The U.S. Department of Energy’s National Renewable Energy Laboratory has developed a new air conditioning process with the potential of using 50 to 90 percent less energy than the best current units.

The process uses a unique combination of membranes, evaporative cooling and liquid desiccants. It uses the desiccant (highly concentrated aqueous salt solutions of lithium chloride or calcium chloride) to create dry air using heat and then uses evaporative cooling to make the dry air cold.

Engineers have known for decades the value of desiccants in air conditioning but, because of the complexity of desiccant cooling systems, they have traditionally only been used in industrial drying processes. To create a device simple enough for easy installation and maintenance, the NREL engineers used thin membranes that simplify the process of integrating air flow, desiccants and evaporative cooling. The air is cooled and dried from a hot-humid condition to a cold and dry condition all in one step.

Because the system uses salt solutions rather than refrigerants, there are no harmful chlorofluorocarbons (CFCs) or hydrochlorofluorocarbons (HCFCs).

The air conditioner uses very little electricity and can be powered by natural gas or solar electricity and will work in all climates.

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Green roofs are now required by law on all new buildings with roof slopes of less than 30 degrees in Copenhagen. It is hoped that as much as 5,000 square metres will be covered with new vegetation each year. The initiative is part of the city’s plan to become the world’s first totally carbon neutral city.

Toronto has also made green roofs compulsory but only on residential buildings that are at least six stories high.

A green roof on a building in Toronto

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One of the biggest challenges for architects and developers wanting to integrate solar power generation with building materials is aesthetics. Many building-integrated solar technologies are also somewhat inefficient, which means that large parts of a building have to be covered with solar energy-gathering materials to get significant benefits.

The Center for Architecture and Science, which is a research and development collaboration between Rensselaer Polytechnic Institute and architecture and engineering companies, including the architecture firm Skidmore, Owings & Merrill, thinks that its "Dynamic Solar Facade" can overcome these challenges.

The Dynamic Solar Facade is a glass frontage with rows of transparent, pyramid-shaped concentrators configured in a honeycomb pattern and hung on wires that move up and down, or twist side to side, to track the sun. Each concentrator has a lens that magnifies light nearly 500 times and directs it onto a solar cell made of gallium arsenide. The concentrators also bring light into the building while deflecting heat and glare, reducing the need for artificial light during the day.

The group claims that the Dynamic Solar Facade uses the sun’s light and heat with 60 to 80 percent efficiency.

The first full-scale demonstration project has just been installed  at the Syracuse Center of Excellence in Environmental and Energy Systems, which is scheduled to open in March. It comprises 64 concentrators in an 2.4-by-3-metres glass installation.

The Solar Facade is apparently stylish enough to satisfy the Fashion Institute of Technology in New York.which plans to include it in a new student centre.
 

(Image: Centre for Architecture and Science)

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Ice Energy, a  Colorado company, has signed a contract with the Southern California Public Power Authority to deploy rooftop units that use electricity at night to make ice. The ice is then used to cool buildings during the day.

The system effectively stores electricity made at night when demand and cost is low and uses it to reduce electricity demand on hot afternoons, when demand is at its peak.

Initially, 53 megawatts of storage will be installed on rooftops in the power authority’s service territory. The Los Angeles Department of Power and Water is the biggest user.

Christopher Hickman, a vice president of Ice Energy, said that his product would replace gas generators that might run only 5 percent of the hours in a year.

According to Bill D. Carnahan, the executive director of the Southern California Public Power Authority “The total 24-hour efficiency improvement is 8 percent”.

The ice storage units cost about $US2,000 per kilowatt of capacity.

(Based on sources including the New York Times)

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A Hamburg-based company, Thermodyna, has developed an air-conditioning system that uses only the sun’s heat to produce hot or cool air as required.

The core of the system is a Schukey motor. For cooling, a solar panel uses the sun’s heat to produce steam which is converted into mechanical energy. This drives a pump which sucks damp, warm air out of the room, compresses it and then allows it to expand. According to Thermodyna, the process can cool the air to around 20 degrees Celsius.

"There are no electronics and hardly any components," says Thermodyna boss Volker Bergholte. The company plans to begin selling the units in 2010.

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The Cement Sustainability Initiative (CSI), whose 18 members produce about 30 percent of the world’s cement, has unveiled its vision of a "sectoral approach" to tackling carbon dioxide.

The cement industry contributes about 5 percent of global carbon dioxide emissions and is expected to double its capacity by 2030 because of the rapid urbanization in developing countries.

CSI has developed a system for monitoring, reporting and verifying carbon dioxide emissions and aims to share technology and best practice for cutting those emissions. They claim that the proposed system could reduce emissions by as much as 25%, compared to taking no action.

Cement is made by heating limestone with clay minerals to produce an intermediate product called clinker. This process releases large amounts of carbon dioxide.

The CSI initiative would replace this clinker with residues from steel production and coal-fired power stations. Further cuts would be made by using biofuels to generate heat and by burying carbon dioxide using carbon capture and storage technologies.

Many environmentalists view industry initiatives such as this with skepticism after numerous voluntary agreements have failed to achieve significant results.

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Compact fluorescent light (CFL) bulbs do contain mercury, which is a harmful substance - but does that mean that they worse than incandescent light bulbs?

According to the US Environmental Protection Agency:, CFLs contain an average of about 4 milligrams of mercury sealed within the glass - that’s less than one percent of the mercury in mercury thermometers, which average about 500 milligrams. The amount of mercury in CFLs is continually being reduced. The best CFL bulbs now contain as little as 1.4 milligrams.

During its 8,000 hour lifetime, a 13-watt CFL will use 104 kilowatt hours of electricity. Producing this much electricity from coal releases 1.2 milligrams of mercury. The equivalent 60-watt incandescent light bulb will use 480 kilowatt hours of electricity which releases 5.8 milligrams of mercury. That is, generating the electricity to power an incandescent light releases more mercury than is contained in a typical CFL.

Of course, the mercury in a CFL is only released if it is smashed. If it is recycled, no mercury is released; if it is sent to landfill, an average of 0.6 milligrams of mercury is released to the atmosphere.

So, the CFL is the clear winner in terms of the amount of mercury released.

But how dangerous is mercury, anyway?

Click here to read the rest of this entry.

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Michael Palin, a student designer at the University of Western Sydney, has been shortlisted for an Australian Design Award for a neat and attractive way of adding double glazing in a rental property.

The "inflatable window" is actually a clear polycarbonate sheet which has the same look and feel as glass. The clear sheet is fitted to a frame that that. uses an inflatable rubber tube to seal it into the window reveal. The rubber tubing provides a 100% air tight seal without damaging the building in any way.

The frame hides the inside of the existing window and the architrave and can be designed in a range of styles and painted if desired.

The secondary window is held into the frame with magnets, so that it can be easily removed and the window opened.

The Australian Building Codes Board says that 87% of heat loss and 48% of heat gain is through windows. Installing inflatable windows has been shown to improve insulation by up to 50%.

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A Lawrence Berkeley National Laboratory scientist, Hashem Akbari, is poised to launch a campaign to paint the world white.

Inspired by the whitewashed villages around the Mediterranean, he argues that if we turn enough of the world’s dark urban landscape white, it would reflect sufficient sunlight to delay global warming and give us some precious breathing space in the global struggle to control carbon emissions.

Ola-Santorini Greece
(by Rambling Traveller via Wikimedia)

As well as reflecting more sunlight, buildings with white roofs stay cooler during the summer. The change also reduces the way heat accumulates in built-up areas - known as the urban heat island effect - and reduces the need for air-conditioning.

Click here to read the rest of this entry.

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The Mayor of Lomdon has launched a "Green Theatre Initiative", saying that that “the power of the theatre industry to set an example in the fight against climate change is immense”.

The Plan highlights a number of benefits to going green, firstly by allowing theatres to lead the way by “showing our audiences and other theatre industries what is possible.”  It points out the energy and money that can be saved, noting that a simple step such as ensuring that stage lights are only turned on half an hour before a performance would collectively save London theatres £100,000 a year in energy costs, and that such changes can be made without sacrificing artistic integrity.

In addition to a newsletter and information on its website, the Green Theatre Initiative will develop a database of sources where theatres can find funding and tax breaks for adopting green initiatives, and a compilation of proven methods that theatres can use to go green.

The Initiative was the idea of Gideon Banner, an actor known for performing with the Blue Man Group, so we can’t resist including a sample of their work.

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