Archivio aprile 2010

Home Sensor Startup Snapped Up

Fonte: www.technologyreview.com

Belkin buys Zensi, which makes sensors to track domestic energy and water usage.

By Kate Greene

If you knew how much electricity your plasma television used or how much water your dishwasher drank at different times of day, would you change your habits to conserve more and spend less on utilities? Researchers at the University of Washington, Duke University, and Georgia Tech believe that you might. Several years ago they invented sensors that could track the electricity consumption and water usage throughout an entire building via a single point on each system. In 2008, the researchers founded a company called Zensi to commercialize the technology, and last week, they sold that company to Belkin, an electronics hardware manufacturer.

A line of easy-to-install sensors for homes could be commercially available within the next year, says Shwetak Patel, professor of computer science and engineering at the University of Washington, and co-inventor of Zensi’s sensors. Data from such sensors could lead to itemized utility bills–and customers who are more aware of the energy sinks in their homes, he says.

Right now it’s impossible for a consumer to get an accurate gauge of energy use without deploying numerous expensive sensors. But cost reductions in key technologies have made the concept of watching every device in a home more feasible, says Ivo Steklac, executive vice president of sales and strategy at Tendril, a Boulder, CO-based, energy-monitoring startup. The key technologies are high-speed analog-to-digital conversion devices, digital signal processing algorithms, low-power communications, and ubiquitous Internet access and connectivity, Steklac says.

The concept behind Zensi’s technology is simple: a single sensor is plugged into a wall outlet, where it “listens” to the high-frequency electrical noise produced in the wiring when different devices are turned on. Each electrical device has a signature that is unique to the kind of device it is, its brand, and its location within a house. This information, in turn, reveals its energy consumption. MIT professor Fred Schweppe, and others tested a similar idea more than a decade ago. In the case of plumbing, a sensor is connected to the hose spigot on the side of a house. When a toilet is flushed or a sink is turned on, the sensor detects the characteristic change in pressure.

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Wind Turbines Shed Their Gears

Fonte: www.technologyreview.com

Both Siemens and GE bet on direct-drive generators.

By Peter Fairley

Turbina Siemens

Power ring: This three-megawatt wind turbine uses permanent magnets and a design that makes it significantly lighter than a conventional geared turbine. Credit: Siemens

Wind turbine manufacturers are turning away from the industry-standard gearboxes and generators in a bid to boost the reliability and reduce the cost of wind power.

Siemens, the world’s largest turbine manufacturer by volume, has begun selling a three-megawatt turbine using a so-called direct-drive system that replaces the conventional high-speed generator with a low-speed generator that eliminates the need for a gearbox. And last month, General Electric announced an investment of 340 million euros in manufacturing facilities to build its own four-megawatt direct-drive turbines for offshore wind farms.

Most observers say the industry’s shift to direct-drive is a response to highly publicized gearbox failures. But Henrik Stiesdal, chief technology officer of Siemens’s wind power unit, says that gearbox problems are overblown. He says Siemens is adopting direct-drive as a means of generating more energy at lower cost. “Turbines can be made more competitive through direct-drive,” says Stiesdal.

Siemens’s plans hinge on a new design that reduces the weight of the system’s generator. In conventional wind turbines, the gearbox increases the speed of the wind-driven rotor several hundred fold, which radically reduces the size of the generator required. Direct-drive generators operate at the same speed as the turbine’s blades and must therefore be much bigger–over four meters in diameter for Siemens’s three-megawatt turbine. Yet Siemens claims that the turbine’s entire nacelle weighs just 73 metric tons–12 tons less than that on its less powerful, gear-driven 2.3-megawatt turbines.

Much of the weight reduction comes from the use of permanent magnets in the generators’ rotor–a trick that GE is also using. Conventional turbine generators use electromagnets–copper coils fed with electricity from the generator itself. Henk Polinder, an expert in permanent-magnet generators at Holland’s Delft University of Technology, says that a 15-millimeter-thick segment of permanent magnets can generate the same magnetic field as a 10- to 15-centimeter section of copper coils.

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Solar Energy: Cheaper Solar Concentrator With Fewer Photovoltaic Cells

Fonte: Science Daily

A new solar concentrator design from an electrical engineering Ph.D. student at the University of California, San Diego could lead to solar concentrators that are less expensive and require fewer photovoltaic cells than existing solar concentrators. The graduate student, Jason Karp and his colleagues at the UC San Diego Jacobs School of Engineering presented the new solar concentrator in a paper in the January 2010 issue of the journal Optics Express. While engineers have already developed high-efficiency solar concentrators that incorporate optics to focus the sun hundreds of times and can deliver twice the power of rigid solar panels, the new design offers potential new benefits. Existing solar concentrator systems typically use arrays of individual lenses that focus directly onto independent photovoltaic cells which all need to be aligned and electrically connected. In contrast, the new solar concentrator collects sunlight with thousands of small lenses imprinted on a common sheet. All these lenses couple into a flat “waveguide” which funnels light to a single photovoltaic cell.

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Dissalare l’acqua marina grazie al solare fotovoltaico a concentrazione e alle nanomembrane

Fonte:  IBM

Well-defined Nanostructured Membranes - IBMIBM e King Abdulaziz City for Science and Technology (KACST), l’organizzazione nazionale di ricerca e sviluppo dell’Arabia Saudita, hanno intrapreso una collaborazione di ricerca finalizzata a creare un impianto di dissalazione dell’acqua basato su una combinazione di due tecnologie innovative ed in grado di offrire una soluzione alla crescente domanda di acqua potabile da parte della popolazione saudita. Nella città di Al Khafji sarà infatti costruito prossimamente un nuovo impianto di dissalazione ad alta efficienza energetica, con una capacità di produzione prevista di 30.000 metri cubi al giorno ed idoneo a  servire 100.000 persone. Il KACST prevede di alimentare l’impianto con la tecnologia UHCPV (Ultra-High Concentrator Photovoltaic), sviluppata insieme ad IBM, utilizzando un sistema fotovoltaico (CPV) ad una concentrazione superiore a 1.500 soli. All’interno dell’impianto, inoltre, il processo di dissalazione sarà basato su un’innovativa tecnologia a nanomembrana in grado di filtrare i sali e le tossine potenzialmente nocive presenti nell’acqua, utilizzando minore energia rispetto ad altre forme di depurazione.

Allo stato attuale i metodi più comunemente impiegati per la dissalazione dell’acqua marina sono la tecnologia termica (distillazione seguita da condensazione) e l’osmosi inversa, ma presentano entrambi un costo troppo elevato per essere applicato su larga scala. Nella osmosi inversa, in particolare, l’elevato costo è dovuto soprattutto a problemi di natura tecnica che pregiudicano il buon funzionamento delle membrane polimeriche comunemente utilizzate nel processo. La ricerca congiunta KACST e IBM è incentrata sul miglioramento delle membrane attraverso la modifica delle proprietà dei polimeri su nanoscala. Grazie alla combinazione offerta dall’elevato apporto energetico fornito dalla tecnologia solare a concentrazione e dalle proprietà della nuova nanomembrana, sarà possibile migliorare l’efficienza energetica del processo e ridurre significativamente il costo della dissalazione dell’acqua marina.

Trasformare l’acqua salata in acqua dolce in modo efficace in termini di costi ed efficiente in termini di energia offre un enorme potenziale per affrontare la crescita della domanda mondiale di acqua pulita. Attualmente nel nostro pianeta una persona ogni cinque non ha ancora accesso all’acqua potabile e occorre trovare presto una soluzione per far fronte a questa crescente domanda.  Utilizzando queste nuove tecnologie, IBM e KACST si pongono l’obiettivo di realizzare sistemi di desalinizzazione implementabili a breve sia in tutta l’Arabia Saudita che a livello mondiale.

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Electric drive concepts for the cars of the future

Fonte: www.fraunhofer.de

The prospects look good that wheel hub motors will successfully become the accepted drive concept for electric vehicles. Fraunhofer researchers are engineering these motors, which are integrated into the car’s wheels. Scientists are testing these and several other components on the »Frecc0«, their demonstration vehicle. Working jointly in a multidisciplinary cooperation of 33 Fraunhofer institutes, they are paving the way for future technologies in all areas of electromobility. The »Fraunhofer System Research for Electromobility« makes its debut appearance at this year’s Hannover Messe (April 19 – 23, Hall 2, Booth D22).

The Fraunhofer wheel hub motor on the "Frecc0" demo vehicle.

The Fraunhofer wheel hub motor on the "Frecc0" demo vehicle.

In order to make electric cars a part of everyday life, new vehicle designs and parts are needed. Take wheel hub motors, for instance. One of the advantages of wheel hub motors is that manufacturers can dispense with the conventional engine bay – the space under the »hood« or »bonnet« – since the motors are attached directly to the wheels of the vehicle. This opens up a wealth of opportunities for car designers when drafting the layout of the vehicle. Additional advantages: By dispensing with the transmission and differential, the mechanical transmission elements suffer no losses or wear and tear. Moreover, the direct drive on each individual wheel may improve the drive dynamic and drive safety.

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A Bright Redesign for LED Lights

Fonte: www.technologyreview.com

Illumitex’s new optical design makes LEDs brighter and more energy efficient.

By Erika Jonietz

Illumitex, an LED-manufacturing company based in Austin, TX, launched its first product line earlier this month. The startup’s first LEDs are designed for general-purpose lighting and emit a uniform, narrow beam of white light that is almost two times brighter than any white LED on the market. The founders, all of whom have backgrounds in optics rather than solid-state lighting, achieved this by redesigning the package around the semiconductor chip that actually converts electricity into light.

Illumitex's LEDs have a unique flat, square package that allows engineers to extract more light from the semiconductor chips at the heart of the diodes. Courtesy Illumitex

Illumitex's LEDs have a unique flat, square package that allows engineers to extract more light from the semiconductor chips at the heart of the diodes. Courtesy Illumitex

Traditionally, LED manufacturers have enclosed the chips inside a dome in order to control the light output. Illumitex’s LEDs ship in a flat, square package that eliminates the cost and energy efficiency issues that come from using secondary optical lenses and reflectors. Cofounder and chief scientist Dung Tien Duong, who is the company’s primary inventor, won’t say much about how the unique package allows Illumitex engineers to extract more light from the LED dies, but he does say it takes “intuitive” advantage of physics principles. “If the chip is square, the light beam should be square,” he says. While the company is mum on the exact physics behind its achievements (patents are still pending), it has published data sheets for both its 16-die and 4-die LEDs, including some data verified by third-party testing companies.

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Frigoriferi intelligenti per gestire la domanda di elettricità

Fonte: QualEnergia

[..] È una prova di rete intelligente quella che sta partendo nel Regno Unito grazie all’azienda specializzata in tecnologie per la gestione della domanda elettrica RLtec, l’utility RWE-Npower, Indesit e alcune grandi catene di supermercati. Tutto ruota attorno al sistema di gestione dinamica della domanda che RLtec ha applicato ai frigoriferi: un dispositivo che fa sì che la macchina moduli i consumi in relazione  alla domanda di elettricità complessiva della rete.

Il frigo, che comunica con il sistema elettrico in tempo reale, preleva più elettricità quando nella rete ce n’è in sovrappiù e riduce o azzera i consumi durante i picchi, cioè quando la domanda generale è più alta.  Il dispositivo non compromette le prestazioni del frigorifero, ma da’ un grande vantaggio al sistema elettrico in termini di efficienza. L’elettrodomestico diventa così infatti una sorta di buffer o di batteria della rete: un elemento sempre più necessario in un sistema elettrico caratterizzato dal ruolo crescente  di fonti dalla produzione aleatoria e non programmabile, come l’eolico.[..] Per ora, specifica RLtec, non è economicamente conveniente montare il sistema sui frigoriferi esistenti, ma avrebbe senso adottare i frigoriferi intelligenti presso i grossi consumatori. In atto c’è già un progetto pilota, realizzato assieme ad Indesit, per distribuire 300 frigoriferi intelligenti ad altrettanti utenti della rete e monitorarne i consumi. Ora si stanno prendendo accordi con alcune grandi catene di supermercati per allargare il progetto e far salire a 3000 il numero dei “frigoriferi anti-picco”. Dalla parte del consumatore, infatti, i dispositivi non comportano cali delle prestazioni o aumenti in bolletta, anzi, l’utente potrebbe ottenere dai fornitori tariffe elettriche scontate in cambio del permesso a ridurre la fornitura durante i momenti di picco.

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Nanocristalli producono idrogeno utilizzando i rumori ambientali

Fonte: Rinnovabili.it

Il piezoelettrico ancora una volta al servizio della ricerca energetica. Scienziati statunitensi mettono a punto un processo per utilizzare i rumori ambientali nella sintesi di idrogeno

[..] Se la tecnologia per sfruttare il vettore energetico idrogeno può contare su risultati consolidati, diverso è però il discorso per quella produttiva. Il processo di sintesi richiede energia e come ottenerla senza che la produzione del vettore abbia costi energetici maggiori rispetto a quelli riottenibili è ovviamente la questione principe. Molte delle indagini stanno vertendo sulle rinnovabili per trasformare l’idrogeno in una sorta di sistema di stoccaggio dell’energia. In questo filone di indagine rientra anche il lavoro condotto dall’University of Wisconsin-Madison, scopritore di un nuovo processo per idrolizzare i legami chimici delle molecole d’acqua impiegando rumori ambientali. Gli scienziati hanno coltivato dei nanocristalli di ossido di zinco e titanato di bario. Posti in acqua hanno poi stimolato le molecole con vibrazioni ultrasoniche, accorgendosi che le strutture nanoscopiche si flettevano fungendo da catalizzatori per la reazione di rottura delle molecole d’acqua in idrogeno e ossigeno. Finora i ricercatori hanno raggiunto un’efficienza del 18 per cento con i nanocristalli, una percentuale più alta rispetto alle altre fonti energetiche sperimentali. Huifang Xu, capo progetto, ha spiegato: “Poichè siamo in grado di regolare le dimensioni delle fibre e delle piastre, possiamo utilizzare anche piccole quantità di rumore – come una vibrazione o l’acqua che scorre – per piegare i nano dispositivi”. [..]

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Creating a Portable X-Ray Machine

Fonte: www.technologyreview.com

A California company is developing a compact, flat-panel source of x-rays.

By Katherine Bourzac

Electric point: This point, carved into a pyroelectric crystal, emits electrons when the material is heated. A flat-panel x-ray source uses an array of such points to make a more uniform field for medical imaging. Credit: Gil Travish

Electric point: This point, carved into a pyroelectric crystal, emits electrons when the material is heated. A flat-panel x-ray source uses an array of such points to make a more uniform field for medical imaging. Credit: Gil Travish

A startup company is developing a flat-panel source of x-rays that could help make the imaging technique portable. The company’s panels are made using techniques commonplace in the semiconductor industry and would be combined with flat-panel image sensors to make a briefcase-sized x-ray machine powered by a laptop battery. Such a system might be used in the field by the military or instead of bulky bedside systems used in hospital intensive-care units. Early research also suggests it might expose patients to less radiation.

The company behind the x-ray source, Radius Health, was spun out of the University of California, Los Angeles last year. It is developing a commercial version of a flat-panel x-ray source developed by physicists at the university. The company will make its first complete x-ray imager in three to four months and says it will have a full-scale prototype in a year.

The x-ray machines used in hospitals today employ a high-energy source of the radiation. A tungsten filament at one end of a long vacuum tube emits electrons when heated and those accelerate down the tube until they hit a metal electrode, causing it to produce x-rays.

Many groups are working to develop more compact and robust x-ray sources, says Dieter Enzmann, chair of radiological sciences at the University of California, Los Angeles Health System. Enzmann was not involved with the development of the new x-ray source but serves on Radius Health’s advisory board.

A key advantage of Radius Health’s system is that it uses an array of emitters, rather than a single source. “There is some potential to reduce the x-ray dose if you can control hundreds or thousands of x-ray sources independently,” says Enzmann. This lower dose would be especially attractive for pediatric imaging, Enzmann says, adding “if you have a portable, thin design that generates good images, it could be used both in the field and within the hospital.”

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