Category Archives: Green Ideas

Hybrid power plants running on sun power

Posted on by
Reply

The success of hybrid cars is inspiring yet another way of going green but on a more ambitious scale harnessing solar energy to drive hybrid power plants under an India-Israel project. Avi Kribus, Professor of Mechanical Engineering at Tel Aviv University in Israel, inked the project with S Iniyan, Professor and Director, Institute of Energy Studies, Anna University, Chennai, in October last year to study how solar energy can augment power output. This collaboration is the outcome of a call for proposals for developing alternative energy sources by the Indian government’s department of science and technology and is funded by both the countries. “Sunlight can provide power and heat in amounts far surpassing all of humanity’s needs, but the prohibitively high production cost limits its use worldwide,” Iniyan told IANS . Production of solar-powered electricity “is still two to three times costlier than with fossil fuels,” said Iniyan. “This cost can be brought (down) to competitive levels if the conversion efficiency from sunlight to electricity is boosted and made available in a reliable way,” he added. In this context, the solar- powered steam injected gas turbine (STIG), a technology developed by Kribus, works with much lower steam pressures and temperatures than those required by conventional coal-fired plants. The proposed STIG cycle, which permits the solar part to use cheaper metals and low-cost solar collectors, can cut fossil fuel use by 25 to 50 per cent, bringing down production costs. It will drive hybrid power plants of tomorrow, which will be as competitive as coal-fired ones, according to Iniyan. Kribus explained, “We combine a gas turbine, which works on hot air, and not steam, and inject the solar-produced steam into the process.” “We still need to burn fuel to heat the air, but we add steam from low-temperature solar energy, approximately 200 degrees centigrade,” he added.

Green Dating sites

Posted on by
Reply

For the environmentally conscious soul in search of romance, here are reviews of some of the most popular online sites aimed at the green heart

Green friends: Claiming to be ‘the world’s first, largest and most effective site for singles green_datinginterested in vegetarianism or environmental protection’, Green Friends’ database is searchable only after joining. Membership appears small, but the site offers many features: sending a ‘wink’, blogs, greeting cards, forums, and linking to other friends in Facebook, MySpace and other community sites.

Green singles: Launched by a sweet looking couple in the 1980s first as a newsletter, then blossoming into a website, Green Singles boasts more than 15,000 members and success stories from recently married couples to punk rock teenagers enjoying their first experience of love.

Concerned singles: Launched in 1984, the site is home to mostly 50+ straight women interested in nature and meditation. Most are from America, but a few reside in other countries. If you’re a man looking for a female hiking enthusiast over 50, this site is where you should start.

Eco dater: A young but enthusiastic site, Eco Dater currently offers its premium membership free. This provides advanced search options and allows unlimited photos, along with its standard membership features of contacting other free members and contributing to the site’s blog. While the membership is relatively small, its pleasant interface, friendly attitude and encouragement of user feedback should quickly draw more users.

CO2 sucker could just clean the air

Posted on by
Reply

Researchers in California have produced a cheap plastic capable of removing large amounts of carbon dioxide (CO2) from the air. Down the road, the new material could enable the development of large-scale batteries and even form the basis of “artificial trees” that lower atmospheric concentrations of CO2 in an effort to stave off catastrophic climate change.

These long-term goals attracted the researchers, led by George Olah, a chemist at the University of Southern California (USC) in Los Angeles. Olah, who won the 1994 Nobel Prize in chemistry, has long envisioned future society relying primarily on fuel made from methanol, a simple liquid alcohol. As easily recoverable fossil fuels become scarce in the decades to come, he suggests that society could harvest atmospheric CO2 and combine it with hydrogen stripped from water to generate a methanol fuel for myriad uses.

Olah and his colleagues also work on making cheap, iron-based batteries that can store excess power generated by renewable energy sources and feed it into the electrical grid during times of peak demand. To function, the iron batteries grab oxygen from the air. But if even tiny amounts of CO2 get into the reaction, it kills the battery. In recent years, researchers have come up with good CO2 absorbers made from porous solids called zeolites and metal organic frameworks. But they’re expensive. So Olah and his colleagues set out to find a cheaper alternative.

They turned to polyethylenimine (PEI), a cheap polymer that is a decent CO2 absorber. But it only grabs CO2 at its surface. To boost PEI’s surface area, the USC team dissolved the polymer in a methanol solvent and spread it atop a batch of fumed silica, industrially produced porous solid made from microscopic droplets of glass fused together. When solvent evaporated, it left solid PEI with a high surface area.

When the researchers tested the new material’s CO2-grabbing abilities, they found that in humid air each gram of the material sopped up an average of 1.72 nanomoles of CO2. That’s above the 1.44 nanomoles per gram absorbed by a recent rival made from aminosilica and among the highest levels of CO2 absorption from air ever tested, the team reported in the Journal of the American Chemical Society. Once saturated with CO2, the PEI-silica combo is easy to regenerate. The CO2 floats away after polymer is heated to 85 degree Celsius. Other solid CO2 absorbers must be heated to over 800 degree Celsius to drive off the CO2.

Straw as Building Material for Future

Posted on by
1

A modern take on straw-bale construction may well be the grand design of the future if results coming out of the University of Bath are accepted by the construction industry. Think of a straw-bale house and you might imagine a tumbledown shack that leaks, creaks, slumps and smells somewhat of the farmyard. But step into Bale-Haus, a startlingly contemporary looking prototype home that has been built on the Bath Campus and there’s nary a wisp of straw to be seen. Instead, you are in a hallway of an upside down house with two bedrooms and a bathroom on the ground floor and an airy open plan living area upstairs. It feels like a little piece of Scandinavia has just arrived in Somerset, southwest England. The straw bales are all packed tightly inside a series of prefabricated rectangular wooden wall frames, which are then lime rendered, dried and finally slotted together like giant Lego pieces called ModCell panels.

People perceive straw houses as being a bit hippy and not particularly durable. Add to that the problems of getting mortgage – very few lenders will consider straw-bale construction. The benefits of straw, points out Professor Peter Walker, director of the University of Bath’s BRE Centre for Innovative Construction Materials, are that “it’s cheap, widely available and a good insulator. It’s been used in buildings houses for hundreds of years”.

The stack that remains after grain has been harvested – straw also helpfully soaks up carbon from the atmosphere and locks it in, so long as it is not allowed to decompose. For the building industry, which currently depends on materials with very high embedded energy costs -  concrete and brick are expensive in carbon terms both to make and to transport – straw could therefore offer a welcome solution to housing’s greenhouse gas emission.

The straw-bale house won’t get sopping wet in a thunderstorm or go up in a whoosh of flames if you knock over a candle. The results now being published by Walker and his research partner, Dr Katharine Beadle, who have spent the past 18 months testing the BaleHaus against an exhaustive list of risk factors that could rot it, burn it or blow it down, so far seem to be reassuring.

Beadle with his team took a ModCell unit to a test laboratory and tried to reduce it to ashes by strapping it to a fiery furnace and raising the temperature to over 1,000 degree Celsius. “It’s standard test to replicate a fire in a building.” explains Walker. “It means you know that a house will at least retain its structural integrity for half an hour, which gives people a chance to get out”. “It took an hour and a half of being in direct contact with the flames”, says Beadle, before the lime render began to drop off, “and then the straw did start to burn back, but because it’s so compacted it suffered more charring then actual disintegration.”

When it come to blowing the house down – hydraulic jacks were placed against the walls to replicate wind forces pushing against the bales – the ModCell panels moved a few millimeters, but stayed within the tolerances allowed for by the computer modeling carried out prior to its construction. That says Walker, could be very good news for the price of the eventual ModCell building system. “It means the house is stiffer than it needs to be.” The approximate cost of the current modular building system for this design is £132,000 from above the concrete slab. “Cost is a challenge to the introduction of this technology but as a prototype house I think it stacks up well,” said Walker. “The aspiration is that it should be cost competitive with more savings coming through reduced heating bills.”

To replicate the heat given off by humans and appliances arrays of incandescent light bulbs on timers blaze in every room at pre-programmed times of day “to see how much heat escapes, and what level of heating would be needed at different times of the year,” explains Beadle.

“That environmental modeling will give us all the numbers about the energy the house is predicted to use. And if we are predicting how it will operate in given climate change, we can then put in those variables.”

Sensors embedded within each wall panel constantly monitor the degree of moisture absorbed and then released back through the breathable lime render into the sir outside by the panels. And on the air tightness test that was carried out, BaleHaus came in way under the building regulations threshold, and did considerably better than the far lowest “best practice” standard.

- The Guardian