum.solar-electric.com/discussion/3638/small-windpower-a-scam-survey-says-so/p1

Solar is usually the best answer for most people... There is solar PV/Electric panels and power systems... And also solar thermal (heating water typically). But you have to be in an region/area with a "useful" amount of sun and the panels have to get "shade free" sunlight during most of the day. For example for Plymouth UK:

http://www.solarelectricityhandbook.com/solar-irradiance.html

Plymouth UK
Average Solar Insolation figures

Measured in kWh/m2/day onto a solar panel set at a 25° angle from vertical:
(Optimal winter settings)

Jan	Feb	Mar	Apr	May	Jun
1.38	2.21	3.00	4.10	4.39	4.25
Jul	Aug	Sep	Oct	Nov	Dec
4.21	4.16	3.65	2.49	1.76	1.15

More or less, at least 3 hours of sun is a good start... 

Otherwise, the most cost effective place to start is conservation. It is almost always cheaper to conserve energy than to generate energy.

Lots of insulation, efficient lighting and home appliances, possible use of mini-split heat pumps for heating/cooling, etc..

But any changes to your home has to be done correctly. Things done wrong can have terrible consequences.

https://en.wikipedia.org/wiki/Grenfell_Tower_fire

-Bill

XT600

Thanks Bill for the comprehensive reply.
I have practically rebuilt my old (1760) terraced house over the last 10 years and it's probably the best insulated house in the county! It takes very little to heat, and retains the heat well. I have two woodburners, and plenty of free wood from my job in the building trade. I have around 4kw of PV panels, which provide most of my needs from March to October with any excess diverted to the water heater. I could add some more panels which would help a little, but are of no use when there are several consecutive dark days.
The reason for the wind turbine is to try and create a little more power during the long dark hours of the winter. We are coastal and get more than our fair share of windy days. I don't expect miracles, but anything is better than nothing, particularly as it has cost me very little to obtain/install. Would fixing the turbine to face the prevailing wind direction (sw) have any positive effect? Or will that create problems/damage? 

BB.

You are very welcome.

You can try adding a larger tail... A few turbines over the years had problems tracking the wind direction because of too small of tail.

However, if simply bolting on a 2x larger tail fin, and it still hunts... You do not have "clean" airflow.

Go back to getting a simple kite and try flying it around the location for your turbine's area, and see how high you have to go to get into laminar air flow (non-turbulent).

If you cannot get the turbine into clear airflow--Then there is no way to harvest any useful energy... It simply is not there in turbulent airflow.

-Bill

XT600

Bill, do you know what the consequences would be if I were to clamp the turbine towards prevailing winds, to stop it from being able to move? This would be a fairly straight forward thing to do, just wondering if it's worth a try before abandoning the project all together...

706jim

Clamp your turbine and then monitor its output. You should be able to discern the results from there. Considering all of your setup parameters I really doubt you will get much more power than required to charge an ipad.

BB.

Is this a "fixed tail" turbine vs a hinging tail to furl in windy/stormy weather? If fixed tail design, I don't see any reason to not try physically point the turbine into the wind (clamp, tie rope to tail, etc.).

Your turbine?

https://futurenergy.co.uk/feshop/airforce-1-wind-turbines/

Just be careful. A turbine spinning at full speed (or out of control) in high winds can be a scary event. You don't want the clamping to cause the mast to fail, and you don't want to risk a tail rope getting caught in the blades, etc...

-Bill

XT600

BB. said:

BB. 

Your turbine?

https://futurenergy.co.uk/feshop/airforce-1-wind-turbines/

Just be careful. A turbine spinning at full speed (or out of control) in high winds can be a scary event. You don't want the clamping to cause the mast to fail, and you don't want to risk a tail rope getting caught in the blades, etc...

-Bill

Yes Bill, that's the one. However, mine has a 5 blade set-up rather than 3, which I believe helps control the speed? I don't have any form of controller/brake system, the rectified output goes straight into a small grid tied inverter. Looks like the inverter needs 22v minimum to start, and so the turbine needs to be spinning quite fast before I get anything out. The easiest way to stop the thing from turning would be to put a clamp around where it attaches to the pole,I hadn't thought of tying a rope to the tail but maybe that's a better option as it will allow it a little movement either way, and maybe a little stretchy rope to give it some freedom but also resistance if you know what I mean :-)

BB.

Point the turbine into the prevailing wind the best/safest way you can.

Regarding having the turbine driving sufficient power to the GT inverter's input... There is not much I can suggest to fix/address poor performance. It is a combination of amount of wind, laminar flow, blade design, alternator design, GT inverter design, etc...

Most of the wind turbine questions we get is that "my turbine is not producing any power"... And there are rarely any successful answers/solutions.

The 5 bladed prop is generally for slower wind speeds. For faster wind speeds, then the 3 bladed may work better.

Remember that power goes with the cube of the wind speed.... For example 18 mph (storm winds) vs 9 mph (around cut-in speed for most turbines), the difference is:

Power ratio = (Vfast/Vslow)^3 = (18 mph / 9 mph)^3 = 8x more energy in the 2x faster wind

From the data sheet (3 bladed 48 VDC model):

They did not give actual output power in Watts @ x.x m/s... But really large numbers based on turbine running 100% of the year at rated wind speed)--Which never happens. Typically a "good turbine system" probably runs at 10-20% of "rated output (commerical wind sites can be >35% of "name plate" rating). So, guessing the real output at 4 and 8 m/s:

Power = 446,000 WH per year * 1/365 Days per year * 1/24 hours per day = 50.9 Watts in an 9 mph wind...
Power = 2,824,000 WH per year * 1/365 Days per year * 1/24 hours per day = 322 Watts in an 18 mph wind...

As you can see--This is not a large amount of energy--And I would not want to see you hurt (or your home damaged) during your experiments.

Please be very careful.

-Bill

XT600

Thanks again Bill, I will be careful, and will let you know if my experiments result in any positive outcomes :-)

XT600

What is your view on VAWT 's ?   Surely one of these would work better in my situation?   Maybe I should be removing the tail, remounting it on it's side, and finding (making?) some vertical blades to fit? 

BB.

VAWTs are worthless. In my ever so humble opinion. 

First, VAWT only are 1/2 as "efficient" as HAWT (1/2 the time "blades are moving down wind, other 1/2, they are moving up wind").

Second, VAWT designs, I guess because of the cycling forces (direction of forces changing during ever revolution)--They seem to be difficult to make ones that won't self distruct over a relatively short period of time (come loose, cracks in sheet metal, blades, etc.).

And third--Folks think that a VAWT will work better in "mixed" wind conditions... Since a HAWT needs to "turn into the wind" to harvest power, vs a VAWT that can "accept" wind from any direction--It would seem like a VAWT would do better in those "turbulent" wind conditions... The issue is that "turbulent wind" has very little harvestable power--So even if one can get a VAWT that "works well", it will not work any better in turbulent air.l

Here is a post from over a dozen years ago that looked at a couple of "professionally" designed and marketed VAWTs...

https://forum.solar-electric.com/discussion/comment/419838#Comment_419838

We do not have many folks here talking about DIY wind turbines... Here are some other sources that can probably help more:

www.otherpower.com (good forum for DIY Wind Power)
Hugh Piggott - Scoraig Wind Electric site for tons of info (from mike90045)
Scoraig Wind "Recipe Book" for DYI Turbines (from Chris Olson... From his 4/11/2013 post)
www.greenpowertalk.org (added from "russ"--Like here but more wind/less solar)

Personally, I am not a fan of small wind. But horizontal axis wind turbines (HAWT) are much better than VAWT at harvesting wind and can be more mechanically  more reliable.

Turbines need to be installed on towers, generally 30 feet or taller to get into "clean air" (60-120 ft tower is better) . Turbines need non-turbulent airflow (above up wind obstructions, buildings, trees). Turbulent air has very little useful energy--VAWT are sold as better for turbulent airflow--But they are not.

Not that I am in the "wind" business--But I have yet to see any VAWT that harvested more that a small amount of energy--And most seem to not harvest any energy at all.

Here is a turbine that seems to match your design--And a fairly large diameter VAWT rated at 2.5 kWatt (circa 2008):

https://www.renugen.co.uk/turby-b-v-2-5kw-wind-turbine-discontinued/

And tested on a 10 meter / 33 foot tower in a "windy region" of Holland (flat land, no buildings/trees/etc.) produced (link to post in thread from 2009 testing of multiple small wind turbines "designed" for urban use):

https://forum.solar-electric.com/discussion/comment/62874#Comment_62874

- Turby (21,350 euro) : 247 kWh per year or an average output of 28.1 watts [24 hours per day @ 365 days a year average]
Power: 2 kW with the supplier an estimated yield of 1485 kWh / year

• Prediction Accuracy: 17% of predicted output

Here is the only VAWT that I ever saw that was submitted to NREL testing... Major structural issues (tall straight blade design) with loose/lost bolts, broken welds:

https://www.nrel.gov/docs/fy09osti/45552.pdf

If you want to experiment with small wind and VAWT--Have fun.

If you want to generate/harvest a useful amount of energy, I highly suggest starting with solar, or at the very least, use HAWT on a 30-60+ foot tower in a very windy location (see DIY links at beginning of this post).

FieldLines has a popular DIY wind forum.

https://www.fieldlines.com/index.php/board,5.0.html

I am not saying "don't do it"--But it is a difficult path to follow.

-Bill