November 23, 2011 — The co-located Energy Harvesting & Storage and Wireless Sensor Networks & RTLS USA 2011 conference were held in Boston, MA recently. Following are highlights from the keynoters.
Clay Maranville from the FORD Motor Company discussed how FORD developed thermoelectric generators for their vehicles. Waste-heat recovery is part of the company’s strategy on sustainable transportation. Energy efficiency in transportation will be increasingly important, with China’s car ownership soaring to 230M by 2030 and rising fuel costs. Decreasing energy consumption is an "economic as well as an environmental" neccessity.
Reducing total fuel consumption, weight and cost compared to an alternator/battery system would be the ideal way to implement thermoelectric energy generation. Replacing the alternator completely is a very challenging approach though so, at this point, supplementing it is a much more viable option. Recovering waste heat without interfering with the rest of the systems on the vehicle was a central development consideration and results on a vehicle demonstrated the recovery of around 275W at cruising speed.
Clay also briefly touched on wireless vehicle sensors, with considerations including the potential elimination of 1500 different types of wires, (over 4km in length, 40kg in weight) with reduced cost, weight and improved long term durability wireless solutions.
Michael Balthasar, the Volvo Group, picked up the vehicle conversation from a commercial-use standpoint. The thermodynamic Rankine cycle approach is currently preferred due to higher efficiencies but thermoelectric generation is also important, where considerations at Volvo include lower cost, higher efficiency, and use of non-toxic materials. Such developments would make thermoelectric generation a preferred option.
Cost considerations are also important in the wireless sensors space: including product, manufacturing, development, and maintenance costs. Signal interference and cross communication have to be avoided and security of wireless communications is a high priority, making sure it is implemented with minimal energy consumption.
Warren Kronberger from The Marketing Store shared the perspective of a marketing company. Energy harvesting technologies could improve everything from promotional toys to furniture, replacing toys’ batteries for proximity and sound sensors, for example. Some interactive electronic toys (first introduced in 2003) are at times deployed in very large volumes of over 30,000,000 units in the space of a month and so, the overall opportunity in terms of harvesters necessary could be significant. Harvesting ambient energy would enable more interactive retail applications as well, with window signage and packaging, among other applications. In any implementation, safety is extremely relevant. Kronberger noted that the close proximity and increased interaction of the consumer with these types of products makes avoiding lead and other toxic materials, and other issues, crucial.
Dr Kars Michiel Lenssen from Philips Research Laboratories discussed electronic skin development, in collaboration with HP, and its power requirements in autonomous devices. Electronic skin describes the change of the appearance of surfaces electronically and remotely, with large size examples including smart windows and electronic wallpaper (managing lighting, privacy, temperature, etc). Consumers have shown that the application is interesting in theory, but excessive cabling and higher electricity bills are strong deterents. Energy harvesting and wireless solutions are a perfect solution. Electrophoretic displays are one approach, being able to easily control transmission rates from 0 to 70% with 5 levels of grayscale in between with low power consumption (zero power consumed to maintain dark state, nanoWatts to maintain transparent state, milliWatts during changing states). The size of implementation ranges from portable electronics personalization all the way to potentially changing the colour of one’s entire home depending on weather conditions and whether one would desire to keep a building warmer or cooler.
Dr Lenssen also announced for the first time HP’s development of a technology based on electrokinetics. The electrokinetic panels are manufactured on a roll to roll process and can also operate with very little power provided, whether by indoor PV or RF power.
Professor Manos Tentzeris, Georgia Institute of Technology, discussed Georgia Tech’s research, including long range wireless power transfer (5-6 miles) as well as multiple mode energy harvesting and electronic skin applications. The research group’s work on wireless sensor nodes follows a "three in one" approach, developing sensors, communication as well as power, integrating high efficiency nanotechnologies as well as low cost substrates. Paper electronics is one of the low cost substrate approaches, with examples such as RFID inkjet printed on paper. The substrate can be made hydrophobic (can be washed, rained upon) with 20 micron inkjet accuracy.
Inkjet-printed carbon nanotubes can be used as gas sensors due to their high sensitivity to nitrogen, detecting ammonia, nitrogen compounds etc, with applications including efforts to develop ways to stopping leakages before they become catastrophic.
The prolific group has also demonstrated solar smart skin for structural health monitoring, powering strai gauges and has shown how broadband RF harvesting can produce useful amounts of power, whereas narrowband gives very little power.
Richard Smith of One Laptop Per Child (OLPC) discussed the main needs of the highly ambitious project, and its charitable efforts to provide children all over the world with the necessary tools to promote education and opportunities even where availability of resources is scarce. Low power requirements, fault tolerance and robustness as well as mostly inexpensive devices (although current devices need to get to lower price point), with sunlight readable display are some of the main points Richard made during his presentation. OLPC has produced 2.2 million laptops since 2006, mostly deployed in Latin America. The 3rd generation of laptops goes into production in 2012 and there’s a tablet device under design as well.
Off grid power remains a challenge as there is no "one size fits all" solution at different sites, different environments, cultures, social requirements (e.g. Mongolia vs Kenya). Options discussed included hand cranks, waterwheels, and even "cow power."
Since for the developing world, the size of a laptop battery is meaningless – as Richard said during his presentation "How big does your battery have to be if there is no place to plug it in?"- opportunistic charging is the way forward: high charge rate, low power draw and being humanly feasible (relying on power you generate yourself) are the three main requirements for it. According to OLPC the ideal ration of charging time over runtime achieved is 1 to 10: 10 minutes charging for 100 minutes of runtime. That’s the kind of device the charity is working towards.
Infinite Power Solutions’ Joe Keating closed the keynote sessions with an overview of the ways the company is implementing complete solutions to energy harvesting requirements for further deployment of wireless sensor networks. The company’s proprietary solid state battery technology, the Thinergy Micro-energy Cells, along with collaborative work with leading low power electronics companies and energy harvester developers has led to a multitude of demonstrators that were showcased at the conference and tradeshow. During the IPS presentation, Keating discussed the topic of optimization of DC to DC buck conversion, in order to get the maximum possible energy out of storage cells.
The Energy Harvesting & Storage and Wireless Sensor Networks & RTLS series of events next heads to Berlin, Germany for May 15-16, 2012. For full information, visit www.IDTechEx.com/eh.
More on energy harvesting.
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What I love about this blog from Analog Devices’ Marketing Program Manager, Howard Wisniowski, is that it starts with the simple idea of making human motion smarter through technology. Last year I broke my ankle while running (avoiding a truck and I fell in a ditch…but I digress). If I had the inertial motion technology described below, perhaps I could have avoided injury and be a smarter, more efficient runner. Think it’s science fiction, a la Bionic Woman? Nope. As this blog will tell you, the technology is here and is being applied in very real-world examples that will revolutionize the way we interact with our environment, thanks to the MEMS inside. Enjoy — Karen Lightman, Managing Director, MEMS Industry Group.