Wireless energy transfer

New research is bringing energy transfer into the wireless world. Soon, a central hub could be charging your batteries, laptop, televisions, electric cars, right through the air.

Over the past few years, a number of companies have been racing to put wireless energy on the market. In 2007, researchers at MIT revealed a project that powered a light bulb remotely. The physicist and project leader Marin Soljacic (winner of a MacArthur “genius grant” Fellowship) went on to found the start-up WiTricity.

In the 2007 expeiment they powered a 60W light bulb across a room. At the Nikkei electronics conference in Tokyo in October 2009, they were able to power a 1,000-watt klieg light from across the room. WiTricity’s record so far is 3,000 watts – enough to fully charge an electric car, so long as it’s in the same room (or garage).

The basic underlying principle for transmitting power wirelessly goes back more than a century to the work of Nikola Tesla and other pioneers of electricity, but the MIT team invented a way of making the process far more efficient and practical.

The system works by creating a strong electromagnetic resonance between the sending and receiving coils – similar to the way a tuning fork can start vibrating when exposed to a sound of exactly the right frequency, or the way a radio antenna can be tuned to just the frequency of a single station out of the hundreds that are simultaneously broadcasting their signals. In this case, the magnetic resonance between the two coils is unaffected by objects in between the coils, and by the same token objects between the coils – including people – are not affected by the magnetic fields.

Several concerns, even initially from WiTricity CEO Eric Giller, have been raised about the potential health risks as magnetism from MRI machines can disable pacemakers. But, MRI magnetism is about 10,000 stronger than that in WiTricity and the Institute of Physics in London has found WiTricity’s magnetic field “has no detrimental effects on the human body.”

Already, companies focused on a special application of wireless electricity have broken into the retail market with force. Powermat, and soon WiPower, provide “wireless charging” stations for home electronics. Instead of plugging in your mobile phone or handheld video game, you just strap a receiver on it, and place it on a charging mat. This “drop and charge” innovation is set to make a big impact in retail sales (Powermat sold more than 750,000 products in just two months) and could be the first step to the wireless electricity revolution that changes the way we power our lives.

Gieler of WiTricity mentioned at the TED 2009 conference that the technology can conceivably still get a lot better. We could use a similar method of coupling to power objects from a meter away or farther. At that distance, we could power electric cars while they were still on the road, or create homes without plugs.

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Small, clean, green machines

MIT CityCarWhile mass transportation systems such as trains or busses are hailed as the solution for urban mobility, there is often the problem with the last mile. MIT Media Lab (with support from GM) has developed a small car, the CityCar, specifically to be used in an urban context and for car sharing.The 2-seater cars are fully electric and also stackable. They work a bit like shopping carts in when the behind car touches a parked one in front, the front car lifts its body enabling stacking. When you want to drive off again, you merely touch a button and the front car disengages and moves slightly forward. The idea is that anyone uses any car.

A further feature is that the cars are capable of 360° steering, making parking a dream.

Because the cars are part of a single, computerized network, their placement can be coordinated to reduce traffic congestion or make transportation options available at peak times and places. Rental charges could fluctuate to encourage alternate routes. Commuters could keep track of where and when cars and parking spaces are available in real time, using cellphones or other hand-held devices to track the cheapest or the most convenient car, spot, or route.

Ryan Chin, one of team working on this project, said: “When you think of this, you shouldn’t think of a car. You should think of it as a new personal and sustainable mobility system and service. This is a clean and green machine.”

MIT has submitted a proposal to a government in Asia that is interested in building a network of these cars in one of their cities. The CityCar was part of the plan submitted by MIT that also recently won the 2009 Buckminster Fuller Challenge.

Lower cost Maglev transport solution

Engineers at LaunchPoint Technologies have been working with Applied Levitation and Fasttransit Inc, to develop a completely new, revolutionary mode of maglev transportation.

Using Applied Levitation’s no-contact Stabilized Permanent Magnet (“SPM”) levitation system it will permit incremental upgrade of current rail and subway systems. By installing SPM guideways on the same ties as existing tracks, with one maglev rail outside each of the existing steel rails and a motor rail down the center, SPM maglev vehicles can operate simultaneously with standard rail and subway vehicles. As a result, existing rail and subway cars can remain in operation while being gradually replaced with new maglev vehicles that cost less and perform far better. This capability avoids the need to completely overhaul current infrastructure at tremendous cost.

The FASTRANSIT system is a packet-switching transportation network that uses permanent magnetic levitation and linear motors for instant switching and direct routing on an ultra-high capacity network. The system can be used for mass transit, freight transport or personal rapid transit.
Some of the proposed benefits of this system are:

• Low capital cost–SPM maglev guideways can be built, mile for mile, for about the same cost as one lane of freeway with twenty times the carrying capacity.
• Easily integrated–Existing rail and subway systems can be easily retrofitted with SPM maglev capabilities, enabling incremental upgrades of an aging infrastructure.
• Fast switching–SPM maglev technology uses instant magnetic switching with no moving parts which enables more efficient routing of computer-controlled maglev vehicles.
• Network capability (Mag-Net^TM)–With SPM maglev technology and instant magnetic switching, transportation networks can be developed to route traffic in much the same way as information is routed over the internet.
• Highly scalable–SPM maglev technology can be used with smaller, lighter vehicles for more efficient passenger transportation, or with bigger, heavier vehicles for the transport of freight.

 The firms have already tested the system on a scale and a short indoor track, and is now planning a quarter mile outdoor track.

Maglev rails have been built and tested since about 1980 and a few high speed maglev railways are in operation, most famously the one between downtown Shanghai and Pudong International Airport. The California University of Pennsylvania is currently investigating an urban maglev system (not with SPM technology) for its campus.

Ice Energy to lower peak demand

The Southern California Public Power Authority and Ice Energy are launching a project to shift 53 megawatts of peak-time power consumption to hours of lower demand by deploying units that make and use ice to run air conditioners.Founded seven years ago, Ice Energy developed its Ice Bear Distributed Energy Storage System to work with standard rooftop air conditioning units on small to midsized commercial buildings.

At night, when demand on the grid is low, the Ice Bear goes in to “ice charging” mode, freezes 450 gallons of water and stores it. During the day when the grid reaches peak demand levels, typically between noon and 6 p.m., the Ice Bear goes into “ice cooling” mode. It takes over from the air conditioner’s energy-intensive compressor and cools the hot refrigerant using the ice made the night before. The cooling cycle lasts at least six hours until the ice completely melts, at which point the AC compressor goes back on the job and the ice making and cooling cycles begin again.

Installation for SCPPA will begin in the first half of the year and rolling deployment will take about two years. About 1,500 government, commercial and industrial buildings — retrofits and some new construction — will be involved.

The power authority and the company say that the project will permanently reduce demand peak electricity demand and, when complete, can shift as much as 64 gigawatt hours of on-peak consumption to off-peak times annually. The power authority estimates that the shift can offset enough peak demand to serve the equivalent of 10,000 homes.

The system costs about $2000 per kilowatt of capacity

For utilities, energy storage systems are considered key Smart Grid components because of their capacity to store energy efficiently and dispatch it when and where needed. Ice Energy said they have tested the technology with 20 utilities in the United States and Canada and they are looking forward to other major projects.

Original article: GreenerBuilding staff. 27 January 2010. Read more…

Concentrating solar power with a Stirling engine

In January 2010, Teserra Solar and Stirling Engine Systems showcased the Maricopa Solar plant in Arizona. This is the first commercial project for the SunCatcher concentrating solar power technology designed and manufactured by Stirling Engine Systems.The innovative and highly-efficient SES SunCatcher is a 25-kilowatt solar power system which uses a 38-foot, mirrored parabolic dish combined with an automatic tracking system to collect and focus the sun’s energy onto a Stirling engine to convert the solar thermal energy into grid-quality electricity. Developer Tessera Solar has created a 1.5 megawatt power plant out of 60 SunCatcher solar thermal devices.

SunCatcher has a number of advantages including the highest solar-to-grid electric efficiency, zero water use for power production, a modular and scalable design, low capital cost, and minimal land disturbance. SunCatcher was designed and developed in America, through a public-private partnership with the U.S. Department of Energy. The SunCatchers unveiled at Maricopa Solar were manufactured and assembled in North America, mostly in Michigan by automotive suppliers.

Now that the plant is up, Stirling will be able to compare the results its gets from its Stirling engines from heliostat prototype power plants erected by eSolar in Southern California and BrightSource Energy in Israel as well as parabolic trough systems that have already been commercially deployed. Parabolic companies, BrightSource and eSolar collect solar heat on mirrors and use it to heat fluid. The warmth causes the fluid to expand, which creates pressure that gets exploited to crank a turbine.

The Company has publicly quoted a fully-installed cost for grid-scale plants of $2.8 million per megawatt.

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