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).

• There is no need for artificial aeration in such a small pond unless you have many or large fish in it . Mar 7, 2021 at 14:56

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 Nowadays, almost have been replaced by water pumps.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).

• They are not "lost" they still exist and are sold and used in many places and countries - seen a couple in the UK good when farmers just need water and the field does not have an electricity supply. Also used in Australia and just about all 3rd world countries. Mar 7, 2021 at 8:54
• they had such things in the "western" US in the early or pre-electric times also. Didn't look all that different Mar 7, 2021 at 14:50
• Thank you for this information. I happen to have a personal link to Greece. I'll contact the greek engineer mentioned in the page, just out of curiosity. Mar 8, 2021 at 8:15
• Cabella's sells them Mar 8, 2021 at 19:23

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:

\begin{align}\\ &\text{Ten watt, 12 V solar panel:} &20\\ &\text{Ten amp hour, 12 V battery:} &20\\ &\left.\text{Ten amp, 12 V photo eye or low voltage cutout switch} \right.&5\\ &\text{Five watt, 12 V air pump:} &\ 7\\ &\text{Air stone:} &\ 5\\ &\text{Tubing and wire:} &\ 5 \end{align}