Formula 1 Cars and Mazda Recover Waste Energy

by Dean Sigler on 01/25/2012

David Bettencourt, a criminal defense attorney and aviation lawyer in Hawaii, is a follower of Formula 1 racing and energy-efficient systems.  He filed a brief with your editor on the following.

Kinetic Energy Recovery Systems (KERS) were a relatively new thing in Formula 1 racing in 2009, had significant development problems and were banned in 2010.   Reinstated in 2011, the systems recover the kinetic energy present in the waste heat created by the brakes and exhausts. The energy is then stored in a battery or a light, extremely high-speed flywheel, converted into power and can then deliver a maximum of 60 kilowatts (80 horsepower), which can be called upon by the driver to boost acceleration for up to 6.6 seconds per lap.

Williams is a major Formula 1 constructor and developer.  Sam Michael, Williams technical director, explains.  “The rules have changed since KERS was last used in F1.  Re-fuelling is no longer permitted, so the packaging is different now. We have packaged our KERS system entirely inside the car’s survival cell, below the fuel tank, because we didn’t want to compromise any of the sidepod area for aerodynamics. The car is longer than last year as a result, but the advantages of doing that outweigh the negatives. Assuming you’re on the weight limit, there is no downside to KERS; it’s worth 0.3s and it gives you a better start.”

KERS systems will be used by a great many  competitors in the 2012 season and are being developed by a consortium  including Ricardo, CTG, JCB, Land Rover, SKF, Torotrak and Williams Hybrid Power.

The potential  for commercial and private vehicles is enormous, since buses and cars will not  be limited to six-second power bursts.  The price, noted below, is a hopeful surprise, and one which, if the systems are successful in  providing the projected fuel savings, would enable short pay-back on a modest investment.  Imagine one of these light flywheels adding to takeoff power on a light electric airplane, then collecting waste energy in flight to recharge onboard batteries.

According to Ricardo Engineering, “The project aims to demonstrate the potential of using high-speed flywheel technologies – including both (Ricardo’s) Kinergy and competitor systems – in delivering hybrid systems with the potential for 30 percent fuel savings (and equivalent reductions in CO2 emissions) at an on-cost of below £1000 ($1,500), thus enabling the mass-market uptake of hybrid vehicles in price-sensitive vehicle applications.

Ricardo’s Kinergy flywheel is “The subject of nine Ricardo patent families in application… [representing] an advance in mechanical energy storage technology based on a high-speed carbon fibre flywheel operating within a hermetically sealed vacuum chamber at speeds of up to 60,000 [revolutions per minute].  But unlike current devices in which energy is imported and exported via a drive shaft operating at flywheel speed, Kinergy transfers torque directly through its containment wall using a magnetic gearing and coupling system.”

Initially developed for a “Flybus” project, the prototype flywheel could store up to 960  kilaJoules of energy – which translated into a 6.6 second burst, would give a city bus an extra 145 kilowatts (194 horsepower) of energy to win the stoplight Gran Prix.  Again, consider the mileage or power benefits for domestic use unshackled by tight racing regulations.

In a further domestic approach that might find other applications, including racing, Mazda has announced a capacitor-based KERS system that stores regenerative energy derived from braking.

Mazda says, “The Intelligent Energy Loop (i-ELOOP) system will begin to appear on production Mazdas in 2012 and is claimed to reduce real-world fuel consumption by as much as 10 percent.  Capacitors offer numerous advantages over batteries for short-term energy storage… they can be charged and discharged very rapidly, they store large amounts of energy, they are light and they resist deterioration through prolonged use.  The electricity saved will be used to power the climate control system, the audio and other electrical loads.”

According to their press release, “Mazda examined automobile accelerating and decelerating mechanisms, and developed a highly efficient regenerative braking system that rapidlyrecovers a large amount of electricity every time the vehicle decelerates.  Unlike hybrids, Mazda’s system also avoids the need for a dedicated electric motor and battery.

“’i-ELOOP’ features a new 12-25V variable voltage alternator, a low-resistance electric double layer capacitor and a DC/DC converter. ‘i-ELOOP’ starts to recover kinetic energy the moment the driver lifts off the accelerator pedal and the vehicle begins to decelerate. The variable voltage alternator generates electricity at up to 25V for maximum efficiency before sending it to the Electric Double Layer Capacitor (EDLC) for storage. The capacitor, which has been specially developed for use in a vehicle, can be fully charged in seconds. The DC/DC converter steps down the electricity from 25V to 12V before it is distributed directly to the vehicle’s electrical components. The system also charges the vehicle battery as necessary.”

These developments indicate an increasing and appropriately accelerating interest and determination to reach high efficiencies and reduce fuel use – always a good thing.

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Charging Your EV on the Move

by Dean Sigler on 01/17/2012

Qualcomm is best known for its quirkily-named Wi-Fi and other wireless communications technologies; ETHOS®, Haystack®, and Gobi®, for starters.  Relatively low-powered, they allow notebooks and smartphones access to broadband connectedness.

Qualcomm's HaloIPT inductive charging system

Qualcomm has now expanded its reach, and its power, to inductive charging for electric vehicles.  Its wireless electric vehicle charging (WEVC) technology, HaloIPT will first allow wireless recharging of electric vehicles which park over a “sweet spot” that has the capability of sending power “over an air gap of hundreds of millimeters while still maintaining high-energy transfer electricity,” according to the company.

PCWorld reports that Halo’s inductive “WEVC can transfer up to 3.5 kilowatts of power at greater than 90 percent efficiency – that’s as good as, or even better, than wired charging.  Instead of plugging in the EV to a charging station, the car will have a charging plate attached to its chassis.  A charging mat, placed above or below the pavement, magnetically transfers power to the vehicle through the gap between them.  Qualcomm explains that the car doesn’t even need to be precisely parked over the mat, a great deal of tolerance being built into the system.

3.5 kilowatts will have some leakage current, making it a possible danger to those with electronic medical devices or implants.  Not to worry, according to its inventors, since the technology will actually have a claimed leakage lower than that for current-carrying plug-in cables.

Initial plans from HaloIPT include low-power mats for slow charging at home, higher-powered units for faster charges in public and workplace parking areas, stackable units for taxi ranks and buses, and, “Ultimately, we will develop dynamic charging, which will enable your electric car to be powered on the move.  This is the most effective way to enable long-range electric car transport.”

Halo WEVC will start a two-year trial of the prototype system in London, using about 50 cars.  If that trial succeeds, the technology will go to the consumer market, where “Qualcomm initially plans to license the technology to automakers, who will integrate the charging plate on the bottom of electric vehicles and include a portable charging mat.”

If dynamic charging becomes a reality, EVs would have essentially unlimited range as long as they were driven on powered streets and highways.

This might even have implications for aviation applications.  Consider a runway with power mats down the centerline.  An airplane could augment its takeoff performance up to liftoff, saving precious energy in its batteries for moderately longer-range cruising.  It might be possible to pull regenerative energy from landing aircraft.  Questions arise, however, as to whether the added weight of the system would offset potential benefits.

Inductive Power Technology, as acquired by Qualcomm, is a product of the University of Auckland, New Zealand and its commercialization company Auckland UniServices Ltd.  Qualcomm and Aukland Uniservices have committed to a long-term research and development arrangement to promote continued innovation in the field of wireless charging for electric road vehicles by way of inductive power transfer.

According to the University, “Inductive Power Technology (IPT) was pioneered by Professor John Boys and Associate Professors Grant Covic and Udaya Madawala from the University’s Power Electronics Group.  They have led the world in developing systems to transmit electric power efficiently across air gaps without using wires.”

“’IPT will become the standard technology for electric-powered vehicles.  Vehicles fitted with our technology will be able to charge overnight using electricity generated by renewable sources such as wind. Because there is a low demand for electricity at night, little or no extra installed generating capacity will be required to power our fleet of electric vehicles,’ said Dr. Peter Lee, Chief Executive of UniServices.”

Whether Qualcomm’s adaptation of Halo technology becomes the standard remains to be seen, even though Rolls-Royce uses it for its luxury EV.  Qualcomm has competitors, though, from Mercedes, working with Conductix-Wampfler; Flanders Drive, a Belgian company; to A Better Place, Shai Agassi’s Israeli firm, among others.

Conductix-Wampfler notes the universality of ITP technology.  “Inductive charging has advantages for automobile manufacturers as well. Induction systems avoid the problems inherent with the lack of cable/plug standards. Newly released plug standards from North America, Japan, and Europe are different, causing manufacturers to adapt to many different standards. Using inductive power, on the other hand, can be made international, since the laws of physics are the same everywhere.”

With this complement of organizations and others involved in developing inductive charging systems, we should begin to see the benefits of their efforts in short order.

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We Know It Flies Well, But Does It Look Good?

by Dean Sigler on 01/13/2012

Taja Boscarol, Public Relations Manager for Pipistrel, sends notice that their Taurus Electro G4 is a finalist in the Design Museum’s “Designs of the Year” competition for 2012 in the Transport category.  This will be the second year in a row that an electric airplane has been nominated in the prestigious competition, last year’s win being taken by the Yuneec e430.

The London-based Design Museum’s Design Awards are considered “the Oscars of the design world,” and are given in seven categories: Architecture, Digital, Fashion, Furniture, Graphics and Transport and Product.  Pipistrel’s Green Flight Challenge-winning airplane will be up against a range of transportation-related designs, including:

AUTOLIB’, a car-sharing program developed by SOCIÉTÉ AUTOLIB’ SAS AND Bertrand Delanoë, Mayor of Paris, France with the ambition of reducing car ownership.

A Ferris-wheel-like bike hanger created by Manifesto Architecture of New York, New York.

Manifesto Architecture's bike hanger as it might look in Seoul, South Korea

The Mia electric car, a three-seat van-like vehicle by Murat Guenak and David Wilkie of Mia Voiture Electrique.

The Mia electric in its native setting

A re-design of the emergency ambulance by the Helen Hamlyn Centre for Design and the Vehicle Design Department of the Royal College of Art in London, UK.

The T27 Car  from Gordon Murray Design, Surry, UK.  Murray  is a Formula 1 designer who’s turned his skills to developing what may be “the most efficient car in the world,” according to this site.

The Boeing 787 Dreamliner, by Boeing Aircraft, Illinois, USA.  It only gets 100 passenger miles per gallon, though.

Pipistrel  is up against distinguished competition, and CAFE’s best wishes go with the talented designers who make its form as beautiful as the airplane’s wondrous function.

 

 

 

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Measuring Up To Standards

by Dean Sigler on 01/11/2012

ASTM International, formerly known as the American Society for Testing and Materials, develops “international consensus standards” for many industries, using input from its members in many fields and disciplines.  Their D-7566-11 “Standard Specification for Aviation Turbine Fuel Containing Synthesized Hydrocarbons” governs what can be put into jet and turbo-prop aircraft.  Updated in July 2011, it now allows the use of biologically-derived fuel “without the need for special permissions,” according to SAE International, itself a standards organization, and as reported by Patrick Ponticel.

General Electric's jet engine testing rig

United Airlines was quick to take advantage of the revised standard, using “Solazyme-supplied algae oil that was refined into jet fuel by Honeywell’s UOP division near Houston. The blend used for the November 7, Boeing 737-800 flight was 40-percent Solazyme’s Solajet and 60-percent petroleum-derived commercial jet fuel (Jet-A).”

SAE explains that, “Under the ASTM standard, up to 50-percent bio-derived synthetic blending components can be added to conventional jet fuel. These renewable fuel components, called hydroprocessed esters and fatty acids (HEFA), are identical to hydrocarbons found in jet fuel, but come from vegetable oil-containing feedstocks such as algae, camelina, and jatropha, or from animal fats called tallow.”

Besides producing its algae-based product, Solazyme, a San Francisco-based company, has teamed with Dynamic Fuels to create plant- and animal-based fuel for the U. S. Navy, an early adapter of the technology.  With engine manufacturers such as General Electric and Rolls-Royce approving the use of such fuels after careful review and testing of their merit, the future would seem to be promising for these non-fossil alternatives.

Mike Epstein of GE Aviation notes that “’for some of those companies, it’s a challenge to make a thousand gallons, which is just a beginning point.’  To put things into perspective, he said, the amount of jet fuel consumed annually around the world is about 65 billion gallons.” (And that would only be about 2 percent of the world’s total fuel demand! Editor)

The allure of domestically-produced fuel and its performance are not lost on engine manufacturers.  Following tests on two Embraer engines, Epstein said, “The fuel performed as expected and is consistent with Jet-A.”  A Boeing spokesperson adds that “biofuels have proven to perform even better than conventional jet fuel.”

Following United flight 1403’s successful outing, Solazyme signed letters of intent to supply 20 million gallons of renewable aviation fuel per year to United starting in 2014.

“Today’s historic flight with United marked a significant milestone in the history of aviation, and demonstrated the commercial applicability of our drop-in fuel,” said Jonathan Wolfson, CEO, Solazyme.  “The U.S. Navy has demonstrated the effectiveness of our fuel in multiple vessels over the past year, and we are honored to be working with industry pioneers such as United and Honeywell’s UOP to see this important next step in the commercialization of our renewable fuels.”

Following closely on the United first flight, a December 5 press release cited Dynamic Fuels, LLC, a joint venture between Tyson Foods, Inc. and Syntroleum Corporation, as having been awarded a contract to supply 450,000 gallons of renewable fuels to the Navy.  Solazyme will assist Dynamic Fuels in fulfilling the contract.

“The contract involves supplying the Navy with 100,000 gallons of jet fuel (Hydro-treated Renewable JP- 5 or HRJ-5) and 350,000 gallons of marine distillate fuel (Hydro-Treated Renewable F-76 or HRD-76). The fuel will be used as part of the Navy’s efforts to develop a ‘Green Strike Group’ composed of vessels and ships powered by biofuel.”

Dynamic Fuels and Solazyme have already worked with KLM Royal Dutch Airlines, Finnair, Thomson Airways and Alaska Airlines in supplying renewables.

Dynamic Fuels will produce the naval fuel at its Geismar, Louisiana plant using “U.S.-sourced yellow grease (used cooking oil) as well as Solazyme’s tailored algal oil as feedstocks.”  Several plusses ensue.  What would be disposable waste becomes a less-polluting energy source, frees the U. S. from part of its billion-dollar-a-day foreign oil obligation, and becomes part of Secretary of the Navy Ray Mabus’s commitment to run the Navy on at least 50-percent bio-fuel by 2020.

The video provides a look at how Dynamic Fuels refines tallow and other animal fats and wastes into a fuel good enough to run in your Rolls-Royce or GE turbofan engine.  As we develop more such alternatives, Secretary Mabus’ vision of freeing the United States from foreign wars in the service of protecting oil supplies may be closer to reality, and our energy independence may be more secure.

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Better Batteries: Nickel Cobalt Manganese from Ricardo and Axeon

by Dean Sigler on 01/09/2012

Ricardo and Allied Vehicles, a British engineering firm known for its work with racing vehicles and KERS technology, has announced an alliance with European battery manufacturer Axeon to produce a Nickel Cobalt Manganese (NCM) battery which would reputedly provide 35-percent greater range to electric vehicles than “existing technologies at the same weight.”

The new battery would require “50 percent less volume and 30 percent less mass when compared to Lithium Iron Phosphate chemistry at cell level,” according to the Richardo fourth quarter, 2011 newsletter.

Green Car Congress reports, “Electrochemically, the performance is superior to Lithium iron phosphate (LiFePO4) and Lithium cobalt oxide (LiCoO2) in terms of capacity and therefore energy density. In  terms of rate capability and therefore power density the electrochemical performance is better than LiCoO2 but not as high as LiFePO4, Axeon says.”  The chemistry compromise allows lower costs for these batteries.

With a Ricard-designed battery management system (BMS) the NCM pouch cells, new technology for EVs, can be blocked together into modular battery packs with the energy density of the new technology.

Axeon/Ricardo NCM battery module

Ricardo chief technology and innovation officer, Professor Neville Jackson, has greater goals for the new batteries.   “This project has allowed us to supply and develop our expertise in advanced battery management.   The new battery will improve the potential for more widespread vehicle electrification, a process that has the potential to significantly reduce global dependence on fossil fuels and minimize carbon dioxide emissions.”

Ricardo has used an “advanced demonstrator” vehicle to test the robustness and functionality of its BMS and “thermal management options” and overall vehicle range with the new battery modules.

In 2009, the Technology Strategy Board, the UK’s national innovation agency, awarded more than £680,000 (US$1 million) of funding to the consortium led by Axeon—bringing the total project funding to more than £1.3 million (US$2 million)—with the aim of developing an innovative high energy density battery system for an electric vehicle.  These tests will enable “Axeon to support rapid prototyping into a range of other vehicle types with significantly reduced development lead times.”

As an added benefit, Ricardo’s BMS can work with a wide variety of cell chemistries, actively balances cells, and “delivers diagnostic and prognostic information to the vehicle control system.”

The two companies are collaborating on commercializing their new technologies.

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Early Warning for Li-Pos

by Dean Sigler on 01/02/2012

Nobody wants an airplane fire.  You’re way up in the air, can’t pull over to the curb, and have limited means of quelling the flames.  The most energy-dense batteries, based on lithium chemistries, are subject to failure from physical and electrical abuse.  Most cells run through their promised cycle life without giving a hint of trouble, but sometimes fate or mischance leads to disaster.

Battery alternatives with lower risk usually possess lower energy and/or power density, crucial to use in aircraft, since weight is usually a primary consideration in vehicle design.

Lithium fires are quite often spectacular, probably a consideration that prompts Dale Kramer to recharge his 100 pounds of cells in his fireplace – with the flue wide open.  Even small cells found in laptop computers and cell phones have caused injury and death to their users.

For all lithium battery users, some reassurance may be found in news from the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Maryland.  Researchers there have developed a sensor that uses the “intrinsic relationship between the internal temperature of lithium-ion cells and an easily measured electrical parameter of the cell,” to warn of impending meltdowns.

“An abnormally high internal cell temperature is a nearly universal manifestation of something going awry with the cell,” says Rengaswamy Srinivasan, a chemist in APL’s Research and Exploratory Development Department and one of the inventors.  “These changes can occur within seconds, leading to a potentially catastrophic event if corrective measures are not taken immediately. When things start to go wrong inside the cell, time is not on your side.”

Most systems in aircraft have some form of a battery management system (BMS) which permits even charging and discharging of individual cells in a battery pack; and a protection circuit module (PCM) which protects the battery pack from overcharging, over-discharging, and excessive current either being applied to or drawn from the cells.

The APL researchers discovered a crucial element not found in existing battery management systems.  A small alternating current at specific frequencies is modified by a lithium cell “in such a way that is directly related to the temperature of the critical electrochemical interface between the electrodes and the electrolyte.”

“We discovered that we can measure the temperature of the protective layers between the electrodes and the electrolyte of the battery during normal operation,” Srinivasan says. “These layers are where the conditions that lead to thermal runaway and catastrophic cell failure begin.  This discovery enables us to detect potentially unsafe thermal conditions before surface-mounted temperature sensors, which are the current state of the art, are able to register that any change has taken place.”

A single sensor acting through an electrical connection at the positive and negative terminals of the cell can be powered by the battery it monitors and with multiplexing circuitry “can monitor multiple cells in a battery pack.”

Srinivasan hopes that battery makers will integrate APL’s new technology into their products, increasing safety and performance.  APL is in the process of applying for patents for the sensor and checking licensing agreements.

Ehow.com explains the mechanism of Lithium polymer fires.

LiPo batteries contain lithium. If lithium is exposed to air with even a slight amount of humidity, it can ignite, releasing hydrogen and other chemicals.
Hydrogen is extremely explosive, and is ignited by the burning lithium, resulting in a violent flare-up.

The usual cause of flare-ups is mishandling, which causes a buildup of gas in the battery, leading to a characteristic “LiPo puff” — the
swelling of the battery package. If the “puff” is large enough, the package may rupture, exposing the lithium to air.

LiPo batteries require chargers made specifically for them. Using the wrong type of charger is likely to cause a flare-up.

If too much current is drawn (“overloading”), the battery will become very hot and release gas internally.  The battery will rupture, exposing the lithium to air, resulting in a fire.

Anything that breaks open a LiPo battery pack, even a small puncture, will likely result in a fire.

And a good “as told to a friend” story helps illustrate the destructive potential of such conflagrations.

 

Hardly the way you want your 15 minutes of fame

A radio-control flyer left a 2,100 mAh pack in his minivan, plugged in to the charger/cell balancer.  He set the charger to “about 1,000 mAhs and left the van unattended for three or four minutes.  The three Lipo batteries in the front seat exploded, causing a fire that led to the subsequent explosions of the car battery, tires, and gas tank.  The flyer’s 15 minutes of fame came on the Channel 12 news that evening.

With news that electric and hybrid cars like Fiskers and Volts are being recalled for similar battery-related fires, early warnings of catastrophe are more than welcome.

 

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Going Over to the Dark Side

by Dean Sigler on 12/26/2011

The University of Texas at Austin’s press release spells out the quantum-like behavior of photons striking solar cells, and provides some insight into why obtaining higher efficiencies so far has perplexed researchers.

“AUSTIN, Texas — The efficiency of conventional solar cells could be significantly increased, according to new research on the mechanisms of solar energy conversion led by chemist Xiaoyang Zhu at The University of Texas at Austin.

“Zhu and his team have discovered that it’s possible to double the number of electrons harvested from one photon of sunlight using an organic plastic semiconductor material.

“’Plastic semiconductor solar cell production has great advantages, one of which is low cost,’ said Zhu, a professor of chemistry. ‘Combined with the vast capabilities for molecular design and synthesis, our discovery opens the door to an exciting new approach for solar energy conversion, leading to much higher efficiencies.’”

Pentacene stick and ball model

Zhu and his team published their discovery December 16 in the journal Science, under the title “Observing the Multiexciton State in Singlet Fission and Ensuing Ultrafast Multielectron Transfer,” although the abstract may bring more darkness than light to this modest attempt to enlighten.

“Multiple exciton generation (MEG) refers to the creation of two or more electron-hole pairs from the absorption of one photon. Although MEG holds great promise, it has proven challenging to implement, and questions remain about the underlying photo-physical dynamics in nanocrystalline as well as molecular media. Using the model system of pentacene/fullerene bilayers and femtosecond nonlinear spectroscopies, we directly observed the multiexciton (ME) state ensuing from singlet fission (a molecular manifestation of MEG) in pentacene. The data suggest that the state exists in coherent superposition with the singlet populated by optical excitation.  We also found that multiple electron transfer from the ME state to the fullerene occurs on a subpicosecond time scale, which is one order of magnitude faster than that from the triplet exciton state.”

The maximum theoretical efficiency of the silicon solar cell in use today is approximately 31 percent, because much of the sun’s energy hitting the cell is too high to be turned into usable electricity. That energy, in the form of “hot electrons,” is instead lost as heat. Capturing hot electrons “could potentially increase the efficiency of solar-to-electric power conversion to as high as 66 percent.”

The press release provides a four-point explanation of the quirky behavior that now limits solar cell efficiency, but also shows how the current causes of the waste heat could be exploited for greater gain.

  • Absorption of a photon in a pentacene semiconductor creates  an excited electron-hole pair called an exciton.
  • The exciton is coupled quantum mechanically to a dark  “shadow state” called a multiexciton.
  • This dark shadow state can be the most efficient source of  two electrons via transfer to an electron acceptor material, such as fullerene,  which was used in the study.
  • Exploiting the dark shadow state to produce double the electrons could increase solar cell efficiency to 44 percent.

Trying to capture that waste energy as reported in Science in 2010, Zhu and his team used semiconductor nanocrystals, but noted the challenges involved in that technology.

“For one thing,” said Zhu, ”that 66 percent efficiency can only be achieved when highly focused sunlight is used, not just the raw sunlight that typically hits a solar panel.  This creates problems when considering engineering a new material or device.”

As an alternative, the team discovered that a photon produces a dark quantum “shadow state” from which two electrons can then be efficiently captured to generate more energy in the semiconductor pentacene, an organic semiconductor consisting of five linearly-fused benzene rings.

This plastic semiconductor material can  apparently be easily and inexpensively manufactured, adding to its attractiveness for further research and development.

The UT press release continues, “Zhu said that exploiting that mechanism could increase solar cell efficiency to 44 percent without the need for focusing a solar beam, which would encourage more  widespread use of solar technology.

“The research team was spearheaded by Wai-lun Chan, a postdoctoral fellow in Zhu’s group, with the help of postdoctoral fellows Manuel Ligges, Askat Jailaubekov, Loren Kaake and Luis Miaja-Avila. The research was supported by the National Science Foundation and the Department of Energy.”

The Los Angeles Times, noting the new technology is “way  cheap,” reports, “All of this goes to reinforce a recent study by Joshua Pearce at Queen’s University in Kingston, Ontario, who found that cost estimates for solar technology used by energy analysts are greatly inflated. The technology is changing so fast that many studies don’t reflect the newest realities. For instance, the cost of solar panels has dropped 70% since 2009, and their productivity only declines 0.1% to 0.2% per year, rather than the 1% per year that was the norm.

“The bottom line? Commonly used studies have listed dollars-per-watt of electricity as high as $7.61. According to Dr. Pearce, the real cost in 2011 is under $1 per watt.”

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Going Vintage Electrically

by Dean Sigler on 12/24/2011

On December 21, 2011, Samy Dupland test flew Electravia’s latest adaptation of its electric power systems.  The Electrolight 2, a Fauconnet A60 on which Electravia head Anne Lavrand and Dupland mounted their 26 hp motor and power pack, is a French version of the Scheibe L-Spatz (Sparrow) standard class sailplane.

Fauconnet A60 with Electravia power package

With a 5.55 kilowatt hour lithium polymer battery pack, the electric microlight glider can stay up for one hour, 45 minutes or gain up to 3,000 meters (9,842 feet).  Its cruising speed is between 100 kilometers per hour (62 miles per hour) and 150 km/h (93 mph), with its range doubtless dropping at higher speeds.  Its maximum weight is 315 kilograms (693 pounds) with a recovery parachute, right at the limit for French ultralight rules.  Electravia sells the complete system of electric propulsion (motors, controller, batteries, instruments, propeller), and provides integration of the system into light sailplanes like the Fauconnet.

Several vintage sailplanes could be easily adapted to such a system.

Electravia’s blog reports a cost of half-a-Euro (65 cents) per charge, certainly a low fee for a sailplane launch, and certainly more independent in operation than waiting for the tow plane.  Charge times vary from 1 hour, 10 minutes for the smallest battery pack to 2 hours, 40 minutes for the largest on a single-phase power line and from 40 minutes to 1 hour, 20 minutes on a three-phase line.

Electrolight 2 in flight

A traditional 1960’s soaring vehicle, the Fauconnet has a steel-tube fuselage, wood wings, and a translucent fabric covering.  The 34 kilogram (74.8 pound) battery pack is the largest of three available and limits pilot weight to 86 kilograms (190 pounds).  Smaller packs allow shorter climbs and limited duration, but allow for pilots up to 106 kg (233 pounds) while supporting limit loads of +4 g and –2 g and maximum loads of +6 and -3 g.

The instrument panel, despite its steam gauges, sports an OLED E-Screen that shows battery discharge, motor temperature, motor current, battery current and voltage, and that records all data on an SD card.

Electravia’s package enables a soaring pilot to convert a relatively inexpensive sailplane to self-launching status and fly independently at very little cost.  This makes the idea highly attractive and should help spread the idea of electric flight to a new audience.

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Concentrating Sunlight

by Dean Sigler on 12/18/2011

The promise of solar energy is that, for all practical purposes, solar energy is unlimited and eternal (if the sun goes away, we go away).  Despite this, only four percent of the world’s energy needs are supplied by solar resources today.  Part of this is the relatively high cost of solar cells, their limited efficiency, and sometimes limited lifespans, which makes expensive replacements a regular necessity.

The total amount of solar energy striking the earth is a strikingly high figure, something in the way of terajoules, according to one site.  About 1,000 Watts of energy hit every square meter of the earth’s surface, varying by the angle at which the surface is tilted relative to the parallel rays from the sun.  Most solar cells fall into a 12-to-40-percent efficiency range, though, limiting a photovoltaic array’s output to about 120 to 400 watts per square meter (10.76 square feet) at the best angle.

That’s part of what makes solar aircraft problematical.  Solar Impulse makes up for this lower overall energy capture by presenting huge surface areas to the sun.  Almost all solar aircraft have a battery backup in their wings.  Recharging in non-flying times or during slow cruise enables these craft to extract the extra power necessary for takeoff and climb.  Large wings and tail surfaces provide the area to collect the energy, but the large wing area necessary to allow flight on limited power also limits the speed at which these craft can travel.  But even 100-percent efficient cells would limit total energy available to about 10 kilowatts on a 100-square-foot wing, and that only if the sun were directly overhead.

A possible way to reduce the square footage required to generate sufficient energy may be found in a Small Business Innovation Research (SBIR) contract between Entech Solar, Inc., a Fort Worth, Texas based company and NASA’s Glenn Research Center.  With similar designs using different materials, Entech is able to provide solar power to space ships or to utility-sized arrays for more terrestrial applications.  The approach is in the process of being commercialized.

Entech concentrated solar panel

Using a concentrating photovoltaic (CPV) technology, sunlight can be focused to 20 times its normal intensity, reducing the silicon requirement for an energy output equivalent to non-concentrated flat-plate cells by 93 percent, according to the manufacturer.  This smaller use of expensive materials allows low cost for large installations, an important factor for utilities.

The same linear lens forms are used in space applications, but cell and other materials are of a higher quality and therefore of a greater cost than their earth-bound counterparts.  In many concentrating PV panels, heat buildup requires liquid cooling or a significant heat sink to keep things at a tolerable temperature.  Entech claims that, “By using smaller lenses, the aluminum housing provides all waste heat rejection, eliminating the need for a heavy and expensive heat sink.”

Even with the small amount of silicon used, the panels produce electricity with 30-percent efficiency, according to Entech.  This would certainly allow more power to electric aircraft if this technology can be adapted at a cost somewhere between utility-grade and space-grade panels.

You can review Entech’s specification sheet for their SolarVolt™ panels here.

 

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Horizontal or Vertical, in the Air or on the Water

by Dean Sigler on 12/15/2011

A 2008 ScienceDaily story was brought to light recently in the Minimalist Airplane Study Group, a Yahoo group dedicated to academic research on small aircraft.

“In an advance toward introduction of an amazing new kind of internal combustion engine, researchers in China are reporting development and use of a new and more accurate computer model to assess performance of the so-called free-piston linear alternator (FPLA).”

Their study of the FPLA, which could provide a low-emission, fuel efficient engine for future hybrid electric vehicles, was published in the August 27, 2008 issue of The American Chemical Society’s Energy & Fuels, a bi-monthly, peer-reviewed journal.

Qingfeng Li, Jin Xiao and Zhen Huang explain in their paper that the FPLA has only one moving part and is an engine designed to generate electricity. “In the device, a piston in a cylinder shuttles between two combustion chambers. Permanent magnets on the piston generate electricity by passing through the coils of an alternator centered on the cylinder. The engine can burn a variety of fuels, including natural gas and hydrogen, and seems ideal use in a future world of climate change and possible fossil fuel shortages, they suggest.”  This would seem suited to internal and external combustion approaches.

The team was working on an improved computer model to evaluate the performance of their device and to “guide engineers in the construction of the engine.”

Free-piston linear accelerator. Think about this with a Halbach array.

Despite a “look” that would suggest (at least to this uninitiated observer) a rough plunging back and forth beween the two ends of the assembly, computer simulations “showed that the FPLA could
accelerate three times faster than other internal combustion engines and burn fuel in ways that minimize air pollution.”

Electricity generated by the alternator could be shared by distributed motors in electric vehicles, including aircraft.

This is of interest because several other developers are coming forward with fuel-driven range extenders for automobiles, and because, serendipitously, Oregon State University researchers are building a series of wave generators to be installed off the Oregon coast, which use a linear system very much like that of the Chinese researcher’s hybrid motor.  Imagine the possibilities with a Halbach array as the linear generating source.

An area off the coast of Reedsport, Oregon was found in various studies to have the best combination of waves to generate mass quantities of power for the region.  Oregon Iron Works has crafted the first large generators and researchers are in the process of creating the first array of generators.  Other similar systems have been or are being installed off the coasts of New Jersey, Hawaii, and Spain.

The self-contained hybrid technology inherent in the engine form is one of many such devices being introduced, and we will look at some of these in upcoming blog entries.

 

 

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