Researchers Aim To Harvest Solar Energy From Pavement To Melt Ice, Power Streetlights

The heat radiating off roadways has long been a factor in explaining why city temperatures are often considerably warmer than nearby suburban or rural areas. Now a team of engineering researchers from the University of Rhode Island is examining methods of harvesting that solar energy to melt ice, power streetlights, illuminate signs, heat buildings and potentially use it for many other purposes.

“We have mile after mile of asphalt pavement around the country, and in the summer it absorbs a great deal of heat, warming the roads up to 140 degrees or more,” said K. Wayne Lee, URI professor of civil and environmental engineering and the leader of the joint project. “If we can harvest that heat, we can use it for our daily use, save on fossil fuels, and reduce global warming.”

The URI team has identified four potential approaches, from simple to complex, and they are pursuing research projects designed to make each of them a reality.

One of the simplest ideas is to wrap flexible photovoltaic cells around the top of Jersey barriers dividing highways to provide electricity to power streetlights and illuminate road signs. The photovoltaic cells could also be embedded in the roadway between the Jersey barrier and the adjacent rumble strip.

“This is a project that could be implemented today because the technology already exists,” said Lee. “Since the new generation of solar cells are so flexible, they can be installed so that regardless of the angle of the sun, it will be shining on the cells and generating electricity. A pilot program is progressing for the lamps outside Bliss Hall on campus.”

Another practical approach to harvesting solar energy from pavement is to embed water filled pipes beneath the asphalt and allow the sun to warm the water. The heated water could then be piped beneath bridge decks to melt accumulated ice on the surface and reduce the need for road salt. The water could also be piped to nearby buildings to satisfy heating or hot water needs, similar to geothermal heat pumps. It could even be converted to steam to turn a turbine in a small, traditional power plant.

Graduate student Andrew Correia has built a prototype of such a system in a URI laboratory to evaluate its effectiveness, thanks to funding from the Korea Institute for Construction Technology. By testing different asphalt mixes and various pipe systems, he hopes to demonstrate that the technology can work in a real world setting.

“One property of asphalt is that it retains heat really well,” he said, “so even after the sun goes down the asphalt and the water in the pipes stays warm. My tests showed that during some circumstances, the water even gets hotter than the asphalt.”

A third alternative uses a thermo-electric effect to generate a small but usable amount of electricity. When two types of semiconductors are connected to form a circuit linking a hot and a cold spot, there is a small amount of electricity generated in the circuit.

URI Chemistry Professor Sze Yang believes that thermo-electric materials could be embedded in the roadway at different depths — or some could be in sunny areas and others in shade — and the difference in temperature between the materials would generate an electric current. With many of these systems installed in parallel, enough electricity could be generated to defrost roadways or be used for other purposes. Instead of the traditional semiconductors, he proposes to use a family of organic polymeric semiconductors developed at his laboratory that can be fabricated inexpensively as plastic sheets or painted on a flexible plastic sheet.

“This is a somewhat futuristic idea, since there isn’t any practical device on the market for doing this, but it has been demonstrated to work in a laboratory,” said Yang. “With enough additional research, I think it can be implemented in the field.”

Perhaps the most futuristic idea the URI team has considered is to completely replace asphalt roadways with roadways made of large, durable electronic blocks that contain photovoltaic cells, LED lights and sensors. The blocks can generate electricity, illuminate the roadway lanes in interchangeable configurations, and provide early warning of the need for maintenance.

According to Lee, the technology for this concept exists, but it is extremely expensive. He said that one group in Idaho made a driveway from prototypes of these blocks, and it cost about $100,000. Lee envisions that corporate parking lots may become the first users of this technology before they become practical and economical for roadway use.

“This kind of advanced technology will take time to be accepted by the transportation industries,” Lee said. “But we’ve been using asphalt for our highways for more than 100 years, and pretty soon it will be time for a change.”

Todd McLeish @ University of Rhode Island ?

Researchers Find A Stable Way To Store The Sun's Heat

There should be an image here!Researchers at MIT have revealed exactly how a molecule called fulvalene diruthenium, which was discovered in 1996, works to store and release heat on demand. This understanding, reported in a paper published on Oct. 20 in the journal Angewandte Chemie, should make it possible to find similar chemicals based on more abundant, less expensive materials than ruthenium, and this could form the basis of a rechargeable battery to store heat rather than electricity.

The molecule undergoes a structural transformation when it absorbs sunlight, putting it into a higher-energy state where it can remain stable indefinitely. Then, triggered by a small addition of heat or a catalyst, it snaps back to its original shape, releasing heat in the process. But the team found that the process is a bit more complicated than that.

“It turns out there’s an intermediate step that plays a major role,” said Jeffrey Grossman, the Carl Richard Soderberg Associate Professor of Power Engineering in the Department of Materials Science and Engineering. In this intermediate step, the molecule forms a semi-stable configuration partway between the two previously known states. “That was unexpected,” he said. The two-step process helps explain why the molecule is so stable, why the process is easily reversible and also why substituting other elements for ruthenium has not worked so far.

In effect, explained Grossman, this process makes it possible to produce a “rechargeable heat battery” that can repeatedly store and release heat gathered from sunlight or other sources. In principle, Grossman said, a fuel made from fulvalene diruthenium, when its stored heat is released, “can get as hot as 200 degrees C, plenty hot enough to heat your home, or even to run an engine to produce electricity.”

Compared to other approaches to solar energy, he said, “it takes many of the advantages of solar-thermal energy, but stores the heat in the form of a fuel. It’s reversible, and it’s stable over a long term. You can use it where you want, on demand. You could put the fuel in the sun, charge it up, then use the heat, and place the same fuel back in the sun to recharge.”

In addition to Grossman, the work was carried out by Yosuke Kanai of Lawrence Livermore National Laboratory, Varadharajan Srinivasan of MIT’s Department of Materials Science and Engineering, and Steven Meier and Peter Vollhardt of the University of California, Berkeley.

The problem of ruthenium’s rarity and cost still remains as “a dealbreaker,” Grossman said, but now that the fundamental mechanism of how the molecule works is understood, it should be easier to find other materials that exhibit the same behavior. This molecule “is the wrong material, but it shows it can be done,” he said.

The next step, he said, is to use a combination of simulation, chemical intuition, and databases of tens of millions of known molecules to look for other candidates that have structural similarities and might exhibit the same behavior. “It’s my firm belief that as we understand what makes this material tick, we’ll find that there will be other materials” that will work the same way, Grossman said.

Grossman plans to collaborate with Daniel Nocera, the Henry Dreyfus Professor of Energy and Professor of Chemistry, to tackle such questions, applying the principles learned from this analysis in order to design new, inexpensive materials that exhibit this same reversible process. The tight coupling between computational materials design and experimental synthesis and validation, he said, should further accelerate the discovery of promising new candidate solar thermal fuels.

Source: “Mechanism of Thermal Reversal of the (Fulvalene) tetracarbonyldiruthenium Photoisomerization: Toward Molecular Solar-Thermal Energy Storage,” by Yosuke Kanai, Varadharajan Srinivasan, Steven K. Meier, K. Peter C. Vollhardt, Jeffrey C. Grossman. Angewandte Chemie, 20 October, 2010.

[Photo above by Mike Baird / CC BY-ND 2.0]

Jen Hirsch @ Massachusetts Institute of Technology

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Water-Based Artificial Leaf Produces Electricity

There should be an image here!A team led by a North Carolina State University researcher has shown that water-gel-based solar devices — “artificial leaves” — can act like solar cells to produce electricity. The findings prove the concept for making solar cells that more closely mimic nature. They also have the potential to be less expensive and more environmentally friendly than the current standard-bearer: silicon-based solar cells.

The bendable devices are composed of water-based gel infused with light-sensitive molecules — the researchers used plant chlorophyll in one of the experiments — coupled with electrodes coated by carbon materials, such as carbon nanotubes or graphite. The light-sensitive molecules get “excited” by the sun’s rays to produce electricity, similar to plant molecules that get excited to synthesize sugars in order to grow, says NC State’s Dr. Orlin Velev, Invista Professor of Chemical and Biomolecular Engineering and the lead author of a paper published online in the Journal of Materials Chemistry describing this new generation of solar cells.

Velev says that the research team hopes to “learn how to mimic the materials by which nature harnesses solar energy.” Although synthetic light-sensitive molecules can be used, Velev says naturally derived products — like chlorophyll — are also easily integrated in these devices because of their water-gel matrix.

Now that they’ve proven the concept, Velev says the researchers will work to fine-tune the water-based photovoltaic devices, making them even more like real leaves.

“The next step is to mimic the self-regenerating mechanisms found in plants,” Velev says. “The other challenge is to change the water-based gel and light-sensitive molecules to improve the efficiency of the solar cells.”

Velev even imagines a future where roofs could be covered with soft sheets of similar electricity-generating artificial-leaf solar cells.

“We do not want to overpromise at this stage, as the devices are still of relatively low efficiency and there is a long way to go before this can become a practical technology,” Velev says. “However, we believe that the concept of biologically inspired ‘soft’ devices for generating electricity may in the future provide an alternative for the present-day solid-state technologies.”

Researchers from the Air Force Research Laboratory and Chung-Ang University in Korea co-authored the study. The study was funded by the Air Force Research Laboratory and the U.S. Department of Energy. The work is part of NC State’s universitywide nanotechnology program, [email protected] State.

NC State’s Department of Chemical and Biomolecular Engineering is part of the university’s College of Engineering.

[Photo above by nedrichards / CC BY-ND 2.0]

Mick Kulikowski @ North Carolina State University

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Major Hurdle Cleared For Organic Solar Cells

There should be an image here!Solar energy is an environmentally friendly way of producing electricity and is considered to be one of the most appealing options for the future.

The basis for solar energy is absorbing light and then effectively disassociating electrical charges. As Yana Vaynzof, a University of Cambridge researcher, reports in the American Institute of Physics’ Applied Physics Letters, conjugated polymers are excellent materials for such a system, thanks to their light absorption and conduction properties. Unfortunately, poor charge disassociation in these materials tends to inhibit their performance. Photo-induced charges remain closely bound and recombine before they can be collected for electricity.

With a goal of working around this, Vaynzof and colleagues studied the charge disassociation at an interface between an organic polymer, in which the light is absorbed, and an inorganic oxide layer.

“In particular, we discovered that modifying the interface with a self-assembled monolayer of molecules results in an increase of charge disassociation efficiency to nearly 100 percent,” says Vaynzof. “Our measurements revealed that the molecular modification alters the energetic landscape of the interface so that the light absorbed in its vicinity is disassociated into charges that are then swept far from each other — preventing them from recombination, much like two balls rolling away from each other on opposite sides of a hill.”

This has significant implications for the organic solar cell industry because it offers an interesting solution to one of the field’s most significant problems.

[Photo above by jalalspages / CC BY-ND 2.0]

Jason Bardi @ American Institute of Physics

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Molecules Found In Blue Jean And Ink Dyes May Lead To More Efficient Solar Cells

There should be an image here!Cornell University researchers have discovered a simple process — employing molecules typically used in blue jean and ink dyes — for building an organic framework that could lead to economical, flexible and versatile solar cells. The discovery is reported in the journal Nature Chemistry.

Today’s heavy silicon panels are effective, but they can also be expensive and unwieldy. Searching for alternatives, William Dichtel, assistant professor of chemistry and chemical biology, and Eric L. Spitler, a National Science Foundation American Competitiveness in Chemistry Postdoctoral Fellow at Cornell, employed a strategy that uses organic dye molecules assembled into a structure known as a covalent organic framework (COF). Organic materials have long been recognized as having potential to create thin, flexible and low-cost photovoltaic devices, but it has been proven difficult to organize their component molecules reliably into ordered structures likely to maximize device performance.

“We had to develop a completely new way of making the materials in general,” Dichtel said. The strategy uses a simple acid catalyst and relatively stable molecules called protected catechols to assemble key organic molecules into a neatly ordered two-dimensional sheet. These sheets stack on top of one another to form a lattice that provides pathways for charge to move through the material.

The reaction is also reversible, allowing for errors in the process to be undone and corrected. “The whole system is constantly forming wrong structures alongside the correct one,” Dichtel said, “but the correct structure is the most stable, so eventually, the more perfect structures end up dominating.” The result is a structure with high surface area that maintains its precise and predictable molecular ordering over large areas.

The researchers used x-ray diffraction to confirm the material’s molecular structure and surface area measurements to determine its porosity.

At the core of the framework are molecules called phthalocyanines, a class of common industrial dyes used in products from blue jeans to ink pens. Phthalocyanines are also closely related in structure to chlorophyll, the compound in plants that absorbs sunlight for photosynthesis. The compounds absorb almost the entire solar spectrum — a rare property for a single organic material.

“For most organic materials used for electronics, there’s a combination of some design to get the materials to perform well enough, and there’s a little bit of an element of luck,” Dichtel said. “We’re trying to remove as much of that element of luck as we can.”

The structure by itself is not a solar cell yet, but it is a model that will significantly broaden the scope of materials that can be used in COFs, Dichtel said. “We also hope to take advantage of their structural precision to answer fundamental scientific questions about moving electrons through organic materials.”

Once the framework is assembled, the pores between the molecular latticework could potentially be filled with another organic material to form a light, flexible, highly efficient and easy-to-manufacture solar cell. The next step is to begin testing ways of filling in the gaps with complementary molecules.

Blaine Friedlander @ Cornell University

[Photo above by *Zara / CC BY-ND 2.0]

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Researchers Clear Major Hurdle In Road To High-Efficiency Solar Cells

There should be an image here!A team of University of Minnesota-led researchers has cleared a major hurdle in the drive to build solar cells with potential efficiencies up to twice as high as current levels, which rarely exceed 30 percent.

By showing how energy that is now being lost from semiconductors in solar cells can be captured and transferred to electric circuits, the team has opened a new avenue for solar cell researchers seeking to build cheaper, more efficient solar energy devices. The work is published in this week’s Science.

A system built on the research could also slash the cost of manufacturing solar cells by removing the need to process them at very high temperatures.

The achievement crowns six years of work begun at the university Institute of Technology (College of Science and Engineering) chemical engineering and materials science professors Eray Aydil and David Norris and chemistry professor Xiaoyang Zhu (now at the university of Texas-Austin) and spearheaded by U of M graduate student William Tisdale.

In most solar cells now in use, rays from the sun strike the uppermost layer of the cells, which is made of a crystalline semiconductor substance — usually silicon. The problem is that many electrons in the silicon absorb excess amounts of solar energy and radiate that energy away as heat before it can be harnessed.

An early step in harnessing that energy is to transfer these “hot” electrons out of the semiconductor and into a wire, or electric circuit, before they can cool off. But efforts to extract hot electrons from traditional silicon semiconductors have not succeeded.

However, when semiconductors are constructed in small pieces only a few nanometers wide — “quantum dots” — their properties change.

“Theory says that quantum dots should slow the loss of energy as heat,” said Tisdale. “And a 2008 paper from the University of Chicago showed this to be true. The big question for us was whether we could also speed up the extraction and transfer of hot electrons enough to grab them before they cooled.”

In the current work, Tisdale and his colleagues demonstrated that quantum dots — made not of silicon but of another semiconductor called lead selenide — could indeed be made to surrender their “hot” electrons before they cooled. The electrons were pulled away by titanium dioxide, another common inexpensive and abundant semiconductor material that behaves like a wire.

“This is a very promising result,” said Tisdale. “We’ve shown that you can pull hot electrons out very quickly — before they lose their energy. This is exciting fundamental science.”

The work shows that the potential for building solar cells with efficiencies approaching 66 percent exists, according to Aydil.

“This work is a necessary but not sufficient step for building very high-efficiency solar cells,” he said. “It provides a motivation for researchers to work on quantum dots and solar cells based on quantum dots.”

The next step is to construct solar cells with quantum dots and study them. But one big problem still remains: “Hot” electrons also lose their energy in titanium dioxide. New solar cell designs will be needed to eliminate this loss, the researchers said.

Still, “I’m comfortable saying that electricity from solar cells is going to be a large fraction of our energy supply in the future,” Aydil noted.

The research was funded primarily by the U.S. Department of Energy and partially by the National Science Foundation. Other authors of the paper were Brooke Timp from the University of Minnesota and Kenrick Williams from UT-Austin.

Preston Smith @ University of Minnesota

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Panasonic Provides Home Dwellers With A New Sense Of Power

This is just cool, no two ways about it. Speaking as a guy who would love to get off the grid to a degree but not have to forgo the niceties of electricity, this battery sounds awesome. Okay, so it’s a  battery — big deal! Actually, it could be a very big deal.

As outlined in the piece linked above, this battery could provide the missing link with solar energy in powering homes. Hence, batteries that actually store enough energy effectively. Then there is price. Assuming pricing can be kept out of orbit for the typical home owner, then we might very well see these batteries teaming up with the various solar panel projects out there.

For myself personally, my interest in anything solar is due to potential for cost savings, assuming the cost of equipment came down to Earth. While still out of reach at this point, I feel confident that efforts like the Panasonic battery are where the future is at. After all, how cool would it be to get a check from the power company for giving them power! It happens, be it rarely.

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1955: First Solar-Powered Car Demonstrated

Today in 1955, William G. Cobb demonstrated the first solar-powered car at General Motors’ Powerama exhibition in Chicago. Almost 60 years later, we’ve still not managed to efficiently harness the potential of solar power on a grand scale — but this alternative source of energy can be utilized in a number of ways by any individual willing to tinker.

There should be an image here!Let the sun shine on your evil side — and have a wicked amount of fun on your way to becoming a solar energy master! In this guide, the popular Evil Genius format ramps up your understanding of powerful, important, and environmentally friendly solar energy — and shows you how to build real, practical solar energy projects you can use in your home, yard — even on the road!

In Solar Energy Projects for the Evil Genius, high-tech guru Gavin Harper gives you everything you need to build more than 50 thrilling solar energy projects. You’ll find complete, easy-to-follow plans, with clear diagrams and schematics, so you know exactly what’s involved before you begin.

There should be an image here!Want to take advantage of solar power in your home? Whether you’re looking to save on your energy costs by adding a few solar components or you want to build a solar-powered house from the ground up, Solar Power For Dummies takes the mystery out of this energy source and shows you how to put it to work for you!

This friendly, hands-on guide is packed with tips for making your home more energy-efficient though solar power — and helping the planet at the same time. You’ll see how to survey your home to determine your current household energy efficiency and use, and evaluate where solar power would best benefit you. You’ll also calculate what the return on your investment will be before you make any decisions. Once you’ve decided on a project, you’ll see whether it’s best to hire a contractor or do it yourself.

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The XPower Powerpack Solar is the first portable power pack that incorporates solar power in a compact, portable power source. It’s completely self-renewing, which means the detachable 5-watt solar panel has the ability to recharge the power pack’s 10 amp-hour battery. The 5-watt solar panel captures, stores, and converts the sun’s renewable energy, replenishes the XPower Powerpack Solar’s battery, and extends the runtime of many devices by up to 25 percent.

Product Features: Runs 120-volt AC or 12-volt DC products anywhere Built-in 400-watt inverter Sealed, non-spillable 10 amp-hour AGM battery Two 120-volt AC outlets, one 12-volt DC socket and one USB port Three-digit display for easy battery status monitoring Rubberized protection to guard against unit slipping AC charger included so you can charge from a standard wall outlet DC charger included so you can charge from a vehicle or RV Applications: Operates and charges a portable DVD player, 13-inch color TV, laptop, portable stereo, cordless phone, portable cooler and air compressor. Operates multiple products simultaneously.

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The Thames & Kosmos Fuel Cell Car and Experiment Kit provide a playful introduction to one of the most significant technologies of the early 21st Century. With this kit you can build a model car that actually runs on water. First, add water and watch it separate into hydrogen and oxygen. Then, use those stored gases to power your vehicle across the floor. Now that we have your attention, roll up your sleeves and find out more through experiments and demonstrations you can do on your own, in a classroom or with friends.

With this unique kit, you can build your own experimental reversible fuel cell car to learn more about this energy source. With more than 30 experiments and demonstrations, users will learn how a reversible fuel cell works to perform electrolysis as well as to create energy. The electricity required to activate electrolysis is created with a large solar cell included with the kit. During electrolysis, water is separated into hydrogen and oxygen and the resulting energy is stored as a gas. When needed, the gas is fed into the fuel cell, which then serves as the power source.

How To Design A Solar-Powered Computing Device

There should be an image here!Learn the great strides being made in solar-powered computing devices.

Going beyond useful gadgets powered by the sun, solar-powered computing devices are just over the horizon. Imagine network routers and surveillance devices soaking up the sun and running networking, video and security software. Free of power and Ethernet cables, these embedded systems can be deployed in the field quickly and cheaply.

This free white paper describes different types of embedded solar-powered computing devices and provides design suggestions for Intel Atom processor based platforms. It covers hardware and software practices for developing ultra-low power devices, as well as open source software available to designers.

Get your free white paper, How to Design a Solar-Powered Computing Device, today!

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Solar Energy Projects For The Evil Genius

There should be an image here!Let the sun shine on your evil side – and have a wicked amount of fun on your way to becoming a solar energy master! In this guide, the popular Evil Genius format ramps up your understanding of powerful, important, and environmentally friendly solar energy – and shows you how to build real, practical solar energy projects you can use in your home, yard – even on the road!

In Solar Energy Projects for the Evil Genius, high-tech guru Gavin Harper gives you everything you need to build more than 30 thrilling solar energy projects. You’ll find complete, easy-to-follow plans, with clear diagrams and schematics, so you know exactly what’s involved before you begin.

  • Illustrated instructions and plans for 30 amazing pretested solar energy projects that assume no prior experience with energy science
  • Explanations of the science and math behind each project
  • Projects that progress in difficulty – from simple ones that may inspire science fair entries – all the way to converting a real home to solar energy
  • Frustration-factor removal-needed parts are listed, along with sources-plus all the tools you’ll need

Solar Energy Projects for the Evil Genius provides you with complete plans, instructions, parts lists, and sources for:

  • Crushed berries solar cell
  • Solar “death ray”
  • Solar powered hot dog cooker
  • Solar furnace
  • Sun-powered refrigerator
  • Camping shower, oven, and more
  • Hot recipes for solar cooking
  • Water purifier
  • Flashlight
  • Garden lights
  • Solar vehicle
  • Environmentally friendly robot
  • Much more!

[tags]solar power, alternative energy[/tags]

Three Free Months of Web Hosting

Imagine my surprise when we were contacted by a Web hosting company with a killer deal (from out of the blue, although the owners have been long-time Lockergnome fans). Yeah, the three free months of Web hosting is a pretty good deal, but I think in the underlying mechanism is where the true story sits:

ThinkHost’s Smart Essentials package is perfect for a small business, community or personal web site. With its low price, generous allowances, plus Microsoft FrontPage and PHP-MySQL hosting support standard, this is the perfect package for most sites. There’s also the added advantage of knowing that our services are powered by 100% wind/solar energy – it’s earth friendly hosting!

The vast majority of our staff “telecommutes” to work – no wasting of fossil fuels or contributing to global warming through trips to and from work. We use little in the way of paper as data is stored electronically. Most of our staff use notebook computers and low wattage lighting, reducing electricity requirements. What electricity we do use, including the amount used by our servers, is 100% powered by renewable energy – a wind/solar mix! We also donate a substantial amount each year in free hosting services to environmental groups!

Continue reading “Three Free Months of Web Hosting”