Small water pump powered by wind turbine : what type?

Question

I need to aerate a small pond in my garden. I would like to build an autonomous system with a small water pump. The power would come from a small vertical wind turbine I will build. Since my pond is tiny (only 150 L), I will only need to pump small amounts of water, that too at a low height (20 cm is enough). The idea is to make some sort of a fountain.

The pump would only have to work when there is wind, because the pond is capable of staying in good shape without constant aeration by design (lots of plants, no fish). The flow rate could vary depending on wind speed.

I see two options :

1. make an all-mechanical system, with the windmill directly powering a mechanical pump,
2. make an electric system, with a windmill producing electricity (say, 12V) to power an electric pump.

For option 1, I would prefer to keep the design as simple as possible. Ideally I'd connect the pump directly to the shaft of the windmill. Since I know nothing about pumps, I'm wondering what type would be suited for this option. I assume that it would have to be able to pump from low speeds, and its torque would have to be fairly low (my wind turbine is going to be quite small). I was considering this, but the manufacturer says it needs 600 W to work.

For option 2, I'm worried about the fact that the pump might receive power on and off a lot, and I assume (perhaps wrongly) that these motors like to get constant power. If that is not a problem, then I'd probably get a small waterpump (like this).

Any advice welcome.

Answer 1

Regarding the mechanical solution, there is a lot of lost technology.

From 1910 to 1950, in a plateau in Crete about 800[m] above sea level the landscape looked like this:

Each of the windmills is a mechanical water pump system. The cost and the technology was very low level (I don't know exactly what was used). Nowadays, almost have been replaced by water pumps.

However, I found out while looking that there was a European Union Cultural Heritage project, aimed at restoring and reuse the technology.

You might be able to find something more from that project.

PS: I decided to post this although strictly speaking, all I'm doing in pointing to a site. I will look into it, and update this later on (hopefully).

Answer 2

The mechanical option uses a simple crank turned by a low speed rotor. This has a tail to keep it in the wind and the tail can "fold" if the windspeed gets too high - depends on the design.

The complete device is of simple construction so that repairs can be made with basic tools. No computers used for speed control, direction etc

There are still made and commercially available water pumping windmills.

This is one site found after a quick search:

enter link description here

Answer 3

The simplest system for a low speed turbine is to buy a piston-type fluid transfer pump from harbor freight for $6.99 and work its piston up and down using a connecting rod that goes up to a crank throw on the turbine shaft.

For a higher-speed turbine (3-blade, for example) you can readily buy for a few dollars a small rotary fluid transfer pump that fits into an electric drill chuck, and you then spin the pump shaft with the turbine shaft.

Answer 4

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Answer 5

Yes, you can use a 12v alternator for the generation of the current. As you have specified the fluctuating load can cause issues, so to overcome this a variable voltage motor can be used which are used in bicycles and bikes example "Ebike MY6812 120W 12V 3350RPM DC Electric Motor for Bicycle". They are cheap in cost and can power a small pump easily. You can use a simple 12v submersible pump which can convert the power into high head water rather than high volume. I will suggest adopting an electrical method for aeration of water, as water has to be sprayed with a lot of head in the air which can help the water to be aerated. This system can be flexible and can use for other purposes like lighting, etc. As the pure mechanical method may pump high volume but it won't provide a high head for the aeration. Also mechanically pump will require more attention and maintenance. Another advantage of the electrical system will be the flexibility of the location. As compared to a mechanical system, the electrical system can be placed on the rooftop as well as any higher location, where it can receive enough wind to run itself. Addition of few more features like tail wing/guide wing. The tail wing can guide the turbine in the direction of the wind. This will help better and stable production of power irrespective of the direction of the wind. Also adding this may add up the price to the system because it will require bearings and structure to support the changing load conditions. Also, you can go for the vertical turbine as they can work on the wind coming from any direction. The vertical turbine can also save space for and mostly it looks cool with the pond. Coming to the mechanical pump. The mechanical pump can use for watering the plants. If you have a tight budget then I would suggest using this method as this is the cheapest type you will find. Also maintenance can be done using simple shed tools like hammer, wrench, plairs, saw, etc. The mechanical system will provide a better advantage to the volume which can be pumped using the same amount of setup. As you can use crank setup the machine can utilize its maximum power. Please make sure you have the least friction between the moving parts. The mechanical system can also benefit from waterproof issues as it won't require any waterproofing solution. This will reduce the cost of the system as well as make it more prone to rainfall. If you want a simple setup idea You can use a poll of height ore than 3-5m. Please make sure the poll is strongly attached to the ground with enough support to withstand a good amount of loading conditions. Next, you can use a bearing and fix it with the poll end using some sort of plate or holder. Please make sure the bearing is horizontally aligned as the slightest angle may cause imbalance and more friction between the parts. You can use a simple 12v generator and mount on the bearing and attach a fin/tail wing at the end. You can use 3 blades with lengths more than 1000mm for good results. You can use the power produced for the pumping purpose