Friday, December 29, 2006

Star Rotor Engine

source: http://sustainabledesignupdate.com/?p=71

It seems every few months I read about another newer and better internal combustion engine in development. Having reviewed dozens of engines, all purporting to save energy and lower emissions, I find very few have a real chance of ever getting off of the drafting board and into our cars. Not so with the Star Rotor. This engine, in development at Texas A&M, has a real chance of getting to market. Testing is ongoing on the compressor section, which shows an 82% efficiency, and soon the expander will be similarly tested.

The Star Rotor is another invention from Dr. Mark Holtzapple whom I have previously posted for his work on developing biofuels.

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Wednesday, December 13, 2006

Beyond Ethanol

source: http://sustainabledesignupdate.com/?p=66


There is more than one way to get liquid fuel from bio-mass. We have covered cellulosic ethanol in an earlier SDU posting (here). Now we look at making a mix of various alcohols from almost any cellulosic material, including municipal solid waste and sewage sludge. By using these waste streams as the fuel feed stock, the MixAlco process can provide a large fraction of our fuel needs without displacing valuable crop lands or using high energy crops such as corn.

The MixAlco process converts biomass from any source into organic chemicals and alcohols via lime pretreatment; non-sterile, acidogenic digestion; product concentration; thermal conversion and hydrogenation. Because they have low capital costs and relatively simple operation, the MixAlco pretreatment and fermentation steps may be carried out on-location at sewage treatment plants or municipal landfills. Several studies have shown that MixAlco is capable of economically converting dairy manure and chipped yard waste into carboxylic acids which can be converted to alcohol.

Professor Mark Holtzapple, holder of many patents on this process makes a great presentation at Texas A&M on the MixAlco process and his Star Rotor engine which is currently under development.

Check out Prof. Holtzapple’s presentation here.

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Tuesday, November 21, 2006

Save on Hot Water

source: http://sustainabledesignupdate.com/?p=61

GFX Heat Exchanger

We are working on an energy efficient renovation to an all electric house in Florida. In addition to using renewable energy we are looking at greatly reducing energy use. One of our energy saving strategies is to use a waste water heat exchanger. These devices efficiently pull heat out of waste water and put it into the water heater.

Excerpeted from Rocky Mountain Institute â€Å"Home Energy Briefs #5”

In the average home 80–90% of the energy used to heat water goes down the drain. A water based heat exchanger can capture a lot of the heat in drain-water and put it to use pre-heating the water going in to your hot water supply . One type, called a â€Å"gravity film exchange drain-water heat recovery system” has been found to save 25–30 percent of total water-heating energy. This technology is compatible with all types of water heating systems, but it is especially suitable with on-demand water heaters and solar thermal systems. Prices range from $300–400 and paybacks are in the range of 2.5 to 7 years, depending on how often it is used. For more information on this technology, visit www.gfxtechnology.com.

From the GFX Technology Website:

Perhaps the most important and immediate benefit to owners of all-electric homes is GFX’s power-boost; enough to triple the shower-capacity of tank-type water heaters and halve the cost of a shower. For example, if GFX boosts cold water temperatures by 30 degrees, it’s feeding back about 10 kW of power; more than enough to triple your family’s showering-time and save 2 kW of energy per 12-minute shower. This means if you pay 8.5 cents to 17 cents per kWh for electricity and your yellow water heater sticker shows an efficiency rating (energy factor) of 85%, GFX could save you 20 cents to 40 cents per shower, depending upon where you live and type of showerhead installed.

GFX gives an electric water heater the capacity of a gas heater. In fact, when tested with GFX, the first hour rating of two types of high efficiency 50-gallon electric water heaters tripled to 180 gallons; more than “double the capacity of typical 50-gallon gas heaters” â€" with an energy factor rivaling that of a heat-pump, plus unsurpassed reliability and quietness.

According to U.S. EPA standards, if just 6 million electric water heating systems were to be upgraded by GFX, carbon dioxide emissions would drop by more that 20 million tons per year; the amount released by burning 1.8 billion gallons of oil.

All-copper construction means GFX will last as long as your plumbing system and will pay for itself many times over. Safety is guaranteed by U.L.-approved, double- wall-vented construction and self-cleaning ensures maintenance-free operation at peak efficiency. The falling-film heat exchanger models listed in the table below have ultra-high heat transfer coefficients required for compact size and high capacity.

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Monday, November 6, 2006

Solar WiFi

source: http://sustainabledesignupdate.com/?p=57


I have long been an advocate for municipal WiFi systems.

Municipal WiFi systems are municipally sponsored network mesh WiFi internet systems that typically allow low cost and no cost access to broadband connections. As access to information becomes more important for all of us to keep up with developments in politics, culture, and technology it becomes even more important that we don’t leave some people behind.

A municipal government may not come to your mind first when you think about broadband services. Many people may prefer the free market, but municipal governments are in the business of providing roads, police and fire protection, water and sewage treatment. Why not access to information?

Access to information is the backbone of our democracy. Here are a few of the reasons Muni WiFi is a good idea -

Muni WiFi Allows:

1. Municipal and residential scale â€Å"smart metering” of energy use.

2. Traffic congestion monitoring to reduce energy wasting traffic snags.

3. Cost-effective connectivity for both traditional office, mobile and at home workers in Municipal government and business.

4. Untethered access to information which helps improve productivity by allowing City field personnel to work more effectively with office personnel.

5. Complimentary access for visitors and tourists to enjoy during their stays.

Treehugger has an interesting take on St. Louis Park in Minnesota where they propose to go WiFi on renewable energy:

First Solar Wifi City in the US?

St. Louis Park, an unassuming city a few miles west of Minneapolis, may be the first in the country to provide solar-powered wireless internet to its residents. If the idea passes a final City Council vote next week, they will begin the installation of a network of wifi nodes powered by some 400 PV panels situated on public infrastructure around the city. It’s not free however, and through the public/private partnership, residents would be able to pay $15 a month for 128 kilobyte speed or $20 for 1 meg (which does appear to be a pretty decent deal). As reported in the Star Tribune, the city expects to save $40,000 to $50,000 a year by using an entirely solar-powered system as opposed to grid power.

Green wireless internet is a spreading meme. The NGO Green Wifi is hoping to bring solar wireless to people in the developing world, a notion meant to dovetail with the $100 laptop. In NY, a group is selling pixels to raise the funds for a solar and wind powered system, while a handful of other cities (like San Francisco and Boulder) are wrangling with free-wireless-for-all legislation. Some are even working out back pack hacks, while others eschew wifi altogether. Folks in St. Louis Park will know on Nov. 6th whether their solar-powered wireless network is a green light. :: The Star Tribune via Hugg (Jetsongreen the incredible!)!

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Friday, October 27, 2006

BioDiesel

source: http://sustainabledesignupdate.com/?p=56

BioDiesel Pump

Support Midwest Farmers or Middle East Oil Barons?

Biodiesel is a clean burning alternative fuel made primarily from vegetable oil. Biodiesel is a renewable resource, it contains no petroleum and it can be blended with regular diesel fuel to create a biodiesel blend. It can be substituted for diesel fuel in diesel engines with no modification. Biodiesel is biodegradable, nontoxic, and very low polluting when compared with standard diesel. I have tried both 20% and 99% blends of Biodiesel and I find that my diesel car runs perfectly on these fuels plus it doesn’t have the characteristic diesel smell.

Biodiesel is made through using acids to separate glycerin from vegetable oil or fat. The process leaves behind two products â€" methyl esters (the chemical name for biodiesel) and glycerin (a valuable byproduct usually sold to be used in soaps and other products).

Biodiesel is good for the environment because it is made from renewable resources and has lower emissions when compared to petroleum diesel. It is less toxic than table salt and biodegrades as fast as sugar. Since it is made in the USA from renewable resources such as soybeans, its use decreases our dependence on foreign oil and contributes to our own economy. Support Midwest farmers or middle east oil barons?

Biodiesel is available nationwide. It can be purchased directly from biodiesel producers and marketers, petroleum distributors, or at a handful of public pumps throughout the nation.

More information at the National BioDiesel Board: http://www.biodiesel.org/

An interesting article on “The Conscientious Cruiser” a BioDiesel bus converted to a sustainable design classroom by SDU friend Amy Grettum: Link Here

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Wednesday, October 18, 2006

Peak Aluminum

source: http://sustainabledesignupdate.com/?p=54

If you have been reading this column for any length of time you have heard of “Peak Oil”. Simply put we reach the point of Peak Oil when the peak of oil production occurs. There is some debate on when we will reach the peak of oil production, but no debate on if we are going to reach a peak in production. There is much debate on the effects associated with Peak Oil production but most economists predict some pretty rough times ahead.

Well… We are also going to reach peak production in a number of other materials we mine from the earth’s crust. Right now we have less than half of all known aluminum ore (bauxite) remaining, as well as copper, lead, tin and iron.

The floks over at Transtudio have a post on the peak supply of these important building materials.

Raw Material Time Horizons

Based on a recent United States Geological Study, Lester Brown informs us that we will exhaust known stores of several vital metals within the next two to three generations, based on a reasonable estimation of 2% growth in extraction.1 While recycling efforts have accelerated, virgin materials are still being harvested at an alarming rate.

What will the world be like when we have run out of copper or steel? The average building today relies upon a great quantity of these resources for its construction. Faced with these facts, we can easily imagine a future in which industry has completely re-engineered its handling of material resources. After all, there seems to be no other choice.

1Brown, Lester, Plan B 2.0, New York: W. W. Norton, 2006. p. 109

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Thursday, September 21, 2006

Recycled Blue Jean Insulation

source: http://sustainabledesignupdate.com/?p=49

Recycled Blue Jean Insulation (by Bonded Logic)

My presentations about environmentally preferable construction practices include a lot of hands on examples of the latest in green construction materials. One sample that always draws a crowd is my old tattered sample of recycled blue jean insulation. I think people are drawn to it because it feels soft and comfortable and it is easy to tell where it comes from.

The insulation is called “UltraTouch” and Bonded Logic Inc. is the manufacturer, here is a bit from their website:

UltraTouch Natural Cotton Fiber insulation is the successful combination of
25 years of insulation experience and a revolutionary patented manufacturing process that has created a superior and safe product.

UltraTouch is made from high quality natural fibers. These fibers contain inherent qualities that provide for extremely effective sound absorption and maximum thermal performance. UltraTouch DOES NOT ITCH and is very
easy to handle and work with.

UltraTouch contains no chemical irritants and requires no warning labels compared to other traditional products. There are no VOC concerns when using UltraTouch, as it is safe for you and the environment.

UltraTouch is also a Class-A Building Product and meets the highest ASTM testing standards for fire and smoke ratings, fungi resistance and corrosiveness.

UltraTouch contains 85% post-industrial recycled natural fibers making it an ideal choice for anyone looking to use a high quality sustainable building material.

By installing UltraTouch, you are making both your building and the environment a safer place to live, work, and enjoy.

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Thursday, September 14, 2006

Photo in the news: Arctic ice melting rapidly, study shows

source: http://news.nationalgeographic.com/news/2006/09/060914-arctic-ice.html

The rate of ice loss in the Arctic is accelerating rapidly, scientists say.

According to data from NASA's QuikSCAT satellite, between 2004 and 2005 the Arctic lost an unprecedented 14 percent of its perennial sea ice (shown in white)�some 280,000 square miles (725,000 square kilometers), or an area the size of Texas.

Perennial ice remains year-round and has a thickness of ten feet (three meters) or more. That ice was replaced with seasonal ice 1 to 7 feet (0.3 to 2.1 meters) thick (shown in pink), which is much more vulnerable to melting in the summer.

Since the 1970s summer ice in the Arctic has reduced at a rate of 6.4 to 7.8 percent per decade, the researchers write in the September 7 issue of the journal Geophysical Research Letters. This suggests ice loss may now be occurring up to 18 times more quickly.

(Related: "Arctic Ice Levels at Record Low, May Keep Melting, Study Warns" [October 2005].)

Ice wasn't lost from all areas equally. The east Arctic Ocean lost 50 percent of its perennial ice. Much of the ice was pushed by winds and other factors into the western part of the ocean, where the perennial ice sheet actually grew.

But global warming probably played a significant role as well, and additional ice loss could trigger a feedback loop that would further accelerate the melting process, scientists say.

"If the seasonal ice in the east Arctic Ocean were to be removed by summer melt, a vast ice-free area would open up," research leader Son Nghiem of NASA's Jet Propulsion Laboratory in Pasadena, California, said in a press statement. "Such an ice-free area would have profound impacts on the environment, as well as on marine transportation and commerce."

The scientists report that the eastern Arctic's perennial ice sheet was reduced a further 70 percent between October 2005 and April 2006.

-- Aalok Mehta

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Wednesday, August 30, 2006

Hydrogen Airplane

source: http://sustainabledesignupdate.com/?p=40

Diamond DA-36

Modified Diamond Airplane To Run On Hydrogen Fuel Cell

Air travel contributes significantly (about 3.5 percent) to global CO2 emissions, aircraft designers at Boeing have announced plans to develop an all-new, emission-free, hydrogen-powered plane.

Boeing Research and Technology in Madrid, Spain is the lead company working on developing a hydrogen powered airplane.

Diamond Aircraft of Austria is supplying the demonstrator airplane, based on a certified Katana Xtreme motor-glider and Intelligent Energy of the United Kingdom is providing a Proton Exchange Membrane fuel cell for a demonstration prototype hydrogen powered airplane.

Boeing Research and Technology in Madrid, Spain is the lead company working on developing a hydrogen powered airplane.

Check out Sunday Times reports, and Green Car Congress

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Tuesday, August 29, 2006

Spherical Solar Cells

source: http://sustainabledesignupdate.com/?p=39

Spherical Solar Cells

Micro Spherical Solar Cells

Sphelar® spherical solar cells are a new product developed by Kyosemi Corporation. Unlike conventional flat solar cells, Sphelar® are small and spherical in shape. Kyosemi believes the spherical shape makes their cells capable of power generation with greater efficiency than traditional crystaline solar cells.‚ Sphelar products are made up of tiny solar cell spheres measuring a mere 1 mm across in a transparent flexible membrane.

Link - Kyosemi PDF

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Monday, August 14, 2006

Terra Preta: Black is the New Green

source: http://www.worldchanging.com/archives//004815.html

By David Zaks and Chad Monfreda

Carbon sequestration faces some major hurdles. Technical geosequestration methods could pump large amounts of CO2 deep underground but are still under development. On the other hand, natural methods that store carbon in living ecosystems may be possible in the short term but require huge swathes of land and are only as stable the ecosystems themselves. An ideal solution, however, would combine the quick fix of biological methods with the absolute potential of technical ones. Terra preta may do just that, as a recent article in the journal Nature reveals.

Amazonian Dark Earth, or terra preta do indio, has mystified science for the last hundred years. Three times richer in nitrogen and phosphorous, and twenty times the carbon of normal soils, terra preta is the legacy of ancient Amazonians who predate Western civilization. Scientists who long debated the capacity of 'savages' to transform the virgin rainforest now agree that indigenous people transformed large regions of the Amazon into amazingly fertile black earth. The Amazonians' techniques remain an enigma but are believed to have used slash-and-smolder to lock half of the carbon in burnt vegetation into a stable form of biochar instead of releasing the bulk of it into the atmosphere like typical slash-and-burn practices.

The difference between terra preta and ordinary soils is immense. A hectare of meter-deep terra preta can contain 250 tonnes of carbon, as opposed to 100 tonnes in unimproved soils from similar parent material, according to Bruno Glaser, of the University of Bayreuth, Germany. To understand what this means, the difference in the carbon between these soils matches all of the vegetation on top of them. Furthermore, there is no clear limit to just how much biochar can be added to the soil.

Claims for biochar's capacity to capture carbon sound almost audacious. Johannes Lehmann, soil scientist and author of Amazonian Dark Earths: Origin, Properties, Management, believes that a strategy combining biochar with biofuels could ultimately offset 9.5 billion tons of carbon per year-an amount equal to the total current fossil fuel emissions!

Indeed, there is profit to be made in this black earth, for if green is the new black, then black could be the new green. Biofuels are touted as 'carbon neutral', but biofuels and biochar together promise to be 'carbon negative'. Danny Day, the founder of a company called Eprida is already putting these concepts into motion with systems that turn farm waste into hydrogen, biofuel, and biochar.

The Eprida technology uses agricultural waste biomass to produce hydrogen-rich bio-fuels and a new restorative high-carbon fertilizer (ECOSS) ...In tropical or depleted soils ECOSS fertilizer sustainably improves soil fertility, water holding and plant yield far beyond what is possible with nitrogen fertilizers alone. The hydrogen produced from biomass can be used to make ethanol, or a Fischer-Troupsch gas-to-liquids diesel (BTL diesel), as well as the ammonia used to enrich the carbon to make ECOSS fertilizer.
We don't maximize for hydrogen; we don't maximize for biodisel; we don't maximize for char...By being a little bit inefficient in each, we approximate nature and get a completely efficient cycle.

Terra preta's full beauty appears in this closed loop. Unlike traditional sequestration rates that follow diminishing marginal returns-aquifers fill up, forests mature-practices based on terra preta see increasing returns. Terra preta doubles or even triples crop yields. More growth means more terra preta, begetting a virtuous cycle. While a global rollout of terra preta is still a ways away, it heralds yet another transformation of waste into resources.

How ironic it is that ancient humans cultivated the very fertility of Earth's most pristine places so seamlessly as to be nearly invisible. Perhaps then our challenge as planetary gardeners is not to preserve nature in a bubble but to reweave ourselves into it-to invert our footprints into handprints.

(Thanks, Garry!)

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Wednesday, July 26, 2006

Super Efficient Lighting

source: http://sustainabledesignupdate.com/?p=31

LED Throwies - www.instructables.com

L.E.D. Lights - Photo www.instructables.com

I am a big fan of LED lighting. LEDs are simply solid state lighting on a chip. The potential efficiency for LEDs is very high and the color quality is potentially unlimited. Current LED technology is such that a single LED makes light at one wavelength. Red LEDs are commonly used in such applications as traffic signals and automobile tail lights. As the technology has developed more colors have been introduced to the market. A recent development is the white LED. White LEDs are made up of a blue LED plus special coatings that convert blue light to other colors in the spectrum. The final quality of the light is dependent on the quality of the phosphors. A second way to make white light is to have a variety of color LEDs that blend together to make white light.

Recently the efficiency of LEDs has greatly surpassed other forms of electric light. An article in EETimes:

L.E.D. Lights - Photo www.instructables.com

I am a big fan of LED lighting. LEDs are simply solid state lighting on a chip. The potential efficiency for LEDs is very high and the color quality is potentially unlimited. Current LED technology is such that a single LED makes light at one wavelength. Red LEDs are becomming common in such applications as traffic signals and automobile tail lights. As the technology has developed more colors have been introduced to the market. A recent development is the white LED. White LEDs are made up of a blue LED plus special coatings that convert blue light to other colors in the spectrum. The final quality of the light is dependent on the quality of the phosphors.

A second way to make white light is to have a variety of color LEDs that blend together to make white light.

Recently the efficiency of LEDs has greatly surpassed other forms of electric light. An article in EETimes:

Cree white LED produces 131 lumens per watt

Spencer Chin

EE Times

(06/20/2006 5:28 PM EDT)

MANHASSET, N.Y. — Cree Inc. said it has produced a white LED with efficiency of 131 lumens per watt, confirmed by the National Institute of Standards and Technology.

“This is the highest level of efficacy that has been publicly reported for a white LED and raises the bar for the LED industry,” said Scott Schwab, Cree general manager, LED chips, in a statement.

Semiconductor suppliers have racing to produce higher efficiency white LEDs as the industry seeks energy-efficient alternatives to conventional lighting. In March, Japan-based Nichia Corp. reported it had developed a white LED rated 100 lumens per watt.

Last September, Cree (Durham, N.C.) said its white XLamp 7090 Power LED was capable of producing 86 lumens per watt.

Lumens-per-watt is the standard used by the lighting industry to measure the conversion of electrical energy to light. As a reference, conventional incandescent light bulbs are typically in the 10 to 20 lumens per watt range, while compact fluorescent lamps range from 50 to 60 lumens per watt.

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Tuesday, July 18, 2006

Water Efficiency

source: http://sustainabledesignupdate.com/?p=30

Arenal Waterfall

We (I mean Archiopolis Architects when I write we) feel water conservation and our care for the environment is reflected in how we design with water. We believe that water should flow, gurgle and percolate into the ground on our projects in about the same manner it did before we started work. This means we pay careful attention to surface drainage, runoff, soil types and prevailing winds. Sometimes a site will recommend that we design specific water features while other times we help water flow into the aquifer.

Inhabitat has a continuing series on Sustainable Design, recently they covered Water Efficiency.

Inhabitat:

There are few things we take for granted as much as our ability to turn on the tap and get water in seemingless endless supply. Even during droughts, and in spite of ubiquitous advertising about shortages and conservation, most of us treat this precious resource as a given.

The average American uses 80-100 gallons of water per day; and while less than half of it will be drunk or used to cook food, chances are that all of it is treated, potable water from the municipal water provider. What many people don‚'t realize is that it's fairly easy to implement simple systems for recycling and reusing water on your own property, drastically decreasing the demands on shared supplies, and in turn, reducing your water bills.

Read on for details on the three LEED-H criteria for water efficiency at home, plus some additional information on innovations in wastewater treatment and reuse.

Green Building 101, water efficiency, efficiency, water, rainwater catchment, collection, cistern
Glen Murcutt's South Wales house collects and funnels water through the roof's central groove.

1) Water Collection and Reuse: If you hate to miss out on a great bargain, look out the window next time it storms to see what you're passing up there's no more cost effective water source than rain. In fact, if one rainstorm drops 1 inch of rain on your yard, you have just watched the equivalent of over 250 bathtubs full of water trickle by!

The first step for increasing water efficiency at home is to reduce the use of drinkable water for non-consumption purposes. There are two ways to do this: collect rainwater and reuse indoor wash water. You can install cisterns above or below ground that will collect and store run-off from rooftops and other impervious surfaces; as well as from laundry machines, dishwashers, bathtubs and sinks (this is classified as grey water, meaning that it does not include human waste or sewage).

These collection tanks can then serve as an on-site supply for watering your lawn and garden. It's also possible to reuse grey water indoors in toilets and for washing, but the regulations and requirements are a bit more complex than for outdoor use. Regardless, there are varying degrees of treatment and filtration that can be installed in conjunction with your cistern, depending on what you intend to use the water for.

Green Building 101, water efficiency, rainwater, cistern, collection, water, efficiency, catchment, reuse
Stay tuned for more on this gem of a site-sensitive house in the next week.

2) Irrigation: How many times have you driven past someone's house during a midsummer downpour and seen their sprinkler system going full blast in spite of the free water falling from the sky? The irrigation of lawns and gardens consumes up to 50% of the potable water we bring onto our property.

This is an instance where technology can be hugely beneficial in conserving natural resources. You can install smart, programmable sprinkler systems and moisture sensors that allow you to measure the amount of water your yard needs at any given time, and control irrigation from a central shut-off valve. Combine this system with your rain and waste water collection and you've got your outdoor greenery dialed.

As was pointed out in last week's Green Building 101 installment on Sustainable Sites, its wise to choose landscaping elements that are appropriate to the climate and require minimal water. Because of their varying root systems, grass, trees, and flowers all have different water requirements. When you design your garden, consider the layout of the irrigation system, and try to arrange plants according to the amount of water they need.

Green Building 101, water efficiency, landscape, garden, water, irrigation, reuse, grey water
Researching water-wise plants for your particular region makes a lower-maintenance, lower-cost garden.

3) Indoor Water Use: The primary means of reducing indoor water use has to do with the fixtures you choose. Selecting low-flow sink and bathtub faucets, showerheads and toilets can reduce indoor water use by 30-40%. Over the last few years, the quality of low-flow fixtures has increased. Whereas at first they gained a reputation for flushing inefficiently or delivering unsatisfactory water pressure, new products are surpassing the original designs. The other great way to ensure that you are getting maximum water efficiency indoors is to purchase Energy Star appliances, which guarantee a certain degree of water efficiency, and save energy to boot.

water, efficiency, Green Building 101, home, bath, environment
The Kohler Watertile is designed to be water efficient (if you don't install 6 of them in one shower!)

Water Treatment Using Nature Tools
Because water is so vital, and because the ability to clean and reuse it becomes increasingly important, it's an area where we've seen significant evolution and real innovation over the years. Early building strategies recognized the value on a single slant roof, which allows run-off to be collected in one place. Likewise, gravity obviously supports water pressure, so the higher above ground a storage tank sits, the more efficiently the water will feed out.

Green Building 101, water efficiency, Living Machine, Eco Machine, John Todd, water, wastewater treatment, bioremediation, efficiency

Then there is the natural water-filtering ability of plants a form of bioremediation which a number of ecologists, scientists and engineers have learned to harness for large scale filtration of contaminated water. Ecologist John Todd's Living Machines (now known as Eco Machines) create consolidated ecosystems which treat wastewater and sewage using aquatic plants, fungi, and other organisms. These have generally been used in commercial-scale operations, and not scaled down for residential purposes, or up for city-wide water treatment. But the concept reminds us that our own greenspace can be a filter for the water we waste, making reuse easier.

If you're a regular reader, you know we take every opportunity to promote green roofs which are a great way to utilize rain water and divert it from running off-site. Other rain catchment systems can be devised in the form of botanical facades, and modular permeable pavement. Whatever you can do to make use of rain and wastewater means you spare your city sewers from an overflow of contaminated water, and you end up with a more fertile, verdant garden.

water, home, green building 101, floating, efficiency
You can’t get much more aware of the water than in a floating home, like this one from the Dutch Waterstudio.

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Friday, July 14, 2006

Renewable Energy Boost

source: http://sustainabledesignupdate.com/?p=28

Wind Farm - Photo by National Renewable Energy Lab

For a long time renewable energy technologies have needed a financial “shot in the arm” for research and development. This need is particularly strong in the area of design for manufacturability. It now looks like China will make the needed infusion of cash that will make renewables competitive in future markets. Unfortunately this will further reduce US competitiveness in renewable and clean technologies.

Reuters has an interesting article today.

HONG KONG (Reuters) - China is set to spend $200 billion on renewable energy over the next 15 years, and industry players are racing to grab a slice of the action.

That kind of money would buy you an oil firm the size of Chevron and leave change to fund the current renewables programs of all Europe’s top oil firms for 25 years.

So from the arid plains of Xinjiang to the rolling hills of sub-tropical Guangdong, Chinese and foreign firms are erecting 40-storey wind turbines, installing solar panels, and conducting tests on corn for biofuel.

Beijing wants a tenth of its energy to come from environmentally friendly sources by 2010 â€" a desire driven by soaring air pollution and chronic environmental degradation that is swelling medical bills and provoking discontent.

Projects will need turbines, blades and other power components, which is why General Electric Co., Vestas Wind Systems and Gamesa, as well as homegrown firms China Solar Energy Holdings Ltd. and Suntech, are expanding capacity in the country.

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Thursday, June 15, 2006

Sustainable Cities

source: http://sustainabledesignupdate.com/?p=25

We are increasingly becomming a species that lives in cities. The folks over at Treehugger.com have a nice review of the 2006 Sustainable Cities listing put together by SustainLane.

SustainaLane released its 2006 sustainability rankings of the US’ fifty largest cities, and the results show that a handful of American cities are positioning themselves as models of sustainable urban development. Portland, Oregon took top honors again, followed by San Francisco and Seattle â€" no surprises there. Completing the top ten list were: 4. Philadelphia 5. Chicago 6. Oakland, Calif. 7. New York 8. Boston 9. Denver 10. Minneapolis.

Once we got past the top three, we began to do a little head-scratching. Top 10 cities Philadelphia and New York made another top 10 list this year: the top 10 most polluted cities as ranked by the American Lung Association. In the next tier, we found that Albuquerque, Tuscon, Phoenix and Los Angeles all made the top 25, and Las Vegas was close behind at #27. Given all of these cities’ reputations for massive amounts of sprawl and water consumption, their placement seemed… well… interesting. Looking at SustainLane’s very thorough overview of its methodology gave us a better sense of how and why some cities fared as well as they did.

From the SustainLane website:

How does SustainLane define sustainability? The SustainLane US City Rankings focus on healthy regional economic development, vibrant communities and quality of life measurements. Our viewpoint of sustainable practices is weighted toward ideas borrowed from our natural systems and implemented in our cities, particularly those geared toward the revitalization of our economy and public health. SustainLane also wants to celebrate the inspirational leaders showing us the way to a better future.

Specifically, we take a look at some of the newer areas generating exciting economic growth opportunities, including the US Green Building Council’s LEED (Leadership in Environmental & Energy Design) building certification, the fastest growing construction category in the United States. There are several high-rise office building planned in New York City pursuing LEED’s highest (gold and platinum) standards, including the 2.1-million-square foot 56-story Bank of America Tower in Manhattan. With each such LEED project come new technologies, products and services, which benefit the local economy of that metropolitan area, displacing less sustainable industries. Unsustainable enterprises will soon become dinosaurs if they do not quickly learn to adopt more sustainable practices. LEED standards will soon be expanded to include community planning and the residential market, and SustainLane will be right there following these developments, providing measures of success, implementation stories and shared learning opportunities.

Another exciting trend is the national explosion of farmers markets, which according to the US Dept. of Agriculture grew at a clip of 106% from 1994 through 2004. Farmers markets generate $888 million in yearly revenue across the United States (USDA 2005 estimate), and work to bring the consumer in direct contact with those that grow their food. This trend quickens the movement to understanding the complex connections between our daily lifestyles and consumptive habits (the food we prepare and eat every day). As communities become more knowledgeable about sustainability issues, daily individual practices change, and this citizen engagement in turn helps cities move closer to becoming cleaner and more productive environments.

We think Mayor Gavin Newsom of San Francisco (#1 overall in our study) got it right when he told us. Sustainability is important not only for protecting citizens health and ensuring a great quality of life here in San Francisco, but also for boosting the local economy with jobs and services in everything from clean technologies to fresh food and green building products.

Sustainability concerns are driving the development of renewable energy for buildings and clean fuels for vehicles. In Berkeley, California, 200 city trucks burn 100% biodiesel fuel from used cooking oil. Meanwhile, other cities are examining and deploying alternative fuels from corn and agricultural byproducts in vehicle fleets numbering in the thousands, significantly cutting US dependence on increasingly costly fossil fuel sources and reducing local air pollution.

In addition to air and water quality, local food, LEED buildings, renewable energy/climate, and green fleets, SustainLane looked at waste diversion rates. These programs now include not only recycling but also highly innovative composting systems linking city restaurants with regional farmers and vineyards. And, we analyzed planning, zoning, and land use, which impact everything from the availability of recreation opportunities to how much people are dependent, or not dependent, on driving everywhere for everything.

Two final categories, city innovation and knowledgebase, examined how well cities are developing everything from new financial and behavioral incentives, to communications and information management processes and technologies.

It is interesting to note that Detroit ranked second to last in the 2005 survey and in the top 50 in the 2006 survey. While we (Archiopolis Architects) have designed over a dozen new renewable energy systems in the Detroit area over the last year, I don’t think just that would account for such a jump in the rankings.

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Monday, May 22, 2006

New Technology for Air Conditioning

source: http://sustainabledesignupdate.com/?p=22

Waterfall

Every few years I hear of a new technology that simply amazes me. One such technology is the refrigeration known as R718 or simple water vapor.

How does it work? Is it efficient? Why doesn’t everyone use it? I asked myself when I first heard of it.

It turns out R718 has been around for a long time. In Europe they have used it for years, primarily driven by their high energy prices. R718 can be more efficient than our current refrigerants (R134A for example), but it takes a special type of compressor to make it work. The compressors used in Europe have titanium turbines. The expensive titanium is used because they have to spin very fast to get the right pressures and in Europe where the energy costs are relatively high, it makes good economic sense. The titanium compressors are too expensive to use in the United States - it takes too long to recover the initial expense through energy savings. That is ’till now.

(Editor’s note: I am working on the development of a novel R718 air conditioner, I have submitted for some funding so what you read is not entirely impartial)

The Stratos Company LLC (of which I am president) is working with Prof. Norbert Muller of Michigan State University on the development of a novel R718 air conditioner that is very inexpensive. The key to success has been the development of a special turbine that is made in a very cleaver way such that you can substitute relatively cheap carbon fiber plastic for titanium! The text below is from a grant application.

Background
Air conditioning systems consume roughly 11% of the energy used in US buildings, and are the main contributors to peak demand in summer months leading to brown-outs and black-outs of the electric grid. What's more, air conditioning loads are increasing. In 1997, 52% of homes with central air conditioning report using it "all summer long, an increase from 33% in 1981. In 2005 air conditioning accounted for 3.07 quads of energy use which resulted in 187,784 thousand metric tons of CO2, 1,069 thousand metric tons of SO2 and 3,600 kilograms of mercury pollution in the atmosphere.

Most HVAC units use HFC-134a or HCFC-123 as their refrigerant. HFC-134a can achieve relatively high energy efficiency and is almost 100% ozone-safe (ODP=0.000014), but HFC-134a is a relatively potent greenhouse gas which is directly linked to global warming (GWP=1320). HCFC-123 can achieve high energy efficiency and is not a potent greenhouse gas (GWP=76), but it does have an ozone-depleting potential (ODP=.012). Neither of these refrigerants is environmentally benign and both of them will be phased out after the year 2020 when provisions of the Montreal Protocol regarding HCFC usage is enacted.

To address this problem the Stratos Company LLC is developing a very innovative water based vapor compressor system that will yield major air conditioning energy improvements of 30%. Our novel system will achieve these improvements in efficiency by utilizing refrigerant R718, which is simply water vapor. Benefits derived from our energy efficient technology include reduced green house gas emissions by 22 billion metric tons per year, a reduction in mercury emissions of 128 Kg per year, reduced dependence on imported fuels, and a reduced load on the electric grid. (These numbers are based on average emissions per unit of energy use and do not take into account additional benefits of reducing peak demand.)

I will be updating this weblog on R718 from time to time.

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Wednesday, April 5, 2006

Coral Die-Off

source: http://sustainabledesignupdate.com/?p=18

2005 saw the largest coral die-off ever recorded in the Caribbean, about a third of all coral in some study areas. In February NOAA reported 96 percent of lettuce coral, 93 percent of the star coral and nearly 61 percent of the brain coral in the St. Croix region had "bleached" (died). Coral provides a breeding ground for many species of fish and is the backbone of tourist and fishing industries.

It should be noted that last year saw unprecedented high temperatures in the Caribbean waters which produced a record number of hurricanes. And while things are bad in the Caribbean, they are worse in the Indian and Pacific oceans which have seen even greater loss of coral. Professor M. James Crabbe, an expert on corals world wide stated. €œIf you want to see a coral reef, go now, because they just won’t survive in their current state.

From the Environmental News Network:

It's an unprecedented die-off,€ said National Park Service fisheries biologist Jeff Miller, who last week checked 40 stations in the Virgin Islands.

“The mortality that we're seeing now is of the extremely slow-growing reef-building corals,€ Miller said. €œThese are corals that are the foundation of the reef colonies that were here when Columbus came by have died in the past three to four months.

Sunday, Edwin Hernandez-Delgado, a University of Puerto Rico biology researcher, found a colony of 800-year-old star coral that towered more than 13 feet high had recently died in waters off Puerto Rico.

Wednesday, Tyler Smith, coordinator of the U.S. Virgin Islands Coral Reef Monitoring Program, dived at a popular spot for tourists in St. Thomas and saw an old chunk of brain coral, about 3 feet in diameter, that was at least 90 percent dead from the disease called white plague.

We haven'€™t seen an event of this magnitude in the Caribbean before,€ said Mark Eakin, coordinator of the National Oceanic and Atmospheric Administration Coral Reef Watch.

For the Caribbean, it all started with hot sea temperatures, first in Panama in the spring and early summer, and got worse from there.

New NOAA sea-surface temperature figures show the sustained heating in the Caribbean last summer and fall was by far the worst in 21 years of satellite monitoring, Eakin said.

€œThe 2005 event is bigger than all the previous 20 years combined,€ he said. It remained hot for weeks, even months, stressing the coral.

CNN Science and Space reports similar findings here.

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Monday, March 27, 2006

Ethanol, Hydrogen and Carbon Disxide

source: http://sustainabledesignupdate.com/?p=14

Wild

Wild Grasses - Feedstock of the next industrial revolution?

Over the last week I have been thinking about everything ethanol. (No, this wasn't a lost weekend). The New York Times had an article on ethanol 3/26/06.

Background Ethanol is alcohol made from fermenting biological matter. Ethanol along with Bio-Diesel are two promising types of bio-fuels fuels derived from biological resources. Biofuels are renewable and if the chain of development from planting, through cultivation, harvesting and processing into useable fuel is carefully managed, biofuels can reduce the use of fossil energy, reduce pollution and increase our national security.

Ethanol has been in the news for a variety of reasons. First there have been some studies that show the net energy gain from the manufacture of ethanol is very little or worse yet, negative. Much of this negative chatter has come from conservative talk show hosts bemoaning farm subsidies for the production of ethanol from corn. However there are some new technologies on the horizon.

In their fall 2005 newsletter the Rocky Mountain Institute has a great article on Ethanol and best practices for development of an Ethanol infrastructure. As usual the RMI was ahead of the curve on this development. In their newsletter from the fall of 2005:

Switchgrass Biofuels, and specifically ethanol, have been the subject of a great deal of criticism in recent months by detractors claiming that more energy is required to produce ethanol than is available in the final product, that it is too expensive, and that it produces negligible carbon reductions. These critiques are simply not accurate. State-of-the-art technologies have been competently forecasted €even proven in the market to produce ethanol that is far more cost-effective and less energy-intensive than gasoline. We'€™ll explore why, and why the critics have gotten it wrong.

When we say biofuels, we mean liquid fuels made from biomass €chiefly biodiesel and ethanol, which can be substituted for diesel fuel or for gasoline, respectively. The technology used to produce biodiesel is well understood, although its biomass feedstocks are limited and production today is fairly expensive. We will instead focus on ethanol, which we believe has significantly greater potential.

But conventional processes and feedstocks used to make ethanol are not feasible in the United States on a large scale for three reasons: they're not cost-competitive with long-run gasoline prices without subsidies, they compete with food crops for land, and they have only marginally positive energy balances.

Happily, in addition to starch-based feedstocks, ethanol can be produced from cellulosic feedstocks, including biomass wastes, fast-growing hays like switchgrass, and short-rotation woody crops like poplar. While not cost-competitive today, already observed advances in technology lead us to believe that in the next few years, ethanol made from these crops will become cost-competitive, won'€™t compete with food for cropland, and will have a sizeable positive energy balance. Indeed, because these crops are expected to have big biomass yields (~10 15 dry tons/acre, up from the current ~5 dry tons/acre), much less land will be required than conventionally thought. Further, cellulosic ethanol will typically have twice the ethanol yield of corn-based ethanol, at lower capital cost, with far better net energy yield.

We can't remember how many times we'€™ve been asked the question: But doesn't ethanol require more energy to produce than it contains?€ The simple answer is no, €most scientific studies, especially those in recent years reflecting modern techniques, do not support this concern. These studies have shown that ethanol has a higher energy content than the fossil energy used in its production. Some studies that contend that ethanol is a net energy loser include (incorrectly) the energy of the sun used to grow a feedstock in ethanol™s energy balance, which misses the fundamental point that the sun’s energy is free. Furthermore, because crops like switchgrass are perennials, they are not replanted and cultivated every year, avoiding farm-equipment energy. Indeed, if polycultured to imitate the prairies where they grow naturally, they should require no fertilizer, irrigation, or pesticides either.

So, Cellulosic Ethanol could be a great way to reduce our dependence on Persian Gulf Oil.

A second technology that in my mind is linked to the potential of Cellulosic Ethanol is in development at the University of Minnesota. Dr. Lanny Schmidt has been developing a method of reforming alcohol into hydrogen using a very clever and simple technique. The core idea in his invention is to use a fuel injector to spray a fine spray of ethanol onto a catalyst. Water that naturally occurs in the ethanol turns to steam and this keeps the invention from exploding. (Apparently Dr. Schmidt had many a test rig explode in the lab!) With a carefully crafted catalyst the process runs clean and is very efficient.

Now, on one hand we have a new technology for the conversion of grasses and other agricultural waste into ethanol, and on the other hand we have a new technology for converting ethanol into hydrogen. This makes the possibility of using ethanol as a medium for storing hydrogen, and locally converting ethanol into hydrogen, say at the pump, a possibility. There are a lot of design decisions to make, like how to handle the CO2 that is generated as part of the conversion process. The overall process is close to carbon neutral but if we make high quality CO2 under controlled circumstances, then it seems like a good idea to sequester the CO2.

This leads to the third of the two technologies I wanted to write about today€œ Supercritical Carbon Dioxide. In the supercritical phase, that is when the pressure is really high, carbon dioxide can be in a phase right on the edge between gas and liquid. It can flow through a lot of materials and it is a highly polar solvent. SCCO2 can be used in some industrial processes as a solvent, or in certain processes it can react with some simple industrial waste products to make a form of carbonate mineral. This process makes a high quality form of pre-cast concrete. It can be used to make concrete block, concrete bricks, pre-cast stone or structural members. The process could sequester a couple of pounds of CO2 in every concrete block made with the process.

So, if you have Cellulosic Ethanol on one hand, a new highly efficient technology for the conversion of Ethanol to Hydrogen which leaves CO2 behind on your other hand, then on your third hand you have the SCCO2 conversion of industrial waste to carbonate minerals, you may have the makings of an entirely environmentally benign manufacturing/ industrial park.

I do plan on covering the SCCO2 process in an upcoming post. It is a lot like pre-cast concrete, only good for the environment.

Check out Cellulosic Ethanol at the Rocky Mountain Institute here.

Check out Dr. Schmidt at the Ethanol to Hydrogen technology here.

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Friday, March 24, 2006

New Global Warming Ads

source: http://sustainabledesignupdate.com/?p=13

Girl and Train

It is a rare event when the announcement of a new commercial makes my day seem brighter, but the Ad Council and the Environmental Defense Fund have put together a compelling new TV advertisement campaign similar to the litterbug and crying Indian campaigns of years ago. I have viewed the ads on You Tube, and I think they are the right message at the right time.

From the press release files at www.fightglobalwarming.com:

(Washington, D.C.) Environmental Defense and the Advertising Council are launching a series of television and radio public service announcements urging Americans to fight global warming in their everyday lives. The ad launch follows the release today of a nationwide survey that reveals that most Americans recognize the problem of global warming and are willing to help solve it by changing their daily habits to save energy and cut pollution.

The new global warming campaign marks a watershed moment in the effort to stir the public consciousness about global warming. The Ad Council has created some of the most iconic media campaigns of the past century, including Smokey Bear, Vince and Larry the Crash Test Dummies, Iron Eyes Cody (the Crying Indian), Friends Don't Let Friends Drive Drunk, and campaigns on polio, AIDS, and drug use. These and other Ad Council campaigns have been instrumental in elevating public awareness of serious issues and in bringing about social change.

Some of the world leading climate scientists endorsed the campaign, echoing the sentiments expressed by the University of Washington Dr. John Wallace: the risk of serious irreversible consequences within the next 30 years is too great to warrant complacency. All of us should be making personal choice to reduce unnecessary consumption of fossil fuels.€ In addition to Wallace, endorsers included Dr. John Holdren, Harvard University; Dr. Michael Oppenheimer, Princeton University; Nobelist Dr. Sherwood Rowland, University of California, Irvine; Dr. William Schlesinger, Duke University; Dr. Gavin Schmidt, NASA; and Dr. Steven Wofsy, Harvard University.

The new campaign's compelling advertisements, designed pro bono by New York ad firm Ogilvy and Mather, will be accompanied by a major public education effort including information about simple actions people can take to fight global warming. The campaign will offer a new guide targeted to consumers, The Low Carbon Diet. The campaign website, fightglobalwarming.com, also features interactive tools where people can calculate how much carbon pollution they produce in their everyday lives, and a series of simple energy-saving tips.

Links to â€Å"Tick” Video Ad (Streaming) , â€Å"Train” Video Ad (Streaming) |

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Wednesday, March 22, 2006

Signs for Climate Change

source: http://sustainabledesignupdate.com/?p=12

A recent article in Kathimerini, an English language Greek newspaper stated that 84% of the land of Greece is in danger of becomming a desert. This is due to salinization of the soil from over use of irrigation and other non-sustainable farming practices combined with changes in the climate.

An overwhelming 84 percent of Greeces land is at risk of desertification and another 8 percent is already arid but is being cultivated by farmers reluctant to lose their subsidies, according to scholars at a conference in Thessaloniki yesterday.

The threat of desertification is significant for over a third (35 percent) of Greek land and somewhat less so for another section accounting for half (49 percent) of the country, according to Constantinos Kosmas of Athens Agriculture University. The hardest-hit areas are believed to cover a large section of mainland Greece, most of the Peloponnese, mountainous parts of the Ionian islands, the islands of the Aegean, Evia, eastern and central Crete as well as parts of Thessaly, Macedonia and Thrace.

Kosmas stressed that the zones currently subject to only a moderate threat would face an immediate risk of desertification in the event of excessive agricultural exploitation or intense climate change.

Soil erosion constitutes the greatest danger for hilly land as it brings about a drastic reduction in the depth, fertility and productivity of earth and foliage, Kosmas said, stressing that agricultural machinery was also a prime culprit. Hilly sections of the Thessaly plain are currently at high risk of desertification because agricultural machines have displaced a layer of about 40 centimeters of earth, he said.

Kosmas also highlighted salination€ chiefly caused by irrigation using poor-quality water as a contributing factor to desertification.

A link to Kathimerini

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Wednesday, March 15, 2006

Scientists to Develop Bacteria-Powered Fuel Cells

source: http://www.physorg.com/news11772.html

A diverse team of microbiologists, engineers and geochemists from the University of Southern California and Rice University are joining forces to create bacteria-powered fuel cells that could power spy drones that fit in the palm of a hand.

The Air Force has long been interested in micro-scale air vehicles – some as small as insects – but it has been stymied by the lack of a suitable, compact power source. With $4.4 million from the Department of Defense's Multidisciplinary University Research Initiative, or MURI, the USC and Rice research team hopes to prove its concept valid within five years by producing a self-propelled prototype.


At Rice, geochemist Andreas Lüttge will spearhead the team's efforts to understand how the bacteria Shewanella oneidensis attach to and interact with anode surfaces inside the fuel cell. Anodes are the parts of fuel cells and batteries that gather excess electrons for harvesting. To optimize its design, the team must understand how bacteria transfer electrons to anode surfaces under a variety of conditions.

"There are three primary components in the system: the bacteria, the surface and the solution that the bacteria are digesting," said Lüttge, associate professor of earth science and chemistry. "Any change in one variable will affect the other two, and what we want to do is find out how to tweak each one to optimize the performance of the whole system."


Lüttge's participation in the program grew out of a decade-long collaboration with principal investigator Kenneth Nealson, USC's Wrigley Chair in Environmental Studies and Professor of Earth Sciences and Biological Sciences. Nealson helped pioneer the field of modern geobiology and the investigation of the genetic pathways that some microbes rely upon to maintain their respiratory metabolism in oxygen-poor environments. Shewanella oneidensis, one such bacterium, uses metals instead of oxygen to fully metabolize its food.

"Since this organism is capable of passing electrons directly to solid metal oxides, it is not particularly surprising that it can do the same to the anode of the fuel cell, and since we are already in the business of understanding and optimizing the metal reduction capacity, it seemed a reasonable step to apply the same approaches to understanding current production. What is new here is the incorporation of colleagues in chemistry, geology, engineering, and evolutionary biology to optimize the entire system, not just the bacteria."

In the fuel cell study, Lüttge will use computer models to estimate how the bacteria will behave under different circumstances. Running tests on the computer will save time and money by allowing laboratory experiments to focus on best candidate approaches.

"One of the hallmarks of our approach is the vigorous feedback between our computer models and our laboratory work," said Lüttge. "The computer simulations help us perform better experiments, and the laboratory tests help us design better simulation, and the overall combination saves time and money."

In addition to the computational modeling, Lüttge will contribute his experimental skills in an imaging technique called Vertical Scanning Interferometry. The technique, which he helped create in the 1990s, combines information from multiple beams of light to resolve sample features as small as one-billionth of a meter. In previous studies with Nealson, Lüttge used the technique to examine how the cigar-shaped Shewanella attach themselves to crystalline surfaces. The researchers found that Shewanella would lay flat and orient themselves relative to minute defects in the crystal's surface.

"We still have a lot to learn about the chemical cues that the Shewanella use - both individually and in colonies - but they are incredibly efficient at converting organic inputs to electricity, so we are confident that they'll be a great candidate for our fuel cells," Lüttge said.

Source: Rice University

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Friday, March 3, 2006

Antarctic ice sheet melting fast: scientists

source: http://www.abc.net.au/news/stories/2006/03/03/1583224.htm

Scientists say Antarctica's mammoth ice sheet is in "significant decline", probably due to climate change.

United States researchers at the University of Colorado at Boulder say online in the journal Science that the Antarctic ice sheet is losing up to 152 cubic kilometres of ice a year.

Dr Isabella Velicogna from the University's Cooperative Institute for Research in Environmental Sciences says it is the first study to indicate the total mass balance of the Antarctic ice sheet is in significant decline.

The team calculated the ice sheet lost 152 cubic kilometres a year from April 2002 to August 2005, give or take 80 cubic kilometres.

That is equivalent to global seas rising 0.4 millimetres a year, with a margin of error of 0.2 millimetres, the researchers say.

The bulk of the loss is occurring in the West Antarctic ice sheet, Dr Velicogna says, whose team used two satellites orbiting Earth in tandem to gather data.

The satellites estimate Earth's global gravity field and variations in the gravity field over time were used to determine changes in Earth's mass distribution, necessary for estimating changes in mass of the Antarctic ice sheet.

"The changes we are seeing are probably a good indicator of the changing climatic conditions there," Dr Velicogna said.

The study seems to contradict the 2001 assessment by the Intergovernmental Panel on Climate Change (IPCC), which forecast the Antarctic ice shelf would actually gain mass in the 21st Century due to higher precipitation in a warming climate.

The US researchers say the IPCC estimate was based on sparse coverage of coastal areas, which would have affected the results.

As Earth's fifth-largest continent, Antarctica is twice the size of Australia and contains 70 per cent of Earth's fresh water resources.

The ice sheet is an average 1,981 metres thick.

Research from the British Antarctic Survey suggests melting of the West Antarctic ice sheet alone would raise global sea levels by more than six metres.

--ABC Science Online/AFP

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