Wind Turbine to heat swimming pool

[oh2flywell]

I would like to use a 2kW wind turbine to heat a swimming pool (using a 2kW in line electric heater) but when the pool is up to temp then divert the surplus to the grid. This sounds simple but is it feasible?

Andy

[Alan]

Quote “ This sounds simple but is it feasible? “

Hello Andy

You would need a control device that only connected the 2 K.W. heater load to the wind turbine once the turbine has started to turn at a reasonable speed other wise the load would not enable the turbine to start turning. This can be achieved by proportional pulse width modulation or by using a direct  ( on / off ) mechanical contactor or a three phase  solid state relay.
Also needed would be a three phase bridge rectifier for either pulse width modulation control or on / off control.

For on off control or pulse width modulation a voltage sensing relay would be required to only connect the heater when the turbine is spinning.

The selection of a grid tie inverter is not so straight forward, there are some to defiantly not purchase. They lack all sorts of features that could have been incorporated in the original design for not much extra cost.

If the grid inverter has not got over voltage input protection the control system starts to get a bit heavy.

How you go about it depends on your electrical / electronic knowledge. Pretty straight forward if you understand the basics. I could help with info on bits for on /off control. If you under stand Pic assembly language I have code written for on / off and pulse width modulation systems.

A post from Paul on another thread.

Re: Grid Inverters, are there any worth buying ?

Suggests  “ Magnatek Aurora. “ inverters. Initial reading looks good but I have no personal experience of the equipment.

Regards

Alan

[Ivan]

SMA have addressed Alan's biggest gripe (and very much a problem on their earlier models). The new box-of-tricks was launched this month - so probably not as bad as it might sound.

I would strongly suggest a rethink. If you have a grid tie inverter, you might as well grid-tie the whole 2kW, and buy it back when required. Because many suppliers will buy/sell at the same price, it will just make life easier for you. If you read Alan's earlier posts, you will see he makes the point that grid tie inverters will disconnect apparently for no reason (actually there is usually a reason, but it's not necessarily obvious), and of course, this is catastrophic if used as a dump load. Also, bear in mind that windy weather often brings down powerlines - when you most need your dump load!

[oh2flywell]

Alan & Ivan,

Thanks for your responses. Grid tieing the full 2kW does seen to make more sense and easier to install. Ivan - can you be more specific about the SMA model and will Navitron be able to supply this as well as the turbine?

Andy

[Ivan]

Can't remember the SMA code off hand. It's only very recently been launched. I like to wait a few weeks before pursuing such items, as often they go through a revision or two once released to the open market!

Yes, Navitron will be able to supply them.


Ivan

[Nick_W]

I would also like to heat a swimming pool with a wind turbine. I considered solar but we are on a very windy site and in the winter, we will not use the pool but will use the power from the turbine to run some electric heaters inside the house to supplement the expensive oil central heating.

I like the look of this turbine:

http://www.energyenv.co.uk/WindPowerKits_5Kw.asp

I guess I'll also need an immersion heater for the pool and heaters for the house.

What else do I need? Can the output of the turbine be utilised in light winds when it's only producing a few hundred watts?

Thanks in advance ... 

[Ivan]

That's the Navitron 5kW turbine. But you'll want the new electronics which we're currently developing...

[Nick_W]

Hi Ivan - what do the new electronics do exactly?

The turbine currently comes with a controller although I'm not sure what it does.

I understand basics like V=I.R and W=V.I and have seen the power curve for the turbine for given wind speeds - but am not sure how the two relate?
I assume that the controller will vary the resistance in the circuit to prevent the heater drawing too much current and stalling the turbine?

[Ivan]

The new elecrtronics are much more sophisticated and reliable. They address many minor faults in the original software, and also allow the turbine to be used for UK grid connection and/or direct heating. It also has a lot of telemetry built in, allows the turbine to be over-driven, etc etc. The list of features would fill two sides of A4. When we release the product, we'll list the technical features of the unit on the website, but not before, as no doubt others will be rushing to copy the ideas!


Ivan

[Nick_W]

Nice. When do you expect to release the updated model?

[Ivan]

R&D has more or less been completed. Just doing some testing/evaluation before we can release it.