Yes there are criticisms of electric vehicles, probably the most commonly-heard is that their batteries take far too long to recharge – after all, limited range wouldn’t be such a big deal if the cars could be juiced up while out and about, in just a few minutes. Well, while no one is promising anything, new batteries developed at the University of Illinois, Urbana-Champaign do indeed look like they might be a step very much in the right direction. They are said to offer all the advantages of capacitors and batteries, in one unit.

“This system that we have gives you capacitor-like power with battery-like energy,” said U Illinois‘ Paul Braun, a professor of materials science and engineering. “Most capacitors store very little energy. They can release it very fast, but they can’t hold much. Most batteries store a reasonably large amount of energy, but they can’t provide or receive energy rapidly. This does both.”

The speed at which conventional batteries are able to charge or discharge can be dramatically increased by changing the form of their active material into a thin film, but such films have typically lacked the volume to be able to store a significant amount of energy. In the case of Braun’s batteries, however, that thin film has been formed into a three-dimensional structure, thus increasing its storage capacity.

Batteries equipped with the 3D film have been demonstrated to work normally in electrical devices, while being able to charge and discharge 10 to 100 times faster than their conventional counterparts.

To make the three-dimensional thin film, the researchers coated a surface with nanoscale spheres, which self-assembled into a lattice-like arrangement. The spaces between and around the spheres were then coated with metal, after which the spheres were melted or dissolved away, leaving the metal as a framework of empty pores. Electropolishing was then used to enlarge the pores and open up the framework, after which it was coated with a layer of the active material – both lithium-ion and nickel metal hydride batteries were created.

The system utilizes processes already used on a large scale, so it would reportedly be easy to scale up. It could also be used with any type of battery, not just Li-ion and NiMH.

The implications for electric vehicles are particularly exciting. “If you had the ability to charge rapidly, instead of taking hours to charge the vehicle you could potentially have vehicles that would charge in similar times as needed to refuel a car with gasoline,” Braun said. “If you had five-minute charge capability, you would think of this the same way you do an internal combustion engine. You would just pull up to a charging station and fill up.”

Braun and his team believe that the technology could be used not only for making electric cars more viable, but also for allowing phones or laptops to be able to recharge in seconds or minutes. It could also result in high-power lasers or defibrillators that don’t need to warm up before or between pulses.

Sourced & published by Henry Sapiecha

High school teacher

creates microfluidic devices

using a photocopier

A high school physics teacher has invented a method of producing microfluidic devices, using little else than a photocopier and transparency film

Microfluidic technology, in which liquid is made to pass through “microchannels” that are often less than a millimeter in width, has had a profound effect on fields such as physics, chemistry, engineering and biotechnology. In particular, it has made “lab-on-a-chip” systems possible, in which the chemical contents of tiny amounts of fluid can be analyzed on a small platform. Such devices are typically made in clean rooms, through a process of photolithography and etching. This rather involved production method is reflected in their retail price, which sits around US$500 per device. Now, however, a high school teacher has come up with a way of making microfluidics that involves little else than a photocopier and transparency film.

Joe Childs, who teaches physics at Massachusetts’ Cambridge Rindge and Latin School, collaborates with Harvard University’s School of Engineering and Applied Sciences (SEAS), via the National Science Foundation’s Research Experience for Teachers program. As part of that program, he devised a quick, simple and inexpensive method of creating reusable labs-on-a-chip.

He starts by designing the layout of the microchannels in PowerPoint, printing that image, then photocopying it onto a sheet of classroom-style transparency film. The same sheet is ran through the photocopier repeatedly, until the ink builds up sufficiently to create a raised relief model of the channels. That model serves as a negative mold, which is used to create the final working channels in a polymer chip.

Childs is now working with SEAS Director of Instructional Technology Dr. Anas Chalah, to perfect the system. Already, he says, they can design and build a chip in a single afternoon. Although the photocopier microfluidics are not as precise as their commercially-produced counterparts, they could prove to be an invaluable educational aid for physics students, who will be able to design and build their own microfluidic devices.

All photos courtesy Harvard University.

Sourced & published by Henry Sapiecha

boosts efficiency of solar cells

In order for a solar cell to be as efficient as possible, the last thing it should be is reflective – after all, light should be getting absorbed by it, not being bounced off. With that in mind, a few years ago a group of Japanese scientists set out to create an antireflective film coating for use on solar cells. What they ended up creating utilizes the same principles that are at work in one of nature’s least reflective surfaces: moth’s eyes.

The moth-eye film was developed by Noboru Yamada, a scientist at Nagaoka University of Technology Japan, who collaborated with researchers at Mitsubishi Rayon Co. Ltd. and Tokyo Metropolitan University. Using anodic porous alumina molds, they were able to nanoimprint the microstructure of moth’s eyes into acrylic resin – this provided a high throughput, large-area/low-cost method of producing the film.

Based on the results of indoor and outdoor tests of crystalline silicon solar panels coated with the film, the team’s computer models indicated that use of the film could boost the annual efficiency of solar cells by five percent in Tokyo, and six percent in the “sun belt” city of Phoenix. “People may think this improvement is very small, but the efficiency of photovoltaics is just like fuel consumption rates of road vehicles,” said Yamada. “Every little bit helps.”

They are now working on improving the durability of the film, and optimizing it for use on different types of solar cells. They are also looking into using it to reduce glare on surfaces such as windows and computer screens, although in that area they may be facing some competition – Germany’s Fraunhofer Institute for Mechanics of Materials has already developed an anti-reflective coating for use on displays and eyeglasses, which was also inspired by moth’s eyes. In Franuhofer’s case, the coating is incorporated into the viewing surface during the molding process, instead of being added afterward in the form of a film.

The reasons that moths have anti-reflective eyes, incidentally, is to allow them to gather as much light as possible in the dark, and to avoid being seen by predators.

The moth-eye film research was recently published in the journal Energy Express.

Sourced & published by Henry Sapiecha

Powering Up

The Battery-Free World

Sensors and Microcontrollers, Too!

Sensors are another type of peripheral components evolving rapidly. Sensors designed to acquire information such as temperature and humidity are shrinking and consuming less power. The brightness sensors used to control lighting, for example, are being mounted on mobile phones now, and over the past few years current consumption has droppedto one-fifth. A source at Avago Technologies, Inc. of Japan says “We’ve confirmed that we can maintain sensitivity while suppressing noise, even running on low voltage.”

The microcontrollers used to control energy harvesting circuits and sensor drive are also showing up in lower-power versions. One widely used design is the MSP430, from Texas Instruments Inc. (TI) of the US, which sells for as little as US$0.25 apiece.

Fig. 5 Standby Current a Key Point

In applications such as wireless sensor networks, standby time is significantly longer than actual operation time. (Diagram by Nikkei Electronics based on material courtesy Renesas Electronics)

The key points in microcontrollers are a low standby current consumption, and a very short wake-up time. Operation is intermittent in almost all wireless sensor networks, so standby current consumption is crucial. A comparison of this characteristic alone shows that 16-bit microcontrollers from Renesas Electronics Corp. of Japan have current consumption low enough to put them at the very top of the list for candidates (Fig. 5).

Thermoelectric Conversion Devices through Thinfilm Technology

In addition to merely improving the characteristics of peripheral components, however, other firms are working on the generating devices that are the heart of energy harvesting. For example, a thermoelectric conversion device with high electromotive force has appeared. Slated for volume production start in 2011, the device comes in a small, thin package, and can get 140mV from a temperature difference of about 1°C. Conventional devices measuring several cm on a wide can usually generate only about 50mV.

Fig. 6 Miniature High-Performance Thermoelectric Converters

Micropelt has begun supplying thermoelectric conversion devices, and modules using them (a). Made with thinfilm technology, they can provide satisfactory generating capacity even in small sizes (b). (Diagram by Nikkei Electronics based on material courtesy Micropelt)

The device was developed by Micropelt GbmH of Germany. Wladimir Punt, Vice President, Sales & Marketing at the firm, is confident in the technology: “We are constructing a plant now that will be able to manufacture 10 million modules annually.” Engineers applied thinfilm technology to create a device combining small size with high efficiency (Fig. 6) ^{Note 5)}.

Note 5) In manufacturing, n-type and p-type devices are sputtered individually on separate wafers, which are then sandwiched together in alternation.

Sourced & published by Henry Sapiecha

No Power through

Energy Harvesting:

Powering Up

the Battery-Free World

Stepping Up from only 20mV

Co2 to energy

The impact of higher power supply circuit performance is dramatic, because just how efficiently the power supply can handle the minute trickles of power gained through energy harvesting-how little loss there is-is key. Recently, even ultra-low voltages can be harvested efficiently.

Linear Technology Corp. of the US began volume production of the LTC3108 DC-DC converter, offering relatively high step-up efficiency from even an extremely low 20mV, in December 2009. With a thermocouple, the firm says, it can produce electricity from a temperature difference of only 1°C. An engineer involved in power supply circuit development for years is amazed: “They can use voltages a whole order lower than we can as energy sources!” ^{Note 2)}.

Note 2) The LTC3108 uses an internal n-channel metal oxide semiconductor field effect transistor (MOSFET) with external step-up transformer and capacitor, forming a resonant step-up oscillator. A transformer with a 100:1 ratio would boost 20mV to 2.0V.

According to Tony Armstrong, Director of Product Marketing, Power Products at Linear, the firm began development of the LTC3108 in about the summer of 2007, predicting growth in the energy harvesting field.

Ultra-Low Dissipation Wireless ICs

Lower dissipation by wireless transceiver ICs has also had an enormous effect, along with power supply circuits. Standby dissipation, previously about 1?A, has now been slashed to about 0.2?A thanks to smaller geometry and innovations in communications control.

One company that stands out in the energy harvesting field when it comes to wireless transceiver ICs is venture firm EnOcean GmbH of Germany. The amount of power consumed by the firm’s “EnOcean” standard for wireless communication between equipment is one digit smaller thanother methods.

Fig. 4 EnOcean Emphasizes Low Power Consumption and Ease of Use

The single design means a signal is sent only three times in 30ms (a), helping reduce standby current to only 0.2?A (b). The wavebands used vary by nation and region. Ease of use has been enhanced by modularization (c).

Power consumption was slashed by eliminating unnecessary functionality. Frank Schmidt, Chief Technical Officer (CTO) of the firm, stresses the key is simple control. Wireless ICs used in switch applications, for example, send only three 1ms signals every 30ms for on/off control (Fig. 4) ^{Note 3)}.

Note 3) The latest specification further improved convenience by supporting feedback from the receiver to the transmitter.

There are also efforts under way to apply low-power wireless LAN to energy harvesting wireless communication. GainSpan Corp. of the US, with founders including engineers from Intel Corp. of the US, has developed a wireless LAN IC with a standby current consumption of no more than 1?A: between 10% and 1% of standard designs ^{Note 4)}. This is about the same level as ZigBee. It offers an advantage in that existing wireless LAN access points can be utilized. Standardization has also started on ZigBee Green Power, however, a version of ZigBee tweaked for energy harvesting applications. The standard is expected to be finished by the end of 2010.

Note 4) Lower dissipation was achieved in part by frequent clock gating and use of sleep mode.

Sourced & published by Henry Sapiecha

Powering Up

the Battery-Free World

The enormous attention garnered by the growing market, in spite of the tiny amounts of power available, is due to the high convenience it promises. The major selling point for energy harvesting is that equipment can use it to eliminate primary battery replacement, wiring and maintenance (Fig. 2). It will mean a switch from low power to no power.

Fig. 2 Battery-Free Design for Enhanced Convenience

The key point is that primary batteries and wiring are no longer needed (a). Vibrator “battery” combines a capacitor and generator (b). The same size as a battery, it can be swapped into a remote control. A remote control for relay truck jacks was jointly developed by NHK Toyama Broadcasting Station and Yuasa (c), driven by the force of the finger pressing the buttons.

The range of applications is gradually expanding as industry makes an effort to realize this convenience. The Hoki Museum in Chiba City, Chiba prefecture, which opened on Nov. 13, 2010, for example, adopted energy harvesting technology for voice guidance switches. The system is already in operation.

Control signals are handled via wireless, eliminating the need for new wiring for the switches. Setting up the power cables and other wiring for frequently changing exhibits has always been a major load for art museums, and energy harvesting’s wire-free strengths are invaluable here.

Changing Peripheral Components

A representative energy harvesting system consists of four major steps, namely (1) detecting the energy source and generating electricity, (2) converting the acquired electricity as needed in a power supply circuit for storage in capacitors or rechargeable batteries, (3) using the stored power to drive microcontrollers and sensors, and (4) using a wireless transceiver to pass information acquired from sensors to the outside world ^{Note 1)}.

Note 1) The price of a unit implementing these four functions, according to Linear Technology’s Armstrong, is “about US$12 in lots of 50,000.”

The concept of energy harvesting is quite old, and research in the field also has a long history. The rapid expansion in application fields of late is due to evolution in the peripheral components to make best use of the generating devices, corresponding to steps (2) through (4) above. This evolution has made it possible to utilize the technology in an increasing range of applications.

Fig. 3 Generated power Exceeds Self-Consumption

The performance of generating devices is rising, while the power needs of peripheral components drops. The appearance of high-tech startups with superior technical expertise is especially significant in radio transceiver ICs, which dissipated the most power.

Peripheral component evolution here refers to significant reductions in power consumption by the power supply circuits needed to efficiently utilize generated power, the wireless ICs that send and receive signals, microcontrollers and sensors (Fig. 3). Until recently, the electricity collected by the generating devices was expended by the peripheral components themselves, making the target function impossible to achieve. Now that there are a number of ICs available with high-efficiency, low-dissipation circuits, energy harvesting has finally entered the realm of the practical.

Received & published by Henry Sapiecha

through Energy Harvesting:

Powering Up

the Battery-Free World

Vibration from people walking or cars crossing bridges, automobile heat, broadcasting waves and more: Energy harvesting makes it possible to utilize the uptapped energy all around us. While the available electric power is small, the world is fascinated by the concept of eliminating the need for primary batteries… More and more applications are becoming possible as the characteristics of peripheral components are improved, and high-efficiency wireless ICs running on minimal power are driving expanded introduction.

Energy harvesting refers to collecting the minute amounts of energy in our immediate surroundings, such as vibration, light, heat and electromagnetic radiation. This concept of efficiently tapping the minute amount of energy that we casually discard today is attracting enormous interest.

“The energy harvesting equipment market will grow from US$650 million in 2010 to US$4.4 billion in 2020,” predicts IDTechEx Ltd. of the UK. ¹⁾ Innovative Research and Products, Inc. of the US adds “The 2009 market is US$79.5 million, but that will grow at an annual rate of 73.6% to reach US$1.254 billion in 2014.” ²⁾

“Battery-Free” the Major Selling Point

Also known as environmental energy harvesting and energy scavenging, energy harvesting offers the advantage of being able to generate power in diverse locations (Fig. 1). The energy gained, however, is extremely small (Table 1), ³⁾ with output power on the ?W order for the majority of generating devices. It is unlikely to be able to provide enough energy to make it unnecessary to charge smartphones, for example.

Fig. 1 Diverse Energy Sources All Around Us

Energy harvesting is a technology to efficiently “harvest” and utilize minute amounts of energy currently being discarded. Energy sources include vibration, light, heat and electromagnetic radiation. (Illustration: Reiko Kusumoto)

Table 1 Common Minute Energy Sources

Received & published by Henry Sapiecha

G-Power claims world’s fastest sedan title with 372 km/h modified BMW M5

German tuning company G-Power is claiming to have set the record for the world’s fastest sedan with a BMW M5. G-Power’s M5 Hurricane RR achieved a top speed of 372 km/h (231 mph) beating its own record of 367.4 km/h (228 mph) set earlier this year. But it’s not just the two-ton vehicle’s top speed that’s impressive – it can accelerate from 0 to 100 km/h in 4.35 seconds, up to 200 km/h in 9.5 seconds and up to 300 km/h in 25.8 seconds. Read More

Sourced & published by Henry Sapiecha

Energy efficient lighting e-Bulletin

On 21 July 2010 QWESTNet held its second lighting forum in Brisbane. Held in association with

the Illuminating Engineering Society (ies), the forum focused on energy efficient lighting

technologies including LEDs, lighting controls and the use of daylight.

Click on ‘listen to presentation’ or the presenter’s photograph to hear the presentation

ies Partner Presentation
Presenter:Gillian Isoardi
ies/University of Queensland
Listen to Presentation

Gillian’s presentation gives an overview of the role of IES and outlines the positive reasons

for businesses to pursue energy efficient lighting.  Adhering to best practices in lighting will

ensure an installation that meets the needs of all users. Further benefits can, of course,

be realised by lowering operating costs of buildings but also by improving the quality of

workspaces and the appearance of products.

LED: good, bad and best practice
Presenter: Gorana Jusufovich
Lumascape
Listen to Presentation

A brief discussion of some of the benefits and pitfalls of using LED

based lighting systems. How do LEDs compare to conventional light

sources; what to be aware of when selecting an LED based lighting product; and busting

some of the myths surrounding LEDs.

Facility management and lighting controls
Presenter:Lance Stewart
Creative Lighting
Listen to Presentation

Why do we need lighting control systems and what do we need from them?

Can best lighting practice be achieved under the Building Code of Australia

and what is good lighting practice any way? Lance discusses recent trends in efficient lighting

and control.

Daylighting and Greenstar
Presenter: Carl N Gray
MGF Consulting NQ
Listen to Presentation

A brief primer on daylighting as applicable in Queensland workplaces,

specifically what can and cannot be done with daylight? Why we should

do more; why we should be very careful about it; how it can be done; and who to ask.

Top

Case Studies

Queensland Police Service fit-out Presenter: Caitlyn Young Norman Disney & Young Listen to Presentation The Queensland Police Service CBD facility fitout was completed in 2004/2005. Utilising an Energy Conservation Systems (ECS) lighting control system, occupancy based switching and daylight harvesting have delivered an efficient lighting design and flexibility for future changes. The integration of this system has led to a significant saving in energy and CO2 emissions. William McCormack Place Presenter: Carl N Gray MGF Consulting NQ Listen to Presentation The Queensland Government’s newest office building located in Cairns has attained ‘World Leader’ green status – the first outside of a capital city. In line with the lighting engineer’s vision, an emphasis on real world performance was placed before Greenstar ‘point scoring’ to achieve a highly energy efficient yet highly comfortable building. Highlights include effective daylighting and shading, a novel approach to daylight harvesting, direct/indirect lighting and the integration of ceiling fans. Queesland Performing Arts Centre (QPAC) Presenter: Doug Brimblecombe QPAC Listen to Presentation Between November 2008 and March 2009, QPAC refurbished its major theatres and public spaces for the first time since the centre was constructed 25 years ago. This was an opportunity for QPAC to introduce more efficient lighting practices without compromising the nature of the building and its use. As part of the refurbishment, aged incandescent and large wattage fixtures were replaced with LED and halogen lights. In the Concert Hall auditorium, the original 2500 watt profiles were replaced with three-colour LED lighting and theatrical fixtures, each of 1200 watts. These changes have minimised the amount of lights required to produce colour on stage, while backstage, single watt LED bulbs have replaced 60+ watt ‘blue’ light circuits. One year and three months after the refurbishment, QPAC is seeing energy savings which are expected to improve with further work due to be completed by the end of 2010. CitySwitch Program Presenter: Mark Taylor Brisbane City Council Listen to Presentation Brisbane City Council is partnering in a national office tenant energy management program called CitySwitch Green Office. This program gives your business: a structured process to improve energy efficiency and operating costs; positioning and promotion as an environmental leader; networking opportunities with like-minded companies; regular updates and resources. Key elements to effective lighting Presenter: Darrin Schreier Aurecon Listen to Presentation Efficient lighting is something everybody appears to be looking for, whether it be to meet legislated government criteria, to achieve a Greenstar or NABERS rating, or to save money in the face of rising energy costs. To achieve efficient lighting 4 key elements need to be addressed. Energy efficiency regulation and quality lighting Presenter: Steve Coyne Light Naturally Listen to Presentation There are two levels of energy efficiency which have the potential to affect quality lighting outcomes: energy efficiency of lighting product and energy efficiency of lighting design. The type of regulatory tool implemented for each can have a significant impact on quality lighting outcomes and compliance levels. Whatever form the regulation takes, it is apparent that in the future, quality lighting outcomes will require knowledge, expertise and training in lighting design Received & published by Henry Sapiecha

With a 65-Percent Efficiency

Science (June 17, 2010) — Eindhoven University of Technology (TU/) researchers want to develop solar cells with an efficiency of over 65 percent by means of nanotechnology. In Southern Europe and North Africa these new solar cells can generate a substantial portion of the European demand for electricity. The Dutch government reserves EUR 1.2 million for the research.

The current thin-film solar cells (type III/V) have an efficiency that lies around 40 percent, but they are very expensive and can only be applied as solar panels on satellites. By using mirror systems that focus one thousand times they can now also be deployed on earth in a cost-effective manner. The TU/ researchers expect that in ten years their nano-structured solar cells can attain an efficiency of more than 65 percent. Jos Haverkort: “If the Netherlands wants to timely participate in a commercial exploitation of nanowire solar cells, there is a great urgency to get on board now.” The research is conducted together with Philips MiPlaza.

They think that nanotechnology, in combination with the use of concentrated sunlight through mirror systems, has the potential to lead to the world’s most efficient solar cell system with a cost price lower than 50 cent per Watt peak. In comparison: for the present generation of solar cells that cost price is 1.50 euro per Watt peak.

Stacking Nanowires make it possible to stack a number of subcells (junctions). In this process each subcell converts one color of sunlight optimally to electricity. The highest yield reported until now in a nanowire solar cell is 8.4 percent. Haverkort: “We expect that a protective shell around the nanowires is the critical step towards attaining the same efficiency with nanowire solar cells as with thin-film cells.” Haverkort thinks that at 5 to 10 junctions he will arrive at an efficiency of 65 percent.

Scarcity of raw materials In addition, the researchers expect considerable savings can be made on production costs, because nanowires grow on a cheap silicon substrate and also grow faster, which results in a lower cost of ownership of the growth equipment. What is more, the combination of the mirror systems with nanotechnology will imply an acceptable use of the scarce and hence expensive metals gallium and indium.

An agency of the Ministry of Economic Affairs, will grant the EUR 1.2 million to researchers dr. Jos Haverkort, dr. Erik Bakkers en dr. ir. Geert Verbong for their research into nanowire solar cells. It is their expectation that, when combined with mirror systems, these solar cells can generate a sizeable portion of the European electricity demand in Southern Europe and North Africa.

Sourced & published by Henry Sapiecha