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thinkahol *

Two-layer solar cell to achieve 42 percent efficiency | KurzweilAI - 0 views

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    In a paper published in Nature Photonics, University of Toronto researchers report the first efficient two-layer solar cell based on colloidal quantum dots (CQD) to capture both visible and near-infrared rays. CQDs are nanoscale materials that can be tuned to respond to specific wavelengths of the visible and invisible spectrum. By capturing such a broad range of light waves - wider than normal solar cells - tandem CQD solar cells can in principle reach up to 42 per cent efficiencies. The best single-junction solar cells are constrained to a maximum of 31 per cent efficiency. (In reality, solar cells that are on the roofs of houses and in consumer products have 14 to 18 per cent efficiency.) The researchers expect that in five years, solar cells using the graded recombination layer paper will be integrated into building materials and mobile devices.
thinkahol *

Dr. Daniel G. Nocera - YouTube - 0 views

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    The supply of secure, clean, sustainable energy is arguably the most important scientific and technical challenge facing humanity in the 21st century. Rising living standards of a growing world population will cause global energy consumption to double by mid-century and triple by the end of the century. Even in light of unprecedented conservation, the additional energy needed is simply not attainable from long discussed sources these include nuclear, biomass, wind, geothermal and hydroelectric. The global appetite for energy is simply too much. Petroleum-based fuel sources (i.e., coal, oil and gas) could be increased. However, deleterious consequences resulting from external drivers of economy, the environment, and global security dictate that this energy need be met by renewable and sustainable sources. The dramatic increase in global energy need is driven by 3 billion low-energy users in the non-legacy world and by 3 billion people yet to inhabit the planet over the next half century. The capture and storage of solar energy at the individual level personalized solar energy drives inextricably towards the heart of this energy challenge by addressing the triumvirate of secure, carbon neutral and plentiful energy. This talk will place the scale of the global energy issue in perspective and then discuss how personalized energy (especially for the non-legacy world) can provide a path to a solution to the global energy challenge. Daniel G. Nocera is the Henry Dreyfus Professor of Energy at the Massachusetts Institute of Technology, Director of the Solar Revolutions Project and Director of the Eni Solar Frontiers Center at MIT. His group pioneered studies of the basic mechanisms of energy conversion in biology and chemistry. He has recently accomplished a solar fuels process that captures many of the elements of photosynthesis outside of the leaf. This discovery sets the stage for a storage mechanism for the large scale, distributed, deployment of solar energy. He has b
thinkahol *

Hybrid solar system makes rooftop hydrogen | KurzweilAI - 0 views

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    Duke University engineer Nico Hotz has proposed a hybrid solar system in which sunlight heats a combination of water and methanol in a maze of tubes on a rooftop to produce hydrogen. The device is a series of copper tubes coated with a thin layer of aluminum and aluminum oxide and partly filled with catalytic nanoparticles. A combination of water and methanol flows through the tubes, which are sealed in a vacuum. Once the evaporated liquid achieves higher temperatures, tiny amounts of a catalyst are added, which produces hydrogen. This combination of high temperature and added catalysts produces hydrogen very efficiently, Hotz said. The resulting hydrogen can then be immediately directed to a fuel cell to provide electricity to a building during the day, or compressed and stored in a tank to provide power later. After two catalytic reactions, the system produced hydrogen much more efficiently than current technology without significant impurities, Hotz said. The resulting hydrogen can be stored and used on demand in fuel cells. "This set-up allows up to 95 percent of the sunlight to be absorbed with very little being lost as heat to the surroundings," he said. "This is crucial because it permits us to achieve temperatures of well over 200 degrees Celsius within the tubes. By comparison, a standard solar collector can only heat water between 60 and 70 degrees Celsius." Holtz performed a cost analysis, comparing a standard photovoltaic cell, a photocatalytic system, and the hybrid solar-methanol system.  He found that the hybrid system is the least expensive solution, with a total installation cost of $7,900 if designed to fulfill the requirements in summer. The paper describing the results of Hotz's analysis was named the top paper during the ASME Energy Sustainability Fuel Cell 2011 conference in Washington, D.C. Topics: Energy | Nanotech/Materials Science
Philip Solars

Go Solar Today! - 1 views

started by Philip Solars on 29 Nov 12 no follow-up yet
Philip Solars

The Must Have Solar Equipment - 0 views

started by Philip Solars on 28 Sep 12 no follow-up yet
thinkahol *

New way to store solar energy for use whenever it's needed | KurzweilAI - 0 views

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    MIT researchers have developed a new application of carbon nanotubes that shows promise as an innovative approach to storing solar energy for use whenever it's needed. Storing the sun's heat in chemical form - rather than first converting it to electricity or storing the heat itself in a heavily insulated container - has significant advantages: in principle, the chemical material can be stored for long periods of time without losing any of its stored energy. The researchers created carbon nanotubes in combination with a compound called azobenzene. The resulting molecules, produced using nanoscale templates to shape and constrain their physical structure, and the concept that can be applied to many new materials. This material is vastly more efficient at storing energy in a given amount of space - about 10,000 times higher in volumetric energy density, making its energy density comparable to lithium-ion batteries, the researchers said. Ref.: Alexie M. Kolpak, Jeffrey C. Grossman, Azobenzene-Functionalized Carbon Nanotubes As High-Energy Density Solar Thermal Fuels, Nano Letters, 2011; 110705085331088 [DOI: 10.1021/nl201357n]
Philip Solars

The Right Solar Panel! - 1 views

started by Philip Solars on 20 Nov 12 no follow-up yet
thinkahol *

New solar cell: Engineers crack full-spectrum solar challenge - 0 views

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    ScienceDaily (June 26, 2011) - In a paper published in Nature Photonics, U of T Engineering researchers report a new solar cell that may pave the way to inexpensive coatings that efficiently convert the sun's rays to electricity.
thinkahol *

Highly efficient solar cells could result from quantum dot research - 0 views

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    ScienceDaily (June 18, 2010) - Conventional solar cell efficiency could be increased from the current limit of 30 percent to more than 60 percent, suggests new research on semiconductor nanocrystals, or quantum dots, led by chemist Xiaoyang Zhu at The University of Texas at Austin.
thinkahol *

Stamping out low-cost nanodevices | KurzweilAI - 0 views

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    A simple technique for stamping patterns invisible to the human eye onto a special class of nanomaterials has been developed by researchers at Vanderbilt University. The new method works with porous nanomaterials that are riddled with tiny voids, which give them unique optical, electrical, chemical, and mechanical properties. There are nanoporous forms of gold, silicon, alumina, and titanium oxide, among others. The technique involves the creation of pre-mastered stamps using traditional, but complex, clean room processes and then using the stamps to create patterns using a new process called direct imprinting of porous substrates (DIPS). DIPS can create a device in less than a minute, regardless of its complexity. The smallest pattern the researchers have made to date has features of only a few tens of nanometers (about the size of a single fatty acid molecule). They have also succeeded in imprinting the smallest pattern yet reported in nanoporous gold, one with 70-nanometer features. The first device the group has created is a "diffraction-based" biosensor that can be configured to identify a variety of different organic molecules, including DNA, proteins and viruses. The researchers envision a wide range of applications including drug delivery, chemical and biological sensors, solar cells, and battery electrodes.
Duane Sharrock

As Hurricanes Approach, the Robotic Storm Chasers of the Future Are Ready | Popular Sci... - 0 views

  • Authorities like NOAA gather storm data from a few different sources--from aircraft circling the weather system from tens of thousands of feet, from stationary weather buoys scattered throughout the Gulf of Mexico, from Earth-orbiting satellites--giving scientists a great view of the area around the storm.
  • “Currently there are only two or three ways to get this kind of data,” Dr. Alan Leonardi, deputy director of NOAA’s Atlantic Oceanographic and Meteorological Laboratory, says. “First, you can have a storm serendipitously traverse over a buoy that happens to already be in the water, and that doesn’t happen as frequently as some might believe. Another would be to position a ship out there to collect this data, but that creates a dangerous situation for any crew that might be aboard the ship, so we’re not going to do that. The third--and we have done this--is to deploy instruments from aircraft in front of a storm that can collect data as the storm passes. We then go back in a ship and pick up those buoys--if they survive and don’t end up sinking.”
  • NOAA’s two robotic platforms are being developed independently of one another, yet their roles dovetail neatly. The Liquid Robotics Wave Glider platform is designed as a kind of storm monitoring sentry--like a weather buoy, but one that researchers can move at will. Wave Gliders harvest their propulsive energy from ocean waves themselves and power their onboard electronics with solar energy. This means they are not very fast--too slow to actually chase a storm in most cases--but they can remain at sea for months on end, waiting and watching.
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  • the agency already has one Wave Glider in the water north of Puerto Rico as a test-bed for the dozens NOAA hopes will follow. Isaac tracked south of Puerto Rico and missed the prototype, but the robot did manage to capture data from some intense weather along the outer bands of the system--the first of what NOAA hopes will be a new wealth of hurricane data produced by its robotic fleet.
  • the eyewall--the ring of powerful thunderheads that encircle the eye of the storm.
  • With an operational life of ten days, EMILY can be dropped into the water ahead of a storm, navigate its way into the very center, and remain there, tracking the storm as it moves while streaming data all along the way.
  • Better hurricane prediction translates directly to lowered economic losses, better mitigation of property damage, and--as it goes without saying on the eve of Katrina’s anniversary--lives saved.
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    As the 2012 hurricane season reaches full tilt, researchers at NOAA are hard at work hacking two different maritime robots that the agency hopes will become critical storm forecasting tools of the future. The first, Liquid Robotics' Wave Glider, is envisioned as a persistent surveillance platform, an army of mobile monitoring stations that will remain at sea for the duration of a hurricane season, waiting to swarm into the path of a developing storm. The second--Hydronalix's Emergency Integrated Life Saving Lanyard, or EMILY (a 2010 PopSci Best of What's New award winner)--will be capable of tracking the storm itself for days at a time, streaming continuous data directly from the center of the storm to researchers ashore.
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