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Robot glider harvests ocean heat

Sun, 10 Feb 2008 09:03:56 GMT

clipped by: abailart

A sea-going robotic glider that harvests heat energy from the ocean has been tested by US scientists.

The yellow, torpedo-shaped machine has been combing the depths of seas around the Caribbean since December 2007.

It generates its energy for propulsion from the differences in temperature between warm surface waters and colder, deeper layers of the ocean.

Wax-filled tubes inside the craft expand when it is gliding through warmer water. This heat is used to push oil from a bladder inside the hull to one outside, changing its buoyancy.

Cooling of the wax at depth reverses the cycle.

"Gliders can be put to work on tasks that humans wouldn't want to do or cannot do because of time and cost concerns," said Dr Fratantoni. "They can work around the clock in all weather conditions."

The team which developed the autonomous vehicle say it has covered "thousands of kilometres" during the tests.

Tags: energy harvesting

Generating Electricity with Your Knees

Fri, 08 Feb 2008 08:56:12 GMT

clipped by: abailart
clipper's remarks: I think 'energy harvesting' on a micro scale is an important contribution to macro energy issues.

Clip Source: news.bbc.co.uk

A stroll around the park may soon be enough to charge the raft of batteries needed in today's power-hungry gadgets.

US and Canadian scientists have built a novel device that effortlessly harvests energy from human movements.

The adapted knee brace, outlined in the journal Science, can generate enough energy to power a mobile phone for 30 minutes from one minute of walking.

The new device generates power by a process known as "generative braking", analogous to the braking systems found in hybrid-electric cars such as the Toyota Prius.

"Walking is a lot like stop-and-go driving," explained Dr Max Donelan of Simon Fraser University in Burnaby, Canada, lead author of the paper.

The knee brace is the latest development in a field known as "energy harvesting".

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The field seeks to develop devices and mechanisms to recover otherwise-wasted energy and convert it into useful electrical energy.

Tags: energy harvesting

UK Homes to be Totally Powered by Wind Farms

Sun, 09 Dec 2007 09:20:30 GMT

clipped by: abailart
clipper's remarks: People complain they are ugly, but I find windfarms somewhat beautiful....

Clip Source: environment.independent.co.uk

Britain is to embark on a wind power revolution that will produce enough electricity to power every home in the country, ministers will reveal tomorrow.

The Independent on Sunday has learnt that, in an astonishing U-turn, the Secretary of State for Business, John Hutton, will announce that he is opening up the seas around Britain to wind farms in the biggest ever renewable energy initiative. Only weeks ago he was resisting a major expansion of renewable sources, on the grounds that it would interfere with plans to build new nuclear power stations.

The revelation rounds off an unprecedented week in the battle against global warming in Britain and the United States. On Wednesday and Thursday measures to boost US use of renewable energy for electricity and motor fuel and cut greenhouse gas emissions were approved in Congress. The move comes as 190 nations meet in Bali, Indonesia, to negotiate what is seen as the world's "last chance" of avoiding the worst effects of climate change.

Tags: wind energy, climate change

Rise of the Humble LED

Fri, 07 Dec 2007 17:30:49 GMT

clipped by: abailart
clipper's remarks: Blue christmas trees everywhere this year!

Clip Source: news.bbc.co.uk

They wink at us every day from computer screens and stereos. But the humble LED is heading for a brighter future.

New generation Light Emitting Diodes will purify water, make lights that mimic the colour of sunshine, and keep private data immune from hackers.

"LEDs have enormous benefits over standard light bulbs because they're a great deal more efficient, come in a range of different colours and have a very long lifetime. They are also good at saving energy too,"

The colour of this light, and thus the LED, depends on the material that is used. Gallium arsenide gives off red light, while gallium nitride produced blue.

"Blue LEDs were the holy grail for a long time,"

"It's especially exciting from a third world perspective because LEDs could run off solar power or even by some sort of clockwork mechanism. This would bring water purification to people in remote areas,"

LEDs are currently expanding into the realms of computer security through a method known as quantum cryptography.

Tags: led technology