Clippings

Using Wind to Extract Fresh Water

"Researchers at Texas Tech are teaming up with General Electric (GE) to try to optimize what is in theory an ideal marriage: using wind turbines to power water-desalination plants. That way, many water-deprived areas could ultimately obtain clean drinking water in a sustainable way. And wind-turbine farms could gain a place to use excess electricity on high-wind days.

It may sound straightforward, but it's a tricky task: the water-desalination process envisioned for the project--known as reverse osmosis--operates best at stable, continuous rates. And that's difficult to achieve when the electricity source is variable. The technology goal is a control unit that can keep the desalination plant running as stably as possible, store some power at certain times, sell some to the grid at peak times, and also pump water to and from the system as necessary."

I suspect that the water towers are used to store energy during low wind conditions. The approach takes a 'systems view', combining elements with diverse inputs/outputs in a synergistic fashion. One might argue that each element has significant problems that incombination are turned into benefits.

Pocket Projectors

"As the lasers flash on the mirror, the mirror gimbals on its two axes, flickering to produce 30 million pixels a second, each illuminating a surface for 20 nanoseconds. Using this laser and single-mirror setup, the projector paints a scene onto a surface one pixel at a time, says Sprague. It does this so quickly that our eyes perceive a static image or a continuous movie.

One of the challenges is to design a rapidly gyrating mirror that can coordinate with the lasers that turn on and off 100 million times a second. "This mirror is thrashing all around, and the lasers are buzzing like crazy," says Sprague, "so you have to synchronize."

Integrated into the Microvision mirror, he says, are silicon mechanical structures that measure strain on the mirror, detecting what position it's in. This information is fed back into the laser modulator--the device that determines when a laser is emitting light or not--and the feedback loop allows the system to constantly adjust, depending on the demands of the projected image.

The mirror, its mount, and the other mechanical components are all made of silicon, putting the projector in a class of device called MEMS (microelectromechanical systems). Sprague says that Microvision developed most of the technology a couple of years ago, but it was waiting for one particular component to become available: a green laser that modulates at the rate required for the projector to work. Only recently have such compact, high-powered lasers become commercially available, he says (see "Ultra-Colorful TV")."

An example of adaptation, structured materials, miniaturization, integration...

How Plug-In Hybrids Will Save the Grid

The article talks about how plug-in hybrids could be charged at off-peak periods, improving the efficiency of the electrical system by soaking-up unused base load capacity, providing electricity buffers (grid operators currently must carefully balance supply and demand), and eventually contributing to an 'intelligent grid'.

The Open-Source Solution

The article describes the development and debugging of open-source software. Reliability tends to be excellent because of the number of eyeballs inspecting the code, in almost a competitive atmosphere of finding the first bug/writing the first fix. Usability can be a problem due to ad hoc addition of function creating complex code that does not follow a well defined architecture.

What prevents similar 'creeping excess' from weighing down natural systems? Is the key difference a tighter feedback loop? I suspect open-source developers are motivated by personal needs of accomplishment - feedback may be important but not sufficiently so.

citiesPLUS Catalyst Strategies

Canada submitted the citiesPLUS proposal for sustainable development of the Greater Vancouver area, as part of the International Gas Union Sustainable Urban Systems Design competition. The strategies are:

1. Protect and connect ribbons of blue and webs of green
2. Design multi-use spaces and convertible structures
3. Plan short loops and integrated infrastructure networks
4. Become net contributors
5. Experiment and learn as we go
6. Enhance the diversity of choices
7. Create shock resilient cells
8. Green and clean the import/export chains

Many of the strategies relate to the principles or preliminary list of patterns. Unfortunately, most of the strategies and examples seemed to lack depth, neither providing insight into how the strategy creates significant benefits nor how the strategy can be implemented. Again, here is an example where patterns (and Pattern Language) could provide significant value.

Robot propelled by heat energy from ocean

Robotic underwater 'gliders' obtain forward motion as they sink, then by increasing buoyancy, rise to repeat the process. Traditionally, these gliders have used motors and pumps to control buoyancy (see also Underwater Gliders for Ocean Research). A design by Doug Webb (Webb Research Corp) and the Woods Hole Oceanographic Institution are tapping into ocean temperature gradients to provide variable buoyancy. "Warmer water closer to the surface warms wax-filled tubes inside the engine, which expand to push oil from the interior to the exterior of the glider. As the glider dives and reaches deeper, colder waters, the wax cools and contracts, bringing the oil back to the interior."

Although horizontal speed is a leisurely one kilometer per hour, the propulsion system requires no batteries. A "thermal glider" launched in December has traveled 1,400 kilometers, making over 20 crossings of the 4,000-meter Virgin Islands Basin. Battery power is still required for sensors and control systems, although researchers are looking into ways of drawing this energy from the oceans.

Salt could shake up world energy supply

"Reuters, 19 March 2008 - Only up to powering light bulbs so far, "salt power" is a tantalising if distant prospect as high oil prices make alternative energy sources look more economical. Two tiny projects to mix sea and river water -- one by the fjord south of Oslo, the other at a Dutch seaside lake -- are due on stream this year and may point to a new source of clean energy in estuaries from the Mississippi to the Yangtze."

The Norwegian system uses osmotic pressure directly ("the power exerted by salt water sucking in fresh water is equivalent to water falling 270 metres in a waterfall"), while the Dutch system "captures salt particles which give off electrical currents." The systems produce 2-3 watts/metre of membrane, and need to reach 5 watts/metre to be commercially viable. A full-scale plant may need to have 100 acres (40 hectares) of membranes, which are currently quite expensive.