Sustainable Practices and Technology Photo Album

cow carved into Germany's countryside

2009-09-07T08:36:57Z

An aerial view shows a labyrinth in the form of a cow that is cut into a corn and hemp field in Marienfelde outside Berlin September 2, 2009. The labyrinth was created by the Federal Institute of Risk Assessment to raise awareness for healthy eating and dangers from harmful substances in food as well as to explain the digestion process in the stomach of a cow. REUTERS/Thomas Peter (GERMANY ENVIRONMENT SOCIETY IMAGES OF THE DAY)

turbine

2009-07-19T16:10:13Z

VW concept

2009-04-01T14:50:48Z

human footprint

2009-02-15T21:12:17Z

http://news.bbc.co.uk/2/hi/in_depth/629/629/7056601.stm http://quantumphysics.tribe.net/thread/abff270d-1c3e-4b13-b46c-9c7ac0a8195a#c8a53057-1267-4fec-88ce-4b379fc17419

Google Global Intelligent Utility Network

2009-02-11T20:39:42Z

http://www.eci.ox.ac.uk/research/energy/electric-metering.php

Solar

2009-01-22T16:54:47Z

laminar flow and turbulence in vapor

2008-08-03T05:09:12Z

glass dyes in solar concentrators

2008-07-14T16:43:14Z

VAWT mechanicals

2008-07-10T06:33:21Z

for each clockwise rotation of the unit, each foil rotates 1/2 turn counter clockwise

another unique VAWT design

2008-07-10T06:29:41Z

There are at least two other people who have played with this design. John Boothman and a kirsten boeing design

turbocharger

2008-05-28T11:43:54Z

improved power to weight ratios

Savonius VAWT

2008-05-24T22:52:47Z

Savonius turbines are used whenever cost or reliability is much more important than efficiency. For example, most anemometers are Savonius turbines, because efficiency is completely irrelevant for that application. Much larger Savonius turbines have been used to generate electric power on deep-water buoys, which need small amounts of power and get very little maintenance. Design is simplified because, unlike horizontal-axis turbines, no pointing mechanism is required to allow for shifting wind direction and the turbine is self-starting. Savonius and other vertical-axis machines are not usually connected to electric power grids. They can sometimes have long helical scoops, to give smooth torque. -Wikipedia

Horizontal Axis Wind Turbine

2008-05-24T07:59:57Z

When you picture a windmill, chances are you picture a horizontal axis windmill. There are several advantages to a HAWT. One of these is that it’s more stable than a VAWT because the blades are to the side of the turbine’s center of gravity. On a VAWT, the blades spin around the center of gravity, which decreases stability. Also, HAWTs are generally taller than VAWTs. The height of a HAWT ranges from 200 to 300 feet, while VAWTs are generally half that. HAWTs are also usually self-starting, so they don’t require a motor to start the rotation. HAWTs are also generally cheaper, mainly due to high production. However, the biggest advantage to a HAWT wind turbine is that the angle of the blades can be changed. This is helpful both in maximizing efficiency by catching the wind, but also in minimizing damage during a storm. There are disadvantages to HAWTs, though. For example, transportation can cost up to 20% of the total price due to difficulty transporting the tower and blades (which can be up to 180 feet long!) These tall towers are also difficult to install, requiring enormous cranes and specialists. Also, there are major concerns about tall towers interfering with radars at air force bases and with bird migration cycles.

Vertical axis wind turbine

2008-05-24T07:52:04Z

The alternative to horizontal axis wind turbines are vertical axis wind turbines, or VAWTs. These are rather odd-looking structures that resemble egg beaters. The advantages of VAWTs are that they are easier to maintain and repair because most of the moving parts are near the ground. In some places such as mountains, mesas, and other high places can have winds closer to the ground in which a VAWT can produce more energy than a HAWT, which would be placed higher up. Also, the low height can be useful in avoiding conflict with local ordinances. VAWTs can also be easier and thus less expensive to transport and install because of the low height. They do, however, have many disadvantages. One major one is that most VAWTs produce only 50% as much energy as HAWTs. This is because of extra drag that is created when the blade faces into the wind. Also, most VAWTs must be installed on flat ground, and can’t handle steeper slopes that HAWTs could. Another disadvantage is many VAWTs require energy to start because the starting torque is so low that there is usually not enough wind power to start the turbine.

Smokey Bear & The Campers

2008-05-18T22:28:00Z

replacing filament with leds

2008-05-15T15:37:27Z

solar walkway led motion dimmer

2008-05-06T19:45:04Z

this is progress on a project on my electronics bench. the 8 leds (salvaged from solar powered walkway lights) are dimmed in and out with optoisolator electronics triggered by a motion detector. there is more work to do to finish, but the dimmer and power output section work fine here.

solar thermal

2008-05-04T03:32:42Z

beach

2008-04-11T19:49:40Z

1.2MW turbine

2008-04-10T03:31:34Z

http://www.enn.com/energy/article/34319

Spring Green

2008-03-26T22:47:17Z

MIT Solar 7

2007-09-15T18:46:58Z

MIT's entry to the 2007 International Solar Decathalon

drawing of a living barn

2007-01-29T20:40:28Z

Sun EZ-1 SX Recumbent Bike

2006-09-19T15:47:52Z

The Comfortable Solution when there is No More Oil!

EcoVillage at Ithaca NY

2006-05-09T23:57:17Z

This is the original neighborhood in the EcoVillage. A second one has been built, and a third is being planned.