Wind turbines and space heating

P. Breathnach

For almost all households, the greatest use of energy is heating the home.

I have read some stuff on wind turbines (including on this forum), and the big issue is that the energy generated is not constant so it has either to be stored using large battery installations, or sold if somebody will buy it. Neither seems to me to be an outstandingly good solution.

The idea that interests me is using storage heaters in conjunction with a wind turbine. Perhaps my research skills are deficient, but I have not come across a discussion of that topic anywhere. Yet to this not-very-technical person it looks like a candidate for getting good value from a wind turbine -- in the winter months, anyway.

Has anybody here got knowledge or thoughts on such a proposition?

von Neumann

Interesting idea,

Direct conversion from mechanical energy to heat would be difficult,
Maybe you could use friction plates (brake disk) to heat water. I've know idea how effiecent that would be but it's an option.
Maybe it could just be bolted on to a solar heating system.

The simplest way would be to convert electical energy and attached an heating element.

Just think out loud.

P. Breathnach

I was thinking along slightly different lines: wind turbine to generate electricity that is fed into electric storage heaters.

Okay, I know that there is energy loss in the two conversions, mechanical to electrical, and then electrical to heat. But it is using established technology, and is therefore more likely to be reliable. And it is a technology that can, to a great extent, cope with the fact that wind is not constant.

[The other possibility -- but one that I suspect is unworkable -- is to use motive power from wind to drive a heat pump.]

von Neumann

Ok I see where you're coming from now.

I can see the potential now.

Would you have a standby system for heating?

How big a turbine are you looking at?

I suppose the only question I would have is current loading / management?
Storage heat would require a high current load? (Not my area of expertise).

P. Breathnach

Yes, I'd have a standby system -- the existing gas-fired system.

I'm not yet looking at a turbine. Given the rules as I understand them, I can just about get a worthwhile system onto our site -- perhaps 10 m. high and 2m. diameter, that sort of scale.

I think typical storage heaters when installed on nightsaver systems draw about a 3Kw load over about 8 hours, but that's not my area of expertise either. I have no idea how they might perform on lower power, or if they would be any use at all.

slagger

From a rating perspective under the new Building Energy Rating scheme storage heating gets the worst rating over the likes of oil and gas. This has to be considered if you want to sell or rent your house.

P. Breathnach

Yes, storage heating is a bad idea if it uses mains electricity because of the gross inefficiency of using fossil fuels to create motive energy to generate electricity to convert back to heat. A bad deal for the consumer, and a worse deal for the environment.

But the chances of anybody installing a wind turbine for a house they wish to sell or rent are, I think, close to zero.

slagger

Come to think about the BER does allow for renewable methods in the rating scheme, so if you have a turbine generating the electricity it should help to offset the rating on the storage heaters.

baldieman

P. Breathnach wrote: »

Yes, I'd have a standby system -- the existing gas-fired system.

I'm not yet looking at a turbine. Given the rules as I understand them, I can just about get a worthwhile system onto our site -- perhaps 10 m. high and 2m. diameter, that sort of scale.

I think typical storage heaters when installed on nightsaver systems draw about a 3Kw load over about 8 hours, but that's not my area of expertise either. I have no idea how they might perform on lower power, or if they would be any use at all.

Unfortunately, 10m high and 2m diameter would require an exceptionally good/windy site, along the south or west cost perhaps? in order to get the kind of power your looking for. Perhaps twice that diameter and 15m +

P. Breathnach

baldieman wrote: »

Unfortunately, 10m high and 2m diameter would require an exceptionally good/windy site, along the south or west cost perhaps? in order to get the kind of power your looking for. Perhaps twice that diameter and 15m +

You are probably right, but I slipped up because I meant radius when I wrote diameter. I can't go higher than 10m because of the space I have available. I think that we have fairly average wind where I am on an inland site that is fairly open, in particular to the SW. My guess is that I can get a max of 2 to 3Kw, but I haven't much idea of what the average would be.

Apart from cooking, we don't use anything that consumes a lot of electricity (low-energy bulbs, etc). So any wind turbine would produce more power than we need, even without considering the probable mismatch between availability and demand. I would be happy, however, to reduce gas consumption.

What I hope to learn is whether the idea is worth investigating further, or if it is so far off-beam that I should drop it.

baldieman

The problem with any of this is, it's trail blazing. Perhaps in twenty or thirty years time the different technologies will come together and there will be great systems available. But today, cost effectiveness is not there. You've got to want to do it!!
In order to receive 2 - 3kw you need about 8 - 12kw rated machine.
4m diameter? not bad but I don't think quit there. Even if you do get that power, what do you do with it in summer?
Having said that, a 3 - 5kw 24v or 48v machine can give great back up power using batteries and dumping the access power into heat is in my view, a good way to go with present technology.

air

Using wind for heat is not going to be economic, you'd be much better off planting some trees to burn or whatever. Spend your money on improving your insulation.

pkmwgs

i have a 6kw turbine connected to a series of heating elements in a 500 litre tank linked to a heating system. rotor diameter is 5.5 metres.
backed up by 8 metres of solar tubes.
used no oil since march. 13500 killowats produced in one year.
expencive system, but self install. the tank acts like storage heaters but far more efficent.
this any help.

baldieman

pkmwgs wrote: »

i have a 6kw turbine connected to a series of heating elements in a 500 litre tank linked to a heating system. rotor diameter is 5.5 metres.
backed up by 8 metres of solar tubes.
used no oil since march. 13500 killowats produced in one year.
expencive system, but self install. the tank acts like storage heaters but far more efficent.
this any help.

Now that I'd like to see!! What voltage? Are you also charging batteries or connected to grid? where did you get the machine?
I have a small Hugh Piggott machine 500w works well charging batteries and about 3M of solar thermal for DHW.
I'd like to build a bigger machine perhaps 24 or 48v 16ft diamator

Oldtree

So would I. It sounds great. Is it direct from the turbine to the hot tank? If so how? Would be very interested to hear about the preformance over the winter. Can you tell approximate costs. What is the orientation of the solar panels and the height of the mast?

Oldtree

The only thing i have been able to find along the lines of what I would like to achieve is on this page:

http://www.truenorthpower.com/index.php?option=com_content&task=view&id=56&Itemid=24

We've recently experimented with a new system at the FREE Wind Test Centre using the new AEROMAG/LAKOTA turbine controller, that manages the load "automagically" without the need for batteries. The turbine shown running here at the test centre has been working through some pretty tough winter storms the last few weeks, 30-40mph winds for days at a time. It is not connected to anything but a 24 volt air heater that heats the sign . . . not a very good use of power . . . but hey it's just a test. The secret is in the new controller that "steals" just enough energy from the turbine to maintain a set voltage but not enough to let it stall or too little that would let it get out of control. Turbine $2,645, Tower $990, Heater $150, Installation $800: Total cost $4,585. Now the cost of energy paid off over 10 years is below current utility costs and as the utility price goes up the payback period is shorter. You can't get that from the family car or an energy efficient appliance. Use two turbines for twice the energy at $7,800 cost and over 20 years each kWhr costs less than 4 cents even accounting for maintenance and repairs. Are you ready . . . that's ONE THIRD the cost of today's energy.

Can it work?

air

pkmwgs - What kind of a controller (if any) are you using between the turbine and heater elements?

pkmwgs

Hello,
The turbine is a 300v proven on a 15 metre mast, grid tied through an sma windyboy inverter. solar panels are facing directly south and still working away.
yesterday it raised the tank temp from 40d to 65d celcius.
there is a 20 ft diy job with pictures on the homepower site that looks well built, you would need a lot of spare time and an understanding other half.

air

Hiya, Thanks for the reply.
Ok, so I take it that the Windyboy is acting as your charge controller. How does it decide when to dump energy to the immersion? Does it take a temperature input from the immersion? If you dont mind me asking, what was the connection cost for the generation connection to the grid and what rate do you get for the electricity you generate?

pkmwgs

Hi,
The inverter connects straight to the grid, smart meters are currently on test (pilot scheme) so no payment for extra eleltricity down the grid.
It cost nothing to connect to the grid just a lot of paperwork. i have a display on my kitchen window that tells us what power the turbine is producing so you can put immersion heaters on and off. basically you are the controller in that respect.

air

Cool, so you're part of the SEI pilot scheme then and just turn on your immersion heaters manually whenever you have excess wind energy to use. Sounds sensible if you're not getting paid for the excess. Perhaps you could get a controller to do this automatically for you? Seems a shame to give the ESB free power if you're not around to switch on the immersion.

jobrok1

I know this is basically a thread about grid-tied / heat producing wind turbine systems but I have a question (probably stupid, but anyway!) on off-grid systems.

If I have a 12v micro turbine charging system in place, with a bank of say 4x12v batteries. Is it possible continue charging with 12v, but to then draw power from the batteries through a 24v inverter.

I know this means having all 4 batteries in parallel for charging.
But is it possible to also wire 2 sets of batteries in series for 24v and then parallel these 2 sets to power through a 24v inverter.

Will this completely fcuk my batteries?

Someone out there will set me straight! I'm sure.

air

No, none of what you propose is possible. You could use a DC-DC converter to produce 24V from the 12V supply but you'd be much much better off buying a 12V inverter, they're cheap as chips.

jobrok1

Yeah! I kinda knew it wasn't possible.

Just needed to be told.

rubadub

air wrote: »

Spend your money on improving your insulation.

And the cheapest increase in insulation is usually your own personal insulation, i.e. more clothes. In my workplace it is often so hot people are in t-shirts during winter. This changing from cold to warm environments is also supposed to be bad for health.

Also people themselves are giving off heat and can heat a room. Many will have a large sitting room warmed up, while they just as easily sit in a smaller TV room for the night. Those really serious about it should be wearing hats indoors.

I had space heaters in my last place but we were never at home during that time, it just went to waste, we were better off with timed heaters to arrive home to a warm house. Also most units on standby are simply giving off heat, if you have a thermostatically controlled heating system then it is going to switch off when warm enough, i.e. the energy saved from the appliances turned off completely will be pretty much offset by the extra energy used by your thermostat. But only really in winter and if your heaters are on all day.

badolepuddytat

tied to a heat pump you would get 3-4 times the heat out of your turbine.....

....expensive though.

turning high grade energy (elec) into low grade (heat) is just wrong from a design point of view.... hense storage heaters are peanalised so much in BER.

P. Breathnach

I'm not getting a great deal of encouragement!

Yes, the best policy on heat includes reducing the amount needed. We already have a high standard of insulation, although I intend to add more in the attic. I agree about personal insulation, and I do wear warm clothes indoors so that the amount of space heating needed is reduced.

My target is to achieve that space heating in a sensible environmentally-friendly way, one that is not ridiculously expensive -- although I would pay a moderate premium in order to do what is best for the environment. That is why I wondered about a wind turbine as part of a solution.

I don't quite accept your point, badolepuddytat. Storage heaters working on electricity provided through the national grid are a bad thing; I'm less sure that storage heaters working on electricity generated without consuming fossil fuels are bad in the same way. Perhaps ineffective.

So if my wind turbine/storage heater idea is not a runner, has anybody got any other solutions to recommend?

DragonT

Hiya,

I was just thinking you guys might want to give this site a glimse:
http://helixwind.com/
This seems to be ready to go and is actually a vertical system for wind power generation.
5db is the noise output which seems to be fairly low and it operates starting at 8mph winds ( 3.2 m/s i think ... ).
According to the tech sheets it will output arround 3 - 3.5 kWh/year at an average rate of 8 - 8.5m/s winds ( this is the lowest average speed on the irish wind map I found for my area.) ( http://helixwind.com/en/factsheets.php )

What do you guys think ? Might be something arround all these legal / safty /enviromental issues still hanging arround for the regular wind generators.
Oh the size of space used to install : 3.19 m2

This seems to be a good candidate to be combined with any heat storage system as well, as it operates at low speed, or not ?

Cheers,

Dragon

DragonT

http://www.esb.ie/esbnetworks/generator_connections/index.jsp

This is the webpage that actually was not easy to find for me, but they provided it freely.

Rgs,

Dragon

von Neumann

Hi, In a previous life I looked at this type (vertical) of turbine in detail.

Areodymanic - effecient
Mechanical / Structural - Poor
Electically - No Comment

My advise would be make sure you have a good local contact point if mechanical issues arise and a copper fastened warrenty to go with it .

DragonT

von Neumann wrote: »

Hi, In a previous life I looked at this type (vertical) of turbine in detail.

Areodymanic - effecient
Mechanical / Structural - Poor
Electically - No Comment

My advise would be make sure you have a good local contact point if mechanical issues arise and a copper fastened warrenty to go with it .

Hi,
Thanks for your reply. Would you be able to explain why you are thinking that the Mechanical / Structural is poor for VAWTs in comparism with the regular HAWTs available ?

Would better aerodynamics not mean less vibration and would that not mean less problematic joints/bearings, besides the better effecienty ?

I guess the electical bit is defined by the generator connected and the rest of the connections and installations seem to be standard installations also required for HAWTs.

Any comment would be much appreciated.

Rgs,

Dragon

von Neumann

Mechanical the issue comes back to ther bearing design.
This bearing is placed under some pretty difficult stresses in operation.
These stress increased dramatically if the shaft and blades become unbalanced even if only by a few mm.

They may well have found a way round these issues but many of these issues would not be seen unless accelerated life testing has been done, and even this would be difficult as it would not be easy to reproduce an accurated estimate of likely life time stresses / loads.

I'll stop here while we're all still awake :eek:.