Monday, May 17, 2010

The Watermotor: renewable energy for poor rural areas

This interview I conducted with Ron Davis, designer of Campo Nuevo's watermotor: a small scale hydro motor that he designed to help with development in poor rural areas that lack access to the electricity grid.

Ben Courtice This is Ben Courtice and I’m here at the World Summit on Climate Change and the Rights of Mother Earth in Cochabamba in Bolivia, so here I’m talking to Ron Davis who has designed a water motor which he is advocating as an appropraite technology for sustainable development. So Ron, if you could introduce yourself.

Ron Davis I’m Ron Davis and I designed a small turbine that can be used to directly power machines.

BC So in history we’ve seen a lot of water wheels and hydraulic power used. It’s not necessarily the newest technology around. But certainly this one looks promising. Could you explain how the history of the water wheel has influenced your design?

RD The water wheel was humanity’s first natural energy and the source of most modern technology, mechanical technology, comes from the use of the water wheel. Over a period of at least 2000-2500 years.

BC How far across the world has the water wheel, the ancient, traditional water wheel technology been used?

RD The most common ancient design water wheel spread almost around the entire world. Even today there’s examples of the ancient water wheel still in use here in south america.

Ancient water wheel design
An ancient water wheel

BC So you have designed this water wheel that you call the water motor, or hidromotor, and what have you changed from traditional designs or other industrial modern designs of water wheels to make yours?

RD Basically I’ve gone back to the traditional design. I’ve sort of, you might say I’ve re-invented the wheel. Or the water-wheel. And what I’ve done mostly is adapt modern technology to use the water power directly rather than to make electricity.

BC In terms of the construction of the models you’ve got here on display, the Pelton, what’s the name of the more common water wheel we see?

RD The most widely known small hydro wheel is the Pelton. I’m using an improved version of that called the Turgo wheel, but actually it’s not a new design, it goes back at least 500 years. There’s examples, and drawings of examples, going back to before the year 1600.

BC So the Pelton has limitations in it’s capacity based on the direction of the water flow against the blades of the wheel, is this correct?

RD The Pelton tends to … well, we’re getting into technical things here, but this is an improved version of the Pelton wheel. It can use far more water than the Pelton can. So the same size wheel will produce more power.

Campo Nuevo's small watermotor
BC The two you have on display here – you’ve got one smaller and one larger – would you like to tell us the size and the power output for our listeners to get an understanding?

RD The small one is capable of running most machines that are driven by mid-sized electric motors. This turbine that I’ve built can be used in place of electric motors – stationary electric motors – in most machines.

BC The larger one I think is 150mm diameter wheel, is that correct?

RD That one, my basic model, is capable of producing twenty horsepower, which is far larger than most electric motors.

BC And because you don’t try to go to electricity, you directly drive the machine, it’s actually very efficient. Do you know what sort of efficiency loss you have in this motor?

RD These turbines are 80-85% efficient. And that’s a big advantage, because the efficiency, when you’re using direct drive, you maximise the use of the available water and water power that you have. And so you don’t waste a lot of the energy in converting to electricity and then re-converting back to motor power. Though also it has limitations, that you have to drive the machine from a location, well basically where the turbine is located.

BC If you were to use this to generate electricity, what sort of output, how many watts output would you get from it?

150mm watermotor turgowheel
Larger watermotor

RD From the larger turbine you would get around 12Kw of electricity.

BC You’ve successfully marketed these to some customers, they’re in use around the place, maybe you could just give us a run-down on some of the applications that your wheels have been used for?

RD Well, some of them are used to generate electricity, because the watermotor does that as well as any other turbine. What I’ve done is invent a power control system, and as far as I know it’s the only turbine that has an instant power control system so that the turbine can be switched on and off just as an electric motor. As far as the uses go, they range from peeling coffee in Nicaragua to plucking chickens in Ecuador.

BC To make one of these wheels, Turgo wheels, part of the idea is it’s appropriate technology for development that can be used in poor countries, what sort of industrial resources does someone need if they were to start building their own, if the idea was taken up?

RD Well, I designed this turbine to be made in a small shop with locally available materials, with common technical ability.

BC You need a basic small foundry, a small machine shop, a bit of welding capability, is that roughly it?

RD Yes. You need a small amount of lathe work and to make the actual turbine wheel you need to be able to cast aluminium or bronze, in small pieces, of aluminium or bronze for each of the blades of the turbine, and then the turbine is assembled from these castings.

BC And the control system looks like it might need something a little more complicated like a milling machine, is that correct?

RD No, the control system needs to simply be carefully made, it doesn’t require any special tools, a hacksaw and a file.

BC That’s pretty easy for most people to get hold of I suppose! Are there any other applications that this could be taken up for, or that you would like to see it considered for?

RD The idea of this, the reason that we launched into this project, was that especially here in Bolivia, people that live away from the electricity grid, which is almost probably 85% of the country or more, they have no way to produce things they need locally, because they don’t have machine power, and the lack of machine power is one of the chief causes of rural poverty. So with the watermotor, if they happen to have a small fast-flowing stream nearby, they’re able to use the watermotor to produce items that you normally need an electric motor to produce. And then, besides that, there’s crop processing, like peeling coffee, chopping fodder, various agricultural products.

BC Using a fast flowing stream, you’re not actually polluting the water or the air or anything, this is very renewable technology isn’t it?

RD That’s right, it actually improves the quality of the water because it’s aerated as it goes through the turbine, oxygen from the air is introduced so the water is actually improved somewhat, and as it turns it uses no water, in reality it uses no water at all, it uses merely the energy from the water and the water is returned to the stream.

BC Roughly what sort of water flow do you borrow from the stream, how many litres per minute, and how many metres of drop do you typically use in these applications?

RD We usually talk about 15 meters of pressure, that is the water enters the pressure pipe 15 metres above where the turbine is situated, and the quantity of water can be thought of as enough to fill a four-inch pipe or 100mm pipe, and the volume being from 200 litres a minute on up, to a thousand litres a minute.

BC You hold a patent on this technology in Bolivia, but what’s your attitude to other people using it? They can order from you can’t they, but are you happy for people to build this sort of thing themselves?

RD Well, this is an appropriate technology design, and so by definition I built it to be in public domain. The only part of it that is patented, here in Bolivia, is the control system and that was patented primarily to prevent other people from taking it over and claiming it as their own, which unfortunately happens all too often in this world. The rest of the machine, the basic turbine and turbine wheel and so on, it was designed to be copied. Each one of them I offer as an encouragement to be copied.

BC And can people get the design plan to build their own from your website?

RD Well the design itself is not on the website. I would suggest that they buy one and then copy the one that they buy. I think that would be a good idea because I’m trying to make a living also!

BC That’s fair enough! We’ve given a bit of an overview of this technology and people can look at the website as well, do you just want to tell people the web address?

RD OK, the website to see the watermotor, and information about the watermotor, is simply – that’s the website. They can see the watermotor in action, actually the very first watermotor, is shown in action on YouTube, at an address of watermotorturbine, one word.

BC Is there anything else you want to add to the interview?

RD I want to send my regards to the people of Australia, and I hope that somehow this can be of use to someone there.

BC Thanks a lot for that, Ron.

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