I have a customer with a large wind generator, high in the pennines and whenever I visit it is whistling away.
The control system "dumps " surplus power via a large heater element on the back wall. The oiler fired Rayburn 368K is not sufficient to heat the house and supplementary heating is needed. It occurs to me that a couple of good sized commercial immersion heaters in an accumulator tank could let the excess energy be utilised. The house heat losses will be high on a windy day when the machine will be producing too much power so feeding it back into the house seems logical
Does anyone have experience of this type of installation or links to any useful sites?

On the previous forum I read about a home that was off grid and using a 6kWh wind turbine, when it was producing to much energy they dumped it into night storage heaters, seemed a very simple solution which I have never heard an "expert" suggest, might be worth a go?

I think I'm the person with the storage heaters which Peter A mentioned.

We have a Proven 6kW wind turbine. We've installed three storage heaters and one convector heater to use up surplus power, and are soon to add more to the system. There is a failsafe coil attached to the wall in the control shed, which rarely gets even warm.

Some people use the immersion heater system, but that disperses the heat over the whole house and only results in a small increase in heat. Our system focusses the heat where it is most needed.

If the original poster would like to have a chat about what we did here, email me on info at peafowl dot freeserve dot co dot uk, and I'll send over my phone number. Make sure you put something obvious in the subject line, though, as we get a lot of spam which we delete without hesitation!

We were amazed that no one else had really investigated it. Even Proven (who made the wind turbine) were not sure it would work, but it has, and very well.

I'm assuming that John's client is off-grid... in which case, warn the client to ensure their control box is wired up correctly. We had three system fires, two of which were caused by Proven wiring things up wrongly... they tried to blame our storage heaters, but eventually managed to prove that they'd done it wrong to start with. They're not used to dealing with off-grid installations, and with our one, it showed.

By the way: you can have up to five dumploads (we intend to add another) and as storage heaters don't keep drawing power once they're as hot as they can get, we're going to wire in further storage heaters for next winter which come on once the original ones get full up. Hope that makes sense. Ours is a very windy location, so I can't guarantee everyone else will need to do that, but it'll be worth it for us.

We're also wiring our rainwater collection tank so that the water is only pumped from the tank when the dumpload is on... it won't make much of a difference, but it'll make us feel smug. Which is important.

And we heard today that we've been shortlisted for the Yorkshire and Humber Microgeneration awards so either our storage heaters are considered a generally good thing by more than you and me, Peter, or there weren't many entrants. I'm hoping it was the former.

i suppose i should really start a new topic here - but we have just had a proven 6kw turbine put up - and we are wondering if there is anyone that is selling their surplus power at more than 4.5p per unit. seems v.unfair that to buy it would cost 11p per unit! obviously we are still connected to the grid.

Thanks for all your comments folks.

I am not sure of the capacity of this rig but 6 Kwh would sound about right.
It is indeed off grid so there is no buyback option. I bet the windfarms are getting more than 4.5p for one of their units so that rate does seem a bit unfair. Having said that I presume it can only be used locally without processing costs to step it up to distribution voltage.

I am particularly interested in the using the output for water heating as there is a full wet system in the property, albeit that the boiler has insufficient capacity. I see it as a way of boosting the output of the system for little extra fuel cost.

The house is a large tied farmhouse with a single occupant, his duties oblige him to live there but he does not use electricity for much more than lighting. His employer is prepared to fund the upgrading of the system but it seems mad not to utilise the surplus power. I could incorporate an electric boiler but this would mean using the heat immediately unless an accumulator tank was incorporated.

As a heating engineer I am opposed to the principle of storage heaters in that they cannot be adequately controlled .
They heat up when power is available and give off the heat in at a progressively reducing rate as they cool.
I recognise that we are talking about free energy here ,in that if it were not put into the storage heaters it would be wasted in the outside air, but we are hoping for a solution which permits us to release the heat at useful times, rather than when there is no-one at home to enjoy it.

If you'd prefer to use the wet system then that's the most usual way to go. An immersion heater is installed in a piece of fat pipe (drainage pipe?) to replace part of the existing pipe run, usually just before the boiler. Add a thermostatically-controlled pump which switches on when the water around the immersion heater gets hot, and you're done. With the Proven you can have up to five dump-loads, and so five immersion heaters. If going this way I'd have preferred to have the immersion heaters fuelling a tank, rather than the fat pipe method, to give some storage, but the fat pipe way is the most usual. So I'm told.

Can you let me know who installed the wind turbine? It seems odd that this hasn't been looked at. If this is a Proven 6kW, as ours is, then who ever installed it should have dealt with the dump-loads at installation, and it's ridiculous that they didn't. However, there should be relays in place in the top right-hand corner of the wind turbine control box which will control the dump-loads, but make sure these are wired in correctly--it was these that failed and caused one of our fires, as they were feeding power back to the other dump-loads and so overloading them. If they're not present, contact Proven about getting the control box altered--they should handle all that for you. If it would help to come and look at ours you're welcome.

Regarding selling your power, from what I can make out, Good Energy offer 4.5p per unit to off-grid micro generators. The payments are based on estimated generation i.e. it is not metered:-

http://www.good-energy.co.uk/home_gen_varnom

So far the discussion has been around using surplus electrical energy to generate heat.
Heat is a relatively low grade form of energy which is pretty much where it all ends up anyway (isn't it?)
Would it be better to consider using surplus electrical energy to drive you fridge and or freezer?
They are two considerable electrical loads which can have a considerable amount of freedom as to when the energy is applied (but we rarely take advantage of this).
How about organising a separate insulated cold box, filled with water just above your fridge.
In times of surplus electrical power, use it to freeze the water to ice. Organise a secondary circuit of some suitable fluid (no idea what) which circulates between the ice and the fridge. This fluid doesn't need to go through the normal compress, cool, expand, heat cycle of a fridge, it just needs to remain liquid at a temp. lower than you ever get your ice down to (salt water?). As long as it has normal bouyancy it will move heat from the fridge (at 5deg) up to the ice (at -5deg), or more importantly it will move coolth in the other direction.
It needs lots of energy to turn ice at 0deg into water at 0deg, and all this will be drawn from your fridge, thus keeping it cool.
No idea how you control the flow of heat from fridge to ice, maybe just a simple throttle on the circulating liquid.
You could probably do something fancy with the heat you suck out of the ice, or maybe you could keep the ice outside the house insulation layer and have a longer secondary circulation system which passes through the house insulation layer.
Electrical is too good to just to dump into water as heat.
Cheers.
Geoff.

John, 5 months on from the last entry I presume that you'll have moved on but wondered if you looked into Phase Change Materials for the heat storage?

Ian