Wednesday, May 28, 2014

Screwy-looking wind turbine makes little noise and a big claim

The Liam F1 Urban Wind Turbine is said to be considerably more efficient than most convent...

The Liam F1 Urban Wind Turbine is said to be considerably more efficient than most conventional turbines

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Although it's getting increasingly common to see solar panels on the roofs of homes, household wind turbines are still a fairly rare sight. If Rotterdam-based tech firm The Archimedes has its way, however, that will soon change. Today the company officially introduced its Liam F1 Urban Wind Turbine, which is said to have an energy yield that is "80 percent of the maximum that is theoretically feasible." That's quite the assertion, given that most conventional wind turbines average around 25 to 50 percent.

The 75-kg (165-lb) 1.5-meter (5-ft)-wide Liam obviously doesn't look much like a typical turbine. It draws on the form of the nautilus shell, and the screw pump invented by ancient Greek mathematician Archimedes of Syracuse.

That form factor reportedly results in minimal mechanical resistance, allowing it to spin very freely and to operate quietly – blade noise is one of the common complaints regarding rooftop wind turbines. Additionally, the design is claimed to keep it always pointing into the wind for maximum yield.

It's based on the form of the Nautilus shell and the screw pump invented by ancient Greek ...

Along with its claim of being able to achieve 80 percent of Betz' limit, The Archimedes adds that "The Liam F1 generates an average of 1,500 kilowatt-hours of energy [per year] at a wind-speed of 5 m/s [16.4 ft/s], which resembles half of the power consumption of a common household." Needless to say, it will be interesting to see what independent testing reveals. The company states that it has tested the Liam "over 50 times" to confirm the figures, and has already sold 7,000 of the turbines in 14 countries.

That said, the Liam F1 Urban Wind Turbine should be officially available as of July 1st. Although no price was given in today's announcement, a previous posting on the company website puts it at €3,999 (about US$5,450).

Monday, May 26, 2014

Structural supercapacitors could make batteries and power cords obsolete

Sunday, May 11, 2014

Flexible supercapacitor raises bar for volumetric energy density

Scientists have taken a large step toward making a fiber-like energy storage device that can be woven into clothing and power wearable medical monitors, communications equipment or other small electronics.

Thursday, May 8, 2014

Solar-Powered Air Conditioning

Tesla Logged $713 Million In Revenue In Q1

Tesla Logged $713 Million In Revenue In Q1 and Built 7,535 Cars

from the numbers-are-in dept.
cartechboy (2660665) writesTesla just announced its first-quarter earnings and the numbers are interesting. It logged revenue of $713 million on deliveries of 6,457 Model S electric cars. It's worth noting that's basically the number of vehicles it said it would sell in the quarter, but that number is slightly down from the prior quarter. It built a total of 7,535 Model S cars in the quarter as it built inventory as shipments began to China where sales just started last month. Net orders in North America grew 10 percent, and production for the second quarter is expected to increase to 8,500-9,000 Model S cars. Tesla expects to deliver 35,000 cars during the 2014 calendar year. Musk told analysts that China's enthusiastic and that government support is crucial. The Model X is delayed until spring of 2015 with production-design prototypes being ready in the fourth quarter. Tesla hopes to possibly break ground as early as next month on its gigafactory, though the location has yet to be announced. Of course, the stock market is already reacting to these numbers and is currently down nearly 3 percent in after hours trading.

Saturday, May 3, 2014

Water used by power plants

"Solar" jet fuel created from water and carbon dioxide

In a move that could help address our insatiable thirst for fuel while at the same time help cut CO2 emissions, scientists with the SOLAR-JET (Solar chemical reactor demonstration and Optimization for Long-term Availability of Renewable Jet fuel) project have recently shown that through a multi-step process, concentrated sunlight can be used to convert carbon dioxide into kerosene, which can then be used as jet fuel.
"Increasing environmental and supply security issues are leading the aviation sector to seek alternative fuels which can be used interchangeably with today’s jet fuel, so-called drop-in solutions," says Dr. Andreas Sizmann, the project coordinator at Bauhaus Luftfahrt. "With this first-ever proof-of-concept for 'solar' kerosene, the SOLAR-JET project has made a major step towards truly sustainable fuels with virtually unlimited feedstocks in the future."

Continent’s Tallest Approved Structure to Produce Solar-Wind Energy Hybrid at U.S.-Mexican Border

This thing is almost designed to discredit green energy.  Spraying fresh clean water in a dessert state where clean water is at a premium is just stupid.

This project will burn 1.5 billion dollars of public money building a massive building only to create water shortages.

Just where is this water going to come from?  Green projects need to generate water and power, not consume them.

If they could do this with sea water, great, but this is not the case.

“A series of pumps deliver water to the Tower’s injection system at the top where a fine mist is cast across the entire opening. The water introduced by the injection system then evaporates and is absorbed by hot dry air which has been heated by the solar rays of the sun. As a result, the air becomes cooler, denser and heavier than the outside warmer air, and falls through the cylinder at speeds up to and in excess of 50 mph. This air is then diverted into wind tunnels surrounding the base of the Tower where turbines inside the tunnels power generators to produce electricity.

Thursday, May 1, 2014

Large-area luminescent solar concentrators based on ‘Stokes-shift-engineered’ nanocrystals in a mass-polymerized PMMA matrix

Luminescent solar concentrators are cost-effective complements to semiconductor photovoltaics that can boost the output of solar cells and allow for the integration of photovoltaic-active architectural elements into buildings (for example, photovoltaic windows). Colloidal quantum dots are attractive for use in luminescent solar concentrators, but their small Stokes shift results in reabsorption losses that hinder the realization of large-area devices. Here, we use ‘Stokes-shift-engineered’ CdSe/CdS quantum dots with giant shells (giant quantum dots) to realize luminescent solar concentrators without reabsorption losses for device dimensions up to tens of centimetres. Monte-Carlo simulations show a 100-fold increase in efficiency using giant quantum dots compared with core-only nanocrystals. We demonstrate the feasibility of this approach by using high-optical-quality quantum dot–polymethylmethacrylate nanocomposites fabricated using a modified industrial method that preserves the light-emitting properties of giant quantum dots upon incorporation into the polymer. Study of these luminescent solar concentrators yields optical efficiencies >10% and an effective concentration factor of 4.4. These results demonstrate the significant promise of Stokes-shift-engineered quantum dots for large-area luminescent solar concentrators.

At a glance


  1. QD-LSC concept and electronic structure of thick-shell CdSe/CdS g-QDs.
    Figure 1
  2. Monte-Carlo ray-tracing simulations.
    Figure 2
  3. Optical properties of QD-PMMA nanocomposites.
    Figure 3
  4. Large-area LSC based on Stokes-shift-engineered QDs.
    Figure 4

Breaking up water: Controlling molecular vibrations to produce hydrogen

Breaking up water: Controlling molecular vibrations to produce hydrogen

May 1, 2014
Ecole Polytechnique Fédérale de Lausanne
Converting methane into hydrogen is crucial for clean energy and agriculture. This reaction requires water and a catalyst. Scientists have now used a novel laser approach to control specific vibrations of a water molecule, which can affect the efficiency of the reaction.

Natural gas (methane) can be converted into hydrogen (H2), which is used in clean energy, synthetic fertilizers, and many other chemicals. The reaction requires water and a nickel catalyst. Methane and water molecules attach on the catalyst's surface, where they dissociate into their atomic components. These then recombine to form different compounds like H2 and CO. Previous research has focused mainly on understanding how methane dissociates, but experimental constraints have limited research into water dissociation. Publishing inScience, EPFL scientists have used lasers to determine for the first time how specific vibrations in a water molecule affect its ability to dissociate. The experimental results were used to optimize theoretical models for water dissociation (University of New Mexico), which can impact the design of future catalysts.
Methane is widely used on an industrial scale to produce hydrogen, which is used as a clean fuel and as raw material to produce ammonia used for synthetic fertilizers. The process used is referred to as 'steam-reforming' because it involves methane gas reacting with water steam. This reaction requires a metal catalyst that allows the molecules to dissociate and recombine efficiently. But while the details of methane dissociation have been studied for over a decade, the way water molecules separate has remained elusive.
Fine-tuning vibrations with lasers
The team of Rainer Beck at EPFL, have shown that water dissociation depends strongly on the internal vibrations between its hydrogen and oxygen atoms. In a molecule, the atoms are not static but instead may vibrate in different ways. In a water molecule, the two oxygen atoms can vibrate like a scissor ("scissoring"), or can stretch back and forth either together ("symmetrical stretching") or in turns ("asymmetrical stretching"). "These 'stretches' between the oxygen and the hydrogen atoms play a big role in how well or poorly the water molecule can dissociate on a catalyst," says Beck.
Controlling different types of vibrations is the key to understanding a water molecule's ability to dissociate under mild conditions. Employing nickel as a catalyst -- commonly used in steam reformation -- the team used lasers to precisely control how water molecules are being excited. "If you heat up the system with e.g. a flame, you excite all the degrees of freedom at the same time," explains Beck. "You also increase its kinetic energy, so all the water molecules hit the nickel surface at higher speeds, but you have no control over the individual vibrations of the atoms. With a laser, we can selectively excite one type of vibration, which allows us to measure one energy state at a time."
The data showed that the degree of stretching vibrations between the hydrogen and oxygen atoms in a water molecule determines its ability to dissociate react on the catalyst. This happens because the laser adds energy to the water molecules, increasing vibrations to the point where they break up on the catalyst's surface. This point is called a 'transition state', where the water molecules are ready to react. "Ideally, we want to deform the molecules before the hit the surface, in a way that we have biased the structure towards the transition state," says Beck. "This is why laser-selected vibrations are more efficient that just heating up the entire system: we are putting the energy where it needs to be to break the water molecule's bonds."
From experiment to theory
The unprecedented ability to excite specific types of vibrations allowed theoreticians at the University of New Mexico to calculate all the forces between the atoms and the nickel catalyst surface, and simulate what happens when the water molecule hits the catalyst surface with each type of vibration. Without these experimental measurements, such calculations would lack accuracy.
"With our data, the theoreticians can directly compare their model to the experimental data one vibration type at a time, which is far more accurate," says Beck. "This allows for the optimization of dissociation models that can then better predict how other molecules than water or methane will react on a given surface. Our state-resolved experiments are meant to guide the development of predictive theory."
This optimization of theoretical models can also lead to the faster and more efficient development of catalysts for a range of industrial and commercial chemical reactions. As Beck explains: "You can use a computer model to e.g. vary the spacing of the atoms of the catalyst or change the structure of its surface. This is a cheaper or more efficient way to find a good catalyst, rather than having to do trial-and-error experiments. But in order to trust theoretical model, we need this data to test them against."

Story Source:
The above story is based on materials provided by Ecole Polytechnique Fédérale de LausanneNote: Materials may be edited for content and length.

Journal Reference:
  1. P. M. Hundt, B. Jiang, M. E. van Reijzen, H. Guo, R. D. Beck. Vibrationally Promoted Dissociation of Water on Ni(111)Science, 2014; 344 (6183): 504 DOI:10.1126/science.1251277