While Australia has a couple of wet years drought may have receded from many of our thoughts. But no doubt it will be back. Some renewable energy technologies that have just come to our attention this week also display ingenuous ways of obtaining potable water in dry environments.
While Port Augusta is in the news for renewables, let’s look at the first report, from RenewEconomy, of the giant solar-thermal powered and watered greenhouse there:
South Australia’s Port Augusta, with its abundant solar resource, has recently been pegged as the ideal location for the development of a concentrating solar thermal power plant – and understandably so. But what about a 2000 square metre greenhouse? It would seem an unlikely match for hot, dry Port August, yet while the region’s CSP plant proposal remains just that, an enormous solar-powered greenhouse has indeed been built – and it’s producing a fine crop of tomatoes.
Behind the project is Sundrop Farms: a group of international scientists (and an investment banker) whose goal has been to devise a system of growing crops that doesn’t require a fresh water supply. How does it work? “It all begins with a 70 metre-long stretch of solar panels,” says Pru Adam’s on ABC Radio’s Landline: a series of concave mirrors which focus the sun’s energy onto a black tube that runs through the centre of the panels. The tube is filled with thermal oil, which is superheated up to 160°C, then pumped through the tube back to a little storage shed, where its heat is transferred to a water storage system. Some of this stored heat goes towards greenhouse temperature control, some to powering the facility, but most is used for desalination of the tidal bore water. When the heat goes to the thermal desal unit it meets up with relatively cold seawater and the temperature difference creates condensation.
“It’s pretty simple to understand,” said Reinier Wolterbeek, Sundrop’s project manager and head of technology development, in a 2010 television interview with Southern Cross News. “If you have a fresh water bottle from your refrigerator, and you put it in a room, then condensation forms on the sides. That’s more or less what we try to mimic over here; the cold sea water, from the ground, we put it through plastic tubes, we blow hot, very moist air against these plastic tubes, condensation forms on the tubes, we catch the condensation, and that’s actually the irrigation for the tomato crops.” The brine ends up in ponds and the salt can be extracted as a saleable by-product.
Read the rest of this article here.
And now wind power can produce water too, it seems. We’re not talking about the wind farms built to power the giant, expensive and energy-hungry desalination plant at Wonthaggi. Here is Gizmodo Australia reporting on Eole Water’s new “dual action” turbine that generates energy, while extracting water from the air:
The WMS1000 Wind Turbine was invented by Marc Parent and is built by the French start-up Eole Water. Sitting atop a 24m mast, the machine generates electricity with a conventional 30kW direct-drive turbine in a 11-tonne nacelle with a 13m blade diameter. The WMS1000 can self-regulate the energy it produces, allowing it to provide a steady stream of power even in gusty or choppy winds. Installing an array of the turbines, which each have a service life of 30 years, creates a small-scale, decentralised power grid perfect for remote areas.
A lot of new wind turbines emerge with fresh technical breakthroughs. But the WMS1000 does something that no other wind turbine does — it generates fresh water. Lots of it. The WMS1000 sucks moisture right out of the air that’s spinning its blades. The turbine functions as a 1m wide, 5m long A/C condenser with an equally large heat exchanger. After the wind passes the blades, it flows through an intake in the body of the turbine, through a compressor, and then into the condenser. The water flows down a pipe in the centre of the mast while hot dry air exits the rear of the turbine.
The WMS1000 has been undergoing field testing in Abu Dhabi, where it has produced 500-800 litres of WHO-compliant water daily since being installed in October of last year. And that’s with humidity levels below 20 per cent and a respectable 50 per cent collection efficiency. Eole figures it can increase water production to 1000 litres a day if the technology is scaled up to a 25m diameter blade path, equivalent to some off-shore turbine models.
Read the rest of this article here.