Turbine Size and Distance from House

[Gary]

I am considering a wind turbine to generate electricity for our 5 bedroom house and to heat a swimming pool. Which size would you recommend, I was thinking of the 10kw or 20kw.
If the generator was approx 80 - 100m from house how much power loss would be expected from cabling.
Would this generator supply enough to connect to grid in order to sell any surplus generated electricity back.

gary

[martin]

in theory, yes!
But it does need qualifying - with a 5 bedroom house with a pool, you need a fairly hefty power supply, and probably one of the larger turbines would fit the bill admirably - but you must cost in the mains-tie inverters to the equation - (Around £1500 per 2.5kw) - so if you were going for a 10kw, allow £6,000, for 20kw, allow £12,000.
     The losses from cabling are fairly easy to work out, but again, it does have to be a hefty armoured cable if it's going to be buried, and that is certainly not cheap!
My suggestion would be to firstly sound out your local planners - for a large turbine, there's no question you'd need consent - they are usually friendly and helpful, it makes a pleasant change from boundary disputes!
Having pointed out the above, don't be deterred, the "sums" on big turbines work out extremely well, and you could realistically expect to recoup your expenditure fairly quickly.
If your planners are happy, you then need to choose the best position for it - often the owners of properties "know" the windiest spot from experience, otherwise I'd suggest the investment  in a small weather station - you can then work out pretty accurately where to site it!

[Nick_W]

Heating a pool with electricity does not sound like the most cost effective solution. Electricity is a 'high grade' energy type. You are better off selling the electricity back to the grid and using solar power to heat the pool.

I made a collector using black mains water pipe laid out in a spiral. It cost about 300 quid and I measured peak outputs of 10kw during the summer.

If our pool didn't start leaking like a sieve, I would have built a phase II solar collector for it with inclined corrugated PVC roofing panels.

Remember you are only aiming to gain a few degrees C (for one pass of the water through the system) so the collector can be much cruder than the type used to heat domestic hot water.

[Gary]

Thanks for the comment on solar, I was considering solar, but realistically how many months of the year does it work for in England. The pool is going to be indoor and we are after a means of all year round heat

[Gary]

Martin, for the mains tie inverters do you need to cover the full possible capacity of the generator or just what the average usage to generated difference would be

[martin]

Ideally you'd size for the generator capacity - if you look upon the mains as your "battery", you want to shovel more up than comes down, so you hopefully end up in profit! Sod's law being what it is, you may have a really quiet weekend for consumption (everybody away for the weekend), and it concurs with a nice steady 25mph wind for the whole weekend - you want to have the largest capacity for export that you can get!
Also, if you have a thundering great immersion heater to heat the pool, it won't be "switched on" - drawing current all the time - again, you need the excess to go to the grid when it's "off".
I reckon the best system would be to install sufficent solar hot water panelling to heat the pool in summer, and to provide your hot water needs, then you could probably go for a smaller turbine, because what you're doing is "balancing" the amount of energy used over a year (you may for instance be content with a 5kw turbine, when you'd be better with a 10kw without the solar hot water panels.
Hope that makes sense!

[Gary]

Thanks martin,

that does make sense, on reading about your solar water heating panels they seem a good idea. I think the next step  i s to purchase a weather station and put at the bottom of the field to determine if it is windy enough down there.

Gary

[Nick_W]

Oh it's indoor... It's a bit like wind, asking how much solar gain can you expect. Probably only get an answer by setting up some measuring equipment.

One of the difficulties is working out how much energy you need. If you currently use oil, you can work out how much you are using. 1 litre of oil yields 11.5 kwh - although bear in mind your boiler is not 100% efficient.

Another idea - buying an air/air heatpump could double the amount of heat you get from the electricity vs. using a simple heater element.

If I were to build a housing over my pool, it would only have glass on the south wall and the roof. The north wall would be painted white to reflect sun towards the pool. I would probably still have solar heating but I haven't done the sums or investigated how much solar gain you'll get in the winter...