Wind Generators - Vertical vs Horizontal

gregoinc

gregoinc

Member
Joined
Jan 7, 2018
Messages
274
With minimal rooftop room I have been pondering other options for supplementing power generation. We have more than enough wind, so I figured that might be a complementary source of power.

I have been looking at several vertical axis wind generators, including those with magnetic levitation. I am a complete novice with wind generators, sowas wonderingif anyone else had investigated the options?

I've read vertical is not as efficient as good old propeller blade generation, so am interested to hear what you think? Including wind generation products that you thinkare worth a try. I've seenthere are loads of chinese products available only, but what to purchase?

Thanks for your help :)
 
If you're in a tight area with trees or buildings around, you want to go with a VAWT. It can handle turbulent winds without any issue.

Yes, the VAWT isn't quite as efficient as a HAWT, if the wind is identical. But put them in their own elements where they shine, and they will out perform each other in their respective fields (literally).

A HAWT works very well in open fields with lots of room to allow the winds to settle and more-or-less blow in a straight line.
A VAWT works very well in low areas or near trees/buildings that are within a few hundred feet/meters, in all directions.

So on a farm with no trees around, a HAWT. If near a forest or hills or suburbs, go with a VAWT.

A VAWT built with two moving plates, one with magnets that are turned by the blades and one that has coils below it, is one of the most efficient ways to build them. The discs lay horizontal and turn above the coils (there are some versions where there are actually two discs of magnets sandwhiching the coil disc, this gives higher output)
 
Basically your after a 3 bladed turbine, as long as the tip noise is not an issue. They are the best $/kW and $/kWh value, the main issue is getting a controller that works with the turbine properly. Otherwise a vertical or a 3 blased turbine with a ring around the edge of the blades but these are limited to about 400W due to the size.

A lot of the smaller turbines have nice specifications upto 15-20m/sec and then leave you guessing as to what happens next, only saying turn the unit off (brake/short the output) before a storm (15m/sec a storm ???). This seems to be more down to the use of controllers that do not track the power profile correctly and limit the power draw to the maximum current the turbine can handle, which then over heats as a result of too much current draw (lots of youtube videos of people with burnt out coils and dislocated magnets from overheating). The unit I have has a brake voltage level with no regard as to the current, no other settings available to chage.... which will be used for testing only next month before switching to a different grid tied unit setup that allows the current level to bet set at different voltage levels.

I have not seen any details about what the actual maximum survival rpm speeds are for turbines... but one guy has one in 100km+ winds still running.

The cheap Chinese units that are used on street lights, as a thought, check the last few typhoon paths and see if any of the areas hit had them up on the lights and how many were left working.. off to google...

I'm thinking your not the middle of town ?
 
Thanks for the feedback and info folks.Redpacket I went to the back shed site and found the maglev vertical axis generator, which I will investigate further. Looks good, so maybe an option. I've sought a price on the CXF-600, so will go from there.


image_drbyoi.jpg


Interested in everyone'sthoughts on above?
 
A very temporary test to make sure everything works before trying to put it 11m up on 3 poles (>300 miles away)... 2m diameter, 700W, sets on fire at 900W.. lol..


image_cddntb.jpg


And a completely unconventional setup... still have a small buck, fan array and the manual brake switch to connect.


image_emkgwo.jpg


I had thought that putting a tubine on a hydaulic mast would be better, because when it get's dark you raise it up and before dawn take it down. Nobody would know it is there (appart from the WTF is that noise !!!)
 
I did think it was not an MPPT in any way as it seems to just charge based on the voltage waveform... starts charging when the AV input is ACvolts / SQRT(2) - i.e. it starts charging as soon as the peak voltage goes above the battery voltage, so just connecting to the battery directly.

Loads of "MPPT" controllers on eBay and Ali are anything but MPPT. Maybe Maximum Purchase Price Testing... so had to open it up...


I stand corrected, as there is one inductor tucked in the back of the unit and another componet I can't figure out what it is, although the inductor is probably for the solar, so will have to test that next month. I took one of the ends off the case to have a peek, can't see the traces on the PCB so have no idea as to the wiring layout internally. The other end I can't fit a screwdriver in the gap to open it up.


image_xnqukk.jpg
 
You'll get very very poor results using a controller like that with a WT, unless it has a user definable option to manually enter a power curve.
 
Yep... not ideal. I was expecting at least one or two settings and not just a "brake voltage" which is not really a setting, more like "at what voltage level do you want your turbine to burn out at ?" sarc...

It will likely end up as a backup unit.
 
You mean break voltage.

Inverters designed specifically for use with WTs aren't MPPT, it's you that enters the numerous (at least 10 idealy) current/voltage points, which the output will track. Get that wrong and the turbine will either stall or overspeed.

A solar MPPT inverter will attempt to automatically find the maximum power point, which varies - the output of a WT will be fixed (found either by design or experimentation).


image_mwfsql.jpg
 
LOL.

The only wind controller I have found so far that allows settings by voltage and current are the GTIL 1kW and 2kW models but they are grid tie only and not sure what the losses are at no generation or little generation. For a small 700W unit with average output around 100-200W losses of >20W would be significant. Also not sure how these behave if they lose the grid connection... if they unload the turbine to spin to destruction.

In theory a wind MPPT controller can learn the turbine characteristics and track the voltage up rather than with solar tracking the current down.. not sure if any out there can or do this already ?
 
There's no such thing as MPPT in WT inverter design.

When the inverter unloads, perhaps due to grid loss that's when the over voltage protection (which is external, and electrically before the inverter) kicks in the dump.

Outback have some kit that allows rudimentary settings for WT use with DC charging.
 
Chiming in late on this one, sorry. I have a 3.5kw VAWT for 3-4 years now and it works pretty well. The most power in one day was 29kwh, typically 6-10kwh 250-500w on average, its a good supplement to our power though as we are at 53* north.
A few points:
In urban areas a VAWT might be safer in the case of mechanical destruction. A friend has a 6Kw HAWT and it threw one blade 300m!
HAWT's are 20-40% more efficient but can be crazy expensive because of the management circuits needed on some machines. 35k in one case for a small machine I know about.
Dont consider any turbine unless you have a very good site or you will be disappointed.

Good luck.

J
 
SemaJG said:
I have a 3.5kw VAWT for 3-4 years now and it works pretty well. The most power in one day was 29kwh, typically 6-10kwh 250-500w on average ....
Click to expand...

What's the manufacturers name ?
 
You must log in or register to reply here.
Back
Top