By Florian Schumacher, Wearable Technologies.com

http://www.wearable-technologies.com/2014/07/energy-harvesting-for-wearables/ 

 

 

ED NOTE: The wearable tech industry is poised for massive growth. Forecasts predict worldwide spending on wearable technology will reach $19 billion by 2018. Several factors are converging to facilitate wearable technology integration including: Expanded wireless capacity due to pervasive wireless (WiFi, WiMAX, and LTE); and the significant backing from huge companies including Google, Apple, and others.

 

 

One of the main difficulties with wearables is how to provide enough energy for the electronics to run over a reasonable amount of time without making the battery too large or the device bulky. In an ideal world, users would not have to charge their wearables at all. But considering the wearables of today even increasing the battery life by a few days would be a huge improvement.

 

The term energy harvesting summarizes several different approaches which might lead us a step closer to such an ideal world. Instead of charging wearables with some sort of cable, new wearables could produce the energy they need from the light, heat or vibration in their surroundings. That might sound like science fiction, but energy-harvesting wearables have been around for many years. Automatic watches have been converting the energy from arm movements for a while now and Seiko has even invented an electromagnetic generator that powers its quartz watches by its wearers' physical movements.

 

For today's era of wearables that rely heavily on sensors, computing power and communication technology a simple approach to energy no longer is sufficient. However, there is a whole range of new technologies on the rise that could make devices more independent from power outlets. When it comes to energy harvesting for wearables, science and industry are currently focusing on the following technologies:

 

Solar cells not only make sense on rooftops or in big solar parks, soon much smaller versions could provide enough energy to power wearable devices. Solar watches that function without batteries have been around for years, and Energy Bionics recently invented a watch that can produce enough energy to additionally be able to charge your mobile phone or other devices. One of the problems solar cells on wearables have is that they only work if directly exposed to the light and stop producing energy as soon as they are covered up, for example, under a sleeve. This, however, makes solar energy harvesting an interesting option for smart cloths, where flexible cells could be woven straight into the textile. Traditional solar cells are designed to absorb sunlight, which is much brighter than the indoor light sources in modern working environments. To address this issue, new materials for solar cells are being developed that are capable of producing energy indoors and with a much higher efficiency.

 

Thermoelectric harvesting transforms heat into electric energy using a physical principle called the Seebeck effect. Peltier elements, a certain pair of semiconductors, produce an electrical current whenever a temperature gradient occurs, so whenever one side is warmer than the other. For wearables, the human body, which is constantly emitting heat, might be used as the hot side of the equation while the surroundings can pose the cooler side that is needed for thermoelectric harvesting. The amount of energy that can be produced depends on the delta between the high and low temperatures. Peltier elements could deliver a comparably high amount of energy, making them interesting for devices worn in direct contact with the skin and with a high energy demand. One of the major benefits of thermoelectric harvesting is that the energy is always available, both indoors and outdoors, day and night.

 

Piezoelectric harvesting converts mechanical energy from vibrations or shocks into electrical energy. In piezoelectric elements, the piezo effect generates a small electrical current whenever the element is manipulated by mechanical forces. For energy harvesting in wearables, the piezoelectric elements are often designed to produce energy with the vibrations that occur when walking, breathing or moving your hands. Piezoelectric harvesting generates comparably small amounts of energy, which limits the technology to applications with low power demands and to body areas continuously in motion. Scientists are also working on polymeric piezoelectric fibres which are flexible, strong, breathable and could be integrated into textiles, allowing for a whole new range of health monitoring and other applications.

 

Optimizing Energy Storage and Consumption in Wearables

 

When it comes to new types of wearables that can run with less energy or completely without charging, energy harvesting is only one side of the story. Storing energy is another area with plenty of room for improvement - here, supercapacitors and graphene show lots of potential. Today's wonder material graphene might significantly improve the efficiency of batteries and capacitors, thus improving wearables' overall performance. And structural capacitors might manage turning the casing and other wearable components into an energy store, thus reducing the amount of space needed for a separate battery.

 

Another way to either improve battery life or become fully independent from charging batteries is to reduce the amount of energy it takes to operate sensors, chips and communication systems. While the smartphone's success has lead to powerful and energy-efficient processors for mobile devices, activity trackers, smart watches and other smart devices, wearables' processors generally have a much lower demand for computational power and energy supply. Big chipset vendors such as Intel are working to address the issue by integrating processors, memory and communication into a single chip, which would reduce the typical energy loss found in most companies' regular setup.

 

Choosing the most efficient network technology could provide additional opportunities to reduce energy consumption. Therefore, wearables might soon be equipped with several different wireless technologies, such as LTE, WiFi and Bluetooth simultaneously, in order to be able to pick the most energy-efficient and readily available solution depending on the given situation. Glimpsing into the future with a whole array of sensors and devices worn in different body areas, increasing the efficiency of communication within the so called "body area network", offers huge opportunities for energy saving. Companies such as EnOcean have developed optimized protocols that allow for much shorter data telegrams compared to the IPv6 formats, which leads to a significantly lower power consumption for the same amount of information.

 

All these different improvements can be used to provide truly self-powering wearables or to increase the performance of wearables with high energy demands due to complex systems for sensing, processing or displaying information. Combined with wireless energy supplies for inductive charging, consumers might soon experience significant improvements in the maintenance of their wearables, which in return would push the boundaries of acceptance for wearable technologies into broader markets..  The Wearable technologies conferences are in Milan  and San Francisco this year. 

 

RELATED ARTICLE:

 

Wearables Technologies Market Trends through 2018

For complete article click here

KEY FINDINGS:

- By 2020, well over 150 million wearable devices will ship worldwide, led by the sports and fitness sectors. Advertisers will likely use exercise data and eating to serve up relevant ads and offers;

- Increased attention toward personal health combined with a movement on the part of providers to contain costs, will trigger products and services that promote preventive measures;

- Wearable technologies will also emerge in the huge disability market (such as aids for the deaf, blind, paralyzed and elderly).

- In manufacturing and enterprise markets, wearable computers for hands-free operation will continue their popularity in field service and assembly lines and warehouses.

- Forecasts for global smartwatch shipments will grow from 1 million units in 2013 to 7 million in 2014. Credit Suisse expects the industry to grow from between $3 billion and $5 billion today to $50 billion within five years.

This report is a must-have for professionals interested in creating profit from the wearable computing market. 

 

 

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By Kevin Bullis,  MIT Technology Review, 02-01-15

 

 

 

Researchers solve key challenges with energy-dense lithium-air batteries. 

 

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3) Electric Cures For Arthritis, Diabetes Even Cancer

  

4) Emerging Energy Projections by Former DOE Director

By David Talbot, February 5, 2015, MIT 

http://www.technologyreview.com/qa/534856/qa-steven-chu/?utm_campaign=newsletters&utm_source=newsletter-daily-all&utm_medium=email&utm_content=20150209

 

The former Energy Secretary, who has begun chasing emerging technologies again, looks back on his successes and failures in government. 

 

As a leading and active scientist, Steven Chu broke the mold when he became energy secretary of the United States in 2009. In his four years of service, he made the Department of Energy more innovative, launching the Advanced Research Projects Agency for Energy to support projects not yet ready for private investment. He also created Innovation Hubs to bring people from different disciplines together on energy problems and rejuvenated funding for solar research. Chu, who shared the 1997 Nobel Prize in physics and directed the Lawrence Berkeley National Laboratory before his government appointment, is now restarting his research group at Stanford. In a conversation with David Talbot, chief correspondent of MIT Technology Review, he reflected on his time with the federal government and talked about the research and technology questions absorbing him today.

 

What left you the most frustrated or disappointed at the Department of Energy?

The press was sometimes frustrating to deal with. Often, reporters or their editors wanted to "make news" by generating controversy.

 

Inside the department, there was inertia to keep old programs unchanged, and friction against new approaches. For example, in research in biofuels, I wanted to cast a wide net for new ideas, but I was getting resistance against doing new research that didn't fit existing definitions of fuels listed by the Department of Agriculture. I wanted new ideas to be funded on the merits, and worry about categorization later.

 

What do you see as your biggest success and your biggest mistake?

My biggest success is that I was able to help recruit very capable scientists and engineers. Also, as a practicing scientist-during late nights or weekends-I was in a better position to ask the right questions. Perhaps my biggest mistake was to defer too much to "experts" on nonscientific matters at the beginning of my tenure. This was especially true if the advice was coming from handwringers who were more worried about negative reactions than doing the right thing.

Dr. Steven Chu

 

What should President Obama try to get done on energy in his final two years?

President Obama, through the EPA, is doing the right thing by pushing on mercury, particulate matter, and carbon dioxide standards for all power plants above a certain size. I would like to have him begin a dialogue on policies for countries that have a meaningful price on carbon or are working to be less carbon-intensive in each particular industry.

 

For example, the carbon emission from the production of a particular grade of steel varies greatly. We need to think of how to prevent manufacturing and extraction industries from constantly migrating to the lowest-cost, most polluting producer. China is working hard to reduce the carbon intensity of its industries and is likely to put a price on carbon. I believe China and the U.S. can be leaders in starting this dialogue.

 

What projects excite you now?

After I left DOE, many companies asked me to join their boards of directors. I chose very few, including Amprius [a Stanford startup working on lithium-ion batteries]. Professor Yi Cui [a 2004 member of MIT Technology Review's Innovators Under 35] and I brainstormed about new approaches to lithium-metal-anode batteries. We've published a couple of papers on new approaches. It's long been known that a lithium-metal-sulfur-cathode battery can potentially have five times higher energy density. We also seek a durable battery that can charge 10 times faster. Of course, as in all research, we may or may not succeed, but I think we have a shot.

 

You're also on the board of a Canadian startup called Inventys. Why?

I'm trying to help with some of the more technical aspects of capturing carbon from a natural-gas power plant-but also a coal, steel, or cement plant. Currently conventional methods that use amines [chemicals that absorb and then release carbon dioxide at different temperatures] are too expensive. We're hoping to reduce capture costs to $15 a ton for carbon dioxide; current technologies, when scaled, would cost around $60. Getting to $15 would make carbon capture feasible in the U.S. and China.

 

What's the fundamental physics breakthrough you'd most like to see?

Breakthroughs, by definition, are unanticipated surprises that lead to great things.

 

 

 

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5)National Clean Energy Summit

  

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